Safety Belt 

Countermeasures Study 

Final Report 

December 2007

FOREWORD 

This report addresses two different but interrelated topics of research. The first topic is the 

review of existing and potential future technologies that could improve safety belt use rates by 

drivers of large trucks (gross vehicle weight rating [GVWR] of 10,001 pounds or more). The 

second presents an analysis of real-world crash data, identifying common characteristics of fatal 

and serious injury crashes involving Commercial Motor Vehicle (CMV) drivers. The analysis 

explores the potential impact of increased safety belt use on driver fatalities and serious injuries. 

The Fatality Analysis Reporting System (FARS) and the Large Truck Crash Causation Study 

(LTCCS) databases were used to perform the review. 

This report discusses currently available technologies identified during a systematic review of 

technical publications and other available information sources. A summary of industry 

stakeholder and CMV driver perspectives regarding each technology is provided. Stakeholders 

included members of the CMV Safety Belt Partnership such as vehicle and restraint 

manufacturers, insurance, government, and CMV drivers. The results of an estimated benefitcost analysis are provided to compare potential injury and fatality reductions with estimated 

device costs. 

The data analysis tasks identified key environmental, vehicle, and driver factors describing the 

belted and unbelted driver populations. Causes of rollover crashes are identified and the impact 

of safety belt use on injury and fatality outcomes are explored. 

NOTICE 

This document is disseminated under the sponsorship of the Department of Transportation in the 

interest of information exchange. The United States Government assumes no liability for its 

contents or the use thereof. 

The contents do not necessarily reflect the official policy of the Department of Transportation. 

This report does not constitute a standard, specification, or regulation. 

The United States Government does not endorse products or manufacturers. Trade or 

manufacturers’ names appear herein only because they are considered essential to the objective 

of this document. 
Technical Report Documentation Page 

1. Report No. 

FMCSA-RRR-07_029 

2. Government Accession No. 3. Recipient’s Catalog No. 

5. Report Date 

December 2007 

4. Title and Subtitle 

Safety Belt Technology Countermeasures Study 

6. Performing Organization Code 

7. Author(s) 

George Bahouth, Elizabeth Langston, A. James McKnight, Eduard Zaloshjna, Jerry 

Robin, and Janet Kumer 

8. Performing Organization Report No. 

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) 

Pacific Institute for Research and Evaluation 

11720 Beltsville Drive, Suite 900 

Calverton, Maryland 20705 

Phone: 301-755-2700 Fax: (301) 755-2799 

11. Contract or Grant No. 

GS-10F-0128R 

13. Type of Report and Period Covered 

Final Report, December 2007 

12. Sponsoring Agency Name and Address 

Department of Transportation 

Federal Motor Carrier Safety Administration 

Office of Research and Analysis 

1200 New Jersey Ave. SE, Room 600 West 

Washington, DC 20590

14. Sponsoring Agency Code 

FMCSA 

15. Supplementary Notes

Mr. Jerry Robin was the Contracting Officer’s Technical Representative (COTR) for this project. 

16. Abstract: 

Safety belts are the single most effective injury prevention component of highway vehicles today. In 2006, observational 

studies reported that safety belt use by drivers of Class 7 and 8 trucks was 59 percent compared with an 81 percent belt 

use rate for passenger vehicle drivers. This study explored addresses two topics of research. The first topic explored 

technologies designed to increase safety belt use by commercial motor vehicle (CMV) drivers. Four promising 

technologies likely to increase safety belt use were identified: (1) Enhanced Audible Reminder Systems, (2) Brightly 

Colored Safety Belts, (3) Safety Belt Tension Adjustors, and (4) Seat-Integrated Safety Restraint Systems. A cost-benefit 

analysis was performed, indicating that brightly colored safety belts and enhanced audible reminders are both costbeneficial solutions, suggesting that the likely injury cost savings due to increased safety belt use will exceed the cost 

required to equip one vehicle with the device. At the present time, no Federal regulations exist that require safety belt 

reminder systems of any kind (audible or visual) for CMVs. Conversely, for passenger vehicles, the Code of Federal 

Regulations Part 571, Federal Motor Vehicle Safety Standard Number 208, requires that audible and visual reminder 

systems are installed at the driver’s seating position. This requirement has been in place since 1974. 

The second topic of research employed the FARS, NASS, GES, and LTCCS databases to perform a detailed 

analysis of fatal and serious injury crashes and to identify characteristics of the unbelted driver population. The 

analysis also explored the causes of rollover crashes and the likely impact of belt use on the frequency of driver injuries 

and fatalities. The data analysis identified that for both belted and unbelted drivers, the majority of CMV driver 

fatalities occurred during rollover crashes, followed by impacts with other vehicles. A review of unbelted driver 

fatalities and serious injuries indicated that 39 percent of unbelted driver fatalities (138 drivers per year) could be 

prevented with safety belt use and 47 to 81 percent of moderately to seriously injured drivers (1,600 to 2,500 drivers per 

year) could have sustained injuries less severe if they were properly restrained 

17. Key Words 

Crash Causation, Driver Injury, Large Truck, Rollover, 

Safety Belt 

18. Distribution Statement 

19. Security Classif. (of this report) 

Unclassified 

20. Security Classif. (of this page) 

Unclassified 

21. No. of Pages 

111 

22. Price 

N/A 

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized. 
SI* (MODERN METRIC) CONVERSION FACTORS 

APPROXIMATE CONVERSIONS TO SI UNITS APPROXIMATE CONVERSIONS FROM 

Symbol When You Know Multiply By To Find Symbol Symbol When You Know Multiply By T

LENGTH LENGTH 

in inches 25.4 millimeters mm mm millimeters 0.039 inft feet 0.305 meters m m meters 3.28 feyd yards 0.914 meters m m meters 1.09 ymi miles 1.61 kilometers km km kilometers 0.621 m

AREA AREA 

in2 square inches 645.2 square millimeters mm2 mm2 square millimeters 0.0016 sft2 square feet 0.093 square meters m2 m2 square meters 10.764 syd2 square yards 0.836 square meters m2 m2 square meters 1.195 sac acres 0.405 hectares ha ha hectares 2.47 ami2 square miles 2.59 square kilometers km2 km2 square kilometers 0.386 s

VOLUME VOLUME 

fl oz fluid ounces 29.57 milliliters ml ml milliliters 0.034 flgal gallons 3.785 liters l l liters 0.264 gft3 cubic feet 0.028 cubic meters m3 m3 cubic meters 35.71 cyd3 cubic yards 0.765 cubic meters m3 m3 cubic meters 1.307 c

MASS MASS 

oz ounces 28.35 grams g g grams 0.035 olb pounds 0.454 kilograms kg kg kilograms 2.202 pT short tons (2,000 pounds) 0.907 megagrams Mg Mg megagrams 1.103 sh

p

TEMPERATURE (exact) TEMPERATURE (exact) 

°F Fahrenheit 5(F-32)/9 Celsius °C °C Celsius 1.8 C + 32 F

temperature or (F-32)/1.8 temperature temperature te

ILLUMINATION ILLUMINATION 

fc foot-candles 10.76 lux lx lx lux 0.0929 fofl foot-lamberts 3.426 candela/m2 cd/m2 cd/m2 candela/m2 0.2919 fo

FORCE and PRESSURE or STRESS FORCE and PRESSURE or ST

lbf pound-force 4.45 newtons N N newtons 0.225 ppsi pound-force per square inch 6.89 kilopascals kPa kPa kilopascals 0.145 p

p

* SI is the symbol for the International System of Units. Appropriate rounding should be done to comply with Section 4 of A
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TABLE OF CONTENTS 

ACRONYMS............................................................................................................................... IV

EXECUTIVE SUMMARY ..........................................................................................................V

1. INTRODUCTION......................................................................................................................1

2. LITERATURE REVIEW .........................................................................................................3

2.1. COMFORT ......................................................................................................................3 

3. TECHNOLOGIES EXPLORED............................................................................................14

3.1. SAFETY BELT SYSTEMS CURRENTLY AVAILABLE IN LARGE TRUCKS .....14 

4. STAKEHOLDER AND DRIVER PERSPECTIVES...........................................................25

4.1. INDUSTRY PERSPECTIVES......................................................................................26 

4.2. DRIVER PERSPECTIVES ...........................................................................................33 

5. BENEFIT-COST ANALYSIS ................................................................................................40

5.1. INJURY COSTS............................................................................................................40 

5.3 BENEFIT-COST RATIOS.............................................................................................47 

CHAPTER 6. TECHNOLOGY SUMMARY............................................................................50

6.1. ENHANCED AUDIBLE REMINDERS.......................................................................50 

6.2. BRIGHTLY COLORED SAFETY BELTS..................................................................52 

6.3. SAFETY BELT TENSION ADJUSTORS ...................................................................53 

6.4. SEAT-INTEGRATED SAFETY RESTRAINTS .........................................................54 

CHAPTER 7. CRASH DATA ANALYSIS ...............................................................................56

7.1. CHARACTERISTICS OF FATALLY INJURED UNBELTED CMV DRIVERS......56 

7.2. CHARACTERISTICS OF FATALLY INJURED AND BELTED CMV DRIVERS..70 

7.3. CHARACTERISTICS OF FATAL ROLLOVER CRASHES......................................78 

7.4. ROLLOVER CRASH CAUSATION............................................................................81 

8. CONCLUSIONS ......................................................................................................................92

8.1. SUMMARY...................................................................................................................95 

REFERENCES.............................................................................................................................99

i 
LIST OF TABLES 

Table 1. Observed Safety Belt Use With and Without the Ford BeltMinder System .................... 8 

Table 2. Observed Belt Use by Trailer Type in Class 7 and 8 Trucks ......................................... 11 

Table 3. Estimated Sales of Large Trucks Equipped with Active and Passive Safety Belt 

Reminders. .............................................................................................................................. 15 

Table 4. Annual Injury Cost Savings If Drivers of All Large Truck Crashes Were Belted ......... 43 

Table 5. Annual Economic Injury Cost Savings If All Class 7 and 8 Truck Drivers in Crashes 

Were Belted ............................................................................................................................ 44 

Table 6. Estimated Safety Belt Device Costs ............................................................................... 46 

Table 7. Maximum Device Cost versus Anticipated Effectiveness.............................................. 47 

Table 8. Generalized Benefit-Cost Ratios for Safety Belt Technologies for Drivers of 

All Large Trucks—Anticipated Increase in Safety Belt Usage (from 59% baseline) ............ 48 

Table 9. Generalized Benefit-Cost Ratios for Safety Belt Technologies for Class 7 and 8 

Drivers—Anticipated Increase in Safety Belt Usage (from 59% baseline)............................ 49 

Table 10. Fatalities for Belted and Unbelted Drivers of All Large Trucks .................................. 57 

Table 11. Fatalities for Belted and Unbelted Drivers of Class 7 and 8 Trucks ............................ 57 

Table 12. Distribution of Harmful Event Categories for CMV Driver Fatalities for All Large 

Trucks ..................................................................................................................................... 59 

Table 13. Distribution of Harmful Event Categories for CMV Driver Fatalities in 

Class 7 and 8 Trucks............................................................................................................... 60 

Table 14. Distribution of Harmful Event Categories for Drivers of All Large Trucks, 

Unbelted and Belted................................................................................................................ 61 

Table 15. Distribution of Harmful Event Categories for Drivers of Class 7 and 8 Trucks, 

Unbelted and Belted................................................................................................................ 62 

Table 16. Vehicle Damage Severity Coded in FARS for Belted and Unbelted for Drivers of All 

Large Trucks ........................................................................................................................... 62 

Table 17. Vehicle Damage Severity Coded in FARS for Belted and Unbelted Drivers of 

Class 7 and 8 Trucks............................................................................................................... 63 

Table 18. Fatal Crashes by Roadway Type for Drivers of All Large Trucks............................... 63 

Table 19. Fatal Crashes by Roadway Type for Drivers of Class 7 and 8 Trucks......................... 64 

Table 20. Fatal Crashes by Weather Conditions for Drivers of All Large Trucks ....................... 64 

Table 21. Fatal Crashes by Weather Conditions for Drivers of Class 7 and 8 Trucks ................. 65 

Table 22. Fatalities by Time of Day and Belt Use for All Large Trucks ..................................... 66 

Table 23. Distribution of Driver Fatalities in 2005—Vehicle Configuration Versus Cargo........ 67 

Table 24. Unweighted Driver Counts by MAIS Injury Level for Drivers of All Large Trucks... 71 

Table 25. Weighted Driver Counts by MAIS Injury Level for Drivers of All Large Trucks....... 72 

Table 26. Potentially Preventable Deaths and Reduced Injuries if Safety Belts Had Been 

Used—Unweighted Counts .................................................................................................... 77 

Table 27. Potentially Preventable Deaths and Reduced Injuries if Safety Belts Had Been 

Used—Weighted Counts ........................................................................................................ 77 

ii 
Table 28. Survivability by Ejection Occurrence for Unbelted Drivers Who Sustained 

MAIS 2+ Injuries—Effect of Safety Belt Use on Injury Mitigation ...................................... 78 

Table 29. Fatal Occupant Ejection Counts for Planar and Rollover Crashes of Class 7 and 8 

Trucks ..................................................................................................................................... 79 

Table 30. Driver Fatality Counts During Rollover Crashes by Roadway Type for Class 7 and 8 

Trucks ..................................................................................................................................... 79 

Table 31. Fatal Rollover Crashes by Roadway Alignment for Class 7 and 8 Trucks .................. 80 

Table 32. Fatal Rollover Crashes by Vehicle Configuration and Cargo Type for Class 7 and 8 

Trucks ..................................................................................................................................... 80 

Table 33. CMV Rollover Crashes by Body Type......................................................................... 81 

Table 34. Causal Factors During CMV Rollover Crashes............................................................ 83 

Table 35. Causal Factors Related to Speed Occurring During Rollover Crashes Involving 

Drivers of All Large Trucks Sorted by Frequency of Occurrence.......................................... 84 

Table 36. Causal Factors Related to Fatigue, Attention, and Distraction Occurring During 

Rollover Crashes Involving Drivers of All Large Trucks ...................................................... 86 

Table 37. Causal Factors Related to Control Occurring During Rollover Crashes Involving 

Drivers of All Large Trucks.................................................................................................... 87 

Table 38. Causal Factors Related to Visual Search During Rollover Crashes Involving 

Drivers of All Large Trucks.................................................................................................... 88 

Table 39. Causal Factors Related to Preoperation During Rollover Crashes Involving 

Drivers of All Large Trucks.................................................................................................... 89 

Table 40. Other Causal Factors Occurring During Rollover Crashes Involving Drivers of 

All Large Trucks..................................................................................................................... 90 

Table 41. Causal Factors Related to the Vehicle Occurring During Rollover Crashes Involving 

Drivers of All Large Trucks.................................................................................................... 90 

LIST OF FIGURES 

Figure 1. Komfort Latch System .................................................................................................. 20 

Figure 2. Sliding Comfort Latch System ...................................................................................... 21 

Figure 3. Adjustable D-Ring......................................................................................................... 21 

Figure 4. Seat-Integrated Three-Point Restraint ........................................................................... 22 

Figure 5. Example of a Brightly Colored Safety Belt for CMV Operators .................................. 23 

Figure 6. Fatalities by Time of Day and Belt Use for Drivers of All Large Trucks..................... 66 

Figure 7. Distribution of Class 7 and 8 Truck Driver Fatalities ................................................... 68 

Figure 8. Driver Body Mass Index (BMI) for Fatally Injured Drivers of All Large Trucks........ 69 

Figure 9. Interior Photo of Case Vehicle Showing Extensive Steering Deformation .................. 74 

Figure 10. Interior Photo of the Principal Other Vehicle (Crash Partner) Showing no Steering 

Deformation ............................................................................................................................ 75 

Figure 11. Exterior View of Case Vehicle Where Unbelted Driver Was Severely Injured 

(MAIS 4) and Belted Passenger Sustained Minor Injuries (MAIS 1) .................................... 75 

Figure 12. Exterior View of Principal Other Vehicle Where Both Belted Occupants Sustained 

Minor Injuries (MAIS 1)......................................................................................................... 76 

iii 
ACRONYMS 

ABS Antilock Brake (or Braking) System 

ADR Australian Design Rule 

AIS Abbreviated Injury Score 

ATRI American Transportation Research Institute 

BCA Benefit-Cost Analysis 

BCR Benefit-Cost Ratio 

BMI Body Mass Index 

CDS Crashworthiness Data System 

CHAMPUS Civilian Health and Medical Program of the Uniformed Services 

CMV Commercial Motor Vehicle 

DCI Detailed Claims Information 

DOT Department of Transportation 

EOBDR Electronic Onboard Data Recorder 

FARS Fatality Analysis Reporting System 

FHWA Federal Highway Administration 

FMCSA Federal Motor Carrier Safety Administration 

FMVSS Federal Motor Vehicle Safety Standards 

GES General Estimates System 

GVWR Gross Vehicle Weight Rating 

HARM Hazard Assessment Rating Methodology—a metric used to characterize 

the number and severity of injuries sustained and overall cost to society 

LTCCS Large Truck Crash Causation Study 

MAIS Maximum Abbreviated Injury Score 

MVOSS Motor Vehicle Occupant Safety Survey 

NASS National Accident Sampling System 

NCCI National Council on Compensation Insurance 

NHTSA National Highway Traffic Safety Administration 

NMES National Medical Expenditure Survey 

NOPUS National Occupant Protection Use Survey 

NTC National Transport Commission 

NTSD National Truck Driving Championships 

OEM Original Equipment Manufacturer 

SOII Survey of Occupational Injury and Illness 

TMA Truck Manufacturers Association 

iv 
EXECUTIVE SUMMARY 

The first goal of this project was to identify promising technologies to increase safety belt usage 

by commercial motor vehicle (CMV) drivers. Each technology could be classified in one of 

three categories: (1) Comfort Strategies, (2) Reminder Strategies, or (3) Enforcement Strategies. 

The second phase of the study involved the analysis of real-world crash data from the Fatality 

Analysis Reporting System (FARS), National Accident Sampling System (NASS), and General 

Estimates System (GES) databases and the Large Truck Crash Causation Study (LTCCS) 

database to identify characteristics of fatal and serious injury crashes involving CMV drivers. 

The analysis considered common characteristics of belted and non-belted drivers of all large 

trucks, defined as any vehicle with a Gross Vehicle Weight Rating (GVWR) over 10,000 

pounds. 

This study identified four promising technologies likely to increase safety belt use. These are: 

(1) Enhanced Audible Reminder Systems, (2) Brightly Colored Safety Belts, (3) Safety Belt 

Tension Adjustors, and (4) Seat-Integrated Safety Restraint Systems. These technologies 

provide audible and visual reminders for drivers to buckle up or they improve the comfort of 

existing safety belt systems to address complaints made by some drivers. 

During the study, technologies to increase safety belt usage were identified during a systematic 

review of technical publications and other available information sources. This report contains a 

brief description of each technology considered. Discussions with industry stakeholders, 

including vehicle and restraint manufacturers, trade organization representatives, insurance and 

safety researchers, and CMV drivers, were conducted to better understand their perspectives on 

the safety belt use problem and the various technologies considered. A benefit-cost analysis was 

performed to estimate the potential injury and fatality cost savings likely if a fleet owner or 

vehicle owners chose to equip their vehicles with any of the devices in question. 

The study concluded that increased safety belt usage would reduce the number of seriously and 

fatally injured drivers. The economic burden associated with these casualties due to non-use of 

safety belts for drivers of large trucks is estimated to be $675 million annually. The cost of 

unbelted driver injury and fatality is $490 million for Class 7 and 8 trucks. In general, only 

approximate estimates of the effectiveness of each device in increasing safety belt use can be 

made because many of these systems have not been formally evaluated. However, study results 

indicate that if a device increases safety belt use by at least 15 percent, e.g., increases the rate 

from 59 percent to 74 percent, and the device cost is $273 or less per vehicle, the device is 

considered to be cost beneficial. For Class 7 and 8 trucks alone, if the device costs less than 

$725 and is 15 percent effective in increasing safety belt wearing rates, the system is cost 

beneficial. Most of the technologies considered during this study are significantly less expensive 

than $725 and would therefore be cost-beneficial solutions to increase safety belt use. If a device 

increases safety belt use by as little as 5 percent, then a device that costs as much as $91 for all 

large trucks or $240 for Class 7 and 8 trucks would be cost beneficial. 

Based on estimates performed here, brightly colored safety belts and enhanced audible reminders 

are both assumed to be cost-beneficial solutions. Their anticipated benefit cost ratios (BCRs) are 

1.70 and 2.60, respectively, for all large trucks. If the benefit cost ratio is greater than 1 for a 

particular device, it can be considered to be a cost-beneficial solution where the predicted injury 

v 
cost savings due to increased safety belt usage exceeds the cost required to equip one or more 

vehicles with the device. For drivers of Class 7 and 8 trucks alone, brightly colored safety belts 

and enhanced audible reminders have BCRs of 4.5 and 6.9. Alternatively, seat-integrated safety 

restraints could offer an enhanced comfort solution, yet device costs exceed the likely benefit of 

the proposed system based on calculations performed here. Safety belt tension adjustors 

(Komfort Latch), which are widely available today, are well suited to help CMV drivers 

configure safety belt systems for optimal comfort; however, significant driver education and 

training must occur in order to realize maximum effectiveness in increasing safety belt usage for 

these devices. 

The data analysis tasks (of the various DOT data crash systems, including GES, LTCCS, FARS) 

performed here identified key factors of the belted and unbelted CMV driver population. For 

both belted and unbelted drivers, the majority of CMV driver fatalities occurred during rollover 

crashes followed by impacts with other vehicles. A review of belted-driver fatalities indicated 

that virtually all rollovers involved significant damage to the occupant compartment. The most 

common crash types where a belted driver dies were rollovers with considerable roof crush or 

during events with side compartment intrusion. Further, impacts with fixed objects including 

roadside objects like bridge abutments and trees occur frequently during fatal crashes. Upon 

review of unbelted-driver fatalities and serious injuries, it was estimated that 39 percent of 

fatalities (138 drivers per year) could be prevented with safety belt use and 47–71 percent of 

moderately to seriously injured drivers (1,600–2,500 drivers per year) could have sustained 

injuries less severe if they were all properly restrained. 

Overall, increased safety belt use by drivers of large trucks would reduce the frequency and 

severity of driver injuries and fatalities. Several promising technological approaches likely to 

increase safety belt usage have been identified by this study. Some approaches must be adopted 

voluntarily by vehicle manufacturers or fleet owners when purchasing vehicles. Others could be 

addressed through improvements in existing regulations. The required introduction of basic 

audible or visual reminder systems would have some positive effects; however, the 

implementation of an enhanced system would likely bring a greater positive change in safety belt 

use. 

vi 
1. INTRODUCTION 

Safety belts are the single most effective injury prevention component of highway vehicles 

today. In the event of a crash, they are designed to prevent occupant ejection, limit excursion to 

prevent harmful contact with interior components, and minimize forces experienced by 

occupants as they are decelerated from driving speeds to rest. These primary functions of safety 

belts are true for any vehicle type. In all but one state, the use of safety belts is required for any 

person occupying a front-seat position in any motor vehicle, including large trucks. However, 

recent observational studies conducted in 2006 have shown that safety belt use by drivers of 

Class 7 and 8 trucks was only 59 percent overall. The most recent National Occupant Protection 

Use Survey (NOPUS), conducted in 2006, revealed that shoulder safety belt usage was 81 

percent for passenger vehicle drivers. 

This study investigates potential ways to increase safety belt usage for drivers of all large trucks 

with a Gross Vehicle Weight Rating (GVWR) of 10,001 pounds or more. For the remainder of 

this report, these vehicles are referred to as “All Large Trucks,” and in some cases they are 

referred to as Commercial Motor Vehicles (CMVs) as well. 

Many challenges are presented when attempting to lower safety belt use rates for drivers of large 

trucks. First, enforcement of safety belt use laws is more difficult for these drivers. Higher ride 

heights and enclosed occupant compartments obscure drivers from the view of police and U.S. 

Department of Transportation (DOT) inspection personnel. Multiple studies have shown that 

enactment and enforcement of safety belt use laws are the best way to improve safety-beltwearing rates for passenger vehicle drivers, yet drivers of large trucks do not appear to be as 

affected by these laws, due to the reduced threat of being identified as unbelted while driving and 

then ticketed. Also, given the size of the tractor trailers and their mass, these drivers feel safe not 

being buckled up. 

Drivers of CMVs have also indicated that safety belts are uncomfortable to wear while driving, 

and cite this as a primary factor in their decision not to buckle up. Although no scientific data 

support the claim that safety belts are uncomfortable in large trucks, varied seating geometry, 

suspended seating systems, and harsh rides, which are common in large trucks, could be 

responsible for the perceived discomfort. 

The goal of this study was to identify and evaluate promising technologies that could increase 

safety belt usage by CMV drivers. The study began with a review of all available scientific 

literature describing previously implemented technologies, currently available systems, and 

device concepts not already in use. Literature sources were selected that describe technologies 

specifically designed for large truck applications and those describing passenger vehicle systems 

that could be applied in large trucks. 

Discussions with trucking industry stakeholders were conducted to determine their perspectives 

on the CMV driver safety belt use problem and to seek their feedback regarding each potential 

device identified. Key findings of stakeholder discussions are presented in Chapter 4. 

Stakeholders included vehicle original equipment manufacturers (OEMs) and restraint 

manufacturers, trade organization representatives, fleet safety managers, government personnel 

1 
and trade association representatives, as well as insurance representatives; the vast majority of 

these stakeholders are members of FMCSA’s CMV Safety Belt Partnership. Chapter 4 also 

presents perspectives of CMV drivers regarding the various technologies considered. 

Discussions were held with full-time and part-time safety belt users and nonusers of safety belts. 

Based on industry stakeholder and driver feedback and through confirmation by drivers, the 

study focused on four promising technologies. These promising systems include: (1) Enhanced 

Audible Reminder Systems, (2) Brightly Colored Safety Belts, (3) Safety Belt Tension 

Adjustors, and (4) Seat-Integrated Safety Restraints. 

A benefit-cost analysis (BCA) was conducted to determine the monetary impact of increased 

safety belt use by drivers of all large trucks and by drivers of Class 7 and 8 trucks. This analysis 

is presented in Chapter 5. Results are presented in two generalized tables where benefit-cost 

ratios (BCRs) are calculated across a range of plausible device costs and a range of possible 

effectiveness values. This approach allows for the application of study results to estimate an 

approximate return on investment expected for any device that leads to an increase in safety belt 

use, as long as its cost and anticipated effectiveness are known. 

Within Chapter 6, a synthesis of information describing each of the four promising technologies 

is presented. This information includes any data discovered during the review of scientific 

literature and obtained from the stakeholders. A benefit-cost calculation tailored for each device 

is performed. In addition, a discussion of the implementation strategy and potential shortcomings 

of each system is provided. 

Chapter 7 presents the results of a general analysis of large-truck crash data. Within section 7.1, 

the 2005 Fatality Analysis Reporting System (FARS) data were reviewed to contrast vehicle, 

environmental, and personal characteristics for unbelted versus belted drivers of large trucks. 

The analysis was conducted to characterize the unbelted fatally injured population so that 

strategies can be generated to reduce the magnitude of this population. 

Chapter 7 also provides a detailed analysis of belted-driver fatal and serious-injury crashes, 

based on LTCCS data. This review was designed to better understand what factors led to 

fatalities for occupants who were properly restrained. The analysis also describes crash 

conditions not affected by safety belt usage. 

In addition, Chapter 7 presents a second evaluation using the LTCCS data to better understand 

primary causes of large-truck rollover crashes. Detailed crash case reviews were conducted to 

determine principal and secondary factors associated with rollovers. Factors were compiled 

based on crash-investigator-recorded data, as well as non-coded information collected during 

detailed clinical case reviews. Results of a subsequent factor analysis are presented, highlighting 

the most common contributors to the initiation of rollover crashes for all large trucks. 

2 
2. LITERATURE REVIEW 

A focused literature review was conducted to better understand technologies, including those in 

passenger cars, that are likely to increase safety belt usage by drivers of CMVs/all large trucks. 

In addition, the review sought to understand experiences of others who had systems implemented 

in the past. All available CMV safety belt technology studies and relevant passenger vehicle 

studies are presented. Literature search findings are grouped by their primary subject matter and 

placed in one of three topic categories, including comfort, reminder devices, and general 

information. 

2.1. COMFORT 

Four technical publications were found relating to safety belt comfort. These studies were based 

both on large truck applications and passenger vehicles. 

The first study, published by the National Transport Commission (NTC) of Australia (2004), 

investigated the hypothesis that safety belt comfort issues needed to be resolved in order to 

contribute to better wearing rates. The report, titled “Seat and Belt Configurations for Heavy 

Vehicles: Discussion Paper on Options for Improved Design,” considered 2004 new heavy 

vehicles sold in Australia in 2004 from the Truck Industry Council’s truck tracker data. 

Objectives of the study were to review the availability of seat and safety belt configurations in 

commercial vehicles sold in Australia and to test the theory that nonuse of CMV safety belts is 

due to discomfort. In particular, the study explored the current market presence, feasibility, and 

availability of seat-integrated safety restraints. 

Overall, the NTC of Australia study concluded that a compulsory standard requiring certain seat 

and safety belt configurations could lead to increased numbers of more comfortable safety belt 

systems. The authors suggested the following: (1) suspended seats with B-pillar mounted 

restraint systems provide reduced comfort to occupants due to the relative motion of the seated 

driver and belts that lead to excessive rubbing; (2) a fixed seat with a fixed safety belt system 

offers adequate comfort and is comparable to the same configuration in a passenger vehicle; and 

(3) a suspended seat with an integrated safety belt offers improved comfort. 

The NTC of Australia study identified that 46 percent of new heavy vehicles sold in Australia 

have fixed seats and B-pillar anchored safety belts, 31 percent have suspension seats and B-pillar 

anchored safety belts, and 23 percent have suspension seats and seat-integrated safety belts. The 

31 percent of vehicles sold with suspension seats and B-pillar anchored safety belts present an 

opportunity to improve the comfort of safety belts for new vehicles or retrofitted vehicles in the 

fleet. 

The NTC authors also identified that 12 percent of the fleets sold in Australia did not have cab 

designs with sufficient strength to withstand loads from a seat-integrated safety belt system. The 

authors suggested that European manufacturers are delivering 98 percent of new vehicles with 

safety belt configurations that are more comfortable than the B-pillar mounted system with a 

suspended seat. These included fixed seats with B-pillar mounted safety belts and suspended 

seats with seat-integrated safety restraints. The authors suggested that American manufacturers 

3 
are seeing increased demand for seat-integrated safety restraints, although 20 percent of new 

vehicle deliveries in 2004 were suspended seats with B-pillar mounted safety belt systems. 

The NTC study also compared reasons for resistance or nonuse of safety belts by truck drivers 

today and identified reasons given by passenger vehicle drivers for nonuse of safety belts when 

they were first introduced in those vehicles. Reasons cited by drivers were reported by Preece 

(2002) and include the following: 

• Restriction in the use of side mirrors 

• Discomfort during normal driving 

• Inconvenience when performing deliveries 

• Impeding the driver’s ability to move within or escape from the cabin in order to avoid 

injury during or after a collision 

• Difficulty in accessing and unlocking the safety belt 

• Getting entangled in the safety belt when exiting the cab 

Educational campaigns and high levels of enforcement were suggested to address these concerns. 

A study by Bergoffen, et al. (2005) summarized key information regarding factors that influence 

CMV drivers to use or to not use safety belts. The research was supported by DOT, Federal 

Motor Carriers Safety Administration (FMCSA). The study report included a literature review 

summarizing past and ongoing research on safety belt use by CMV drivers. A second source of 

information described in the report came from surveys of fleet managers and drivers. 

Bergoffen conducted truck stop interviews with 238 CMV drivers in Georgia and Wisconsin 

using a convenience sample. Commercial motor vehicle drivers were administered a five-minute 

interview where drivers were asked what percentage of the time they wore their safety belts 

while driving a truck. Of those interviewed, 61 percent reported wearing safety belts 95 percent 

or more of the time, and 21 percent of drivers reported wearing safety belts 5 percent or less of 

the time. Compared to the automobile driving population, where the group of habitual nonusers 

is 4 percent, this group of CMV drivers has more habitual nonusers, at 21 percent. There are also 

fewer full-time safety belt users among this group than in the general driving population—61 

percent compared to 76 percent, at the time the survey was conducted. The CMV drivers 

reported similar safety-belt-use behavior when driving their personal vehicles; that is, those that 

were not belted in trucks were also not belted in their cars. 

In Bergoffen’s study, the top reasons provided by the CMV drivers for not wearing a safety belt 

were: (1) comfort, (2) personal choice, and (3) dislike of wearing a safety belt. In the truck stop 

survey, drivers were asked about their biggest complaint regarding safety belts. Approximately 

62 percent responded to this question and of these, 28 percent (148) said they had no complaints 

about safety belts. The majority of the complaints referred to comfort issues, with only a few 

complaints about enforcement and personal choice. The major complaints about safety belt 

comfort were safety belt rubbing or vibrating against neck/shoulder, locking of safety belts, 

safety belt being uncomfortable, safety belt being too tight, and safety belt having a limited range 

of motion. The major suggestions that drivers gave to make the safety belt easy to use were that 

4 
it should: not be too tight, not interfere with driving, be easy to put on and take off, and be easy 

to position. 

In a survey of 120 fleet managers, Bergoffen stated that the managers provided the following 

reasons that drivers might not use safety belts: too much trouble and effort, just forgot, not a 

habit, belt does not fit well, uncomfortable for other reasons, restricts movement in vehicle, 

infringes on personal freedom, worries about being trapped in vehicle, don’t believe belts 

increase safety, just don’t like them, part-time users, and used only in bad weather. 

Two focus groups were held with CMV drivers during the Bergoffen study in Utah; one with 

seven drivers at the National Truck Driving Championships (NTDC) and one with four drivers at 

a private trucking terminal dubbed “Company A.” These focus groups were small and were held 

with groups of drivers who would be expect better safety related behaviors than the general 

CMV-driving public. Drivers from the Company A group indicated that because of the 

company’s strong belt policy, they all wore safety belts 100 percent of the time. The NTDC 

drivers did not wear belts all of the time. One stated that it was because it was not convenient 

when delivering door-to-door. Participants felt that of the valid reasons for not wearing a safety 

belt, discomfort was a top choice. 

During the evaluation, Bergoffen’s research team also conducted an ergonomics assessment of 

existing truck safety belts. The evaluation concluded that safety belts in large trucks are practical 

and functional. Researchers identified that safety belt systems are suitable for the majority of the 

population (20th percentile through the 80th percentile); however, safety belts do not serve well 

the population of large, heavy-set, obese drivers or the population of drivers of small stature. The 

study identified two features in new safety belts that make the placement of the shoulder strap 

more flexible. These are the adjustable height D-ring and the shoulder strap tension adjuster. The 

study also suggested that seat-integrated safety belts may enter the U.S. market; however, 

structural requirements, including crash test requirements, must first be addressed by 

manufacturers. 

In 2003, DOT established the CMV Safety Belt Partnership in response to the “Safety Belt 

Usage by Commercial Motor Vehicle (CMV) Drivers” study, which found that only 48 percent 

of CMV drivers were wearing their safety belts, compared to 80 percent of passenger vehicle 

drivers. The partnership is dedicated to increasing safety belt use among CMV drivers. In 2006, a 

similar CMV driver safety belt observation study was conducted by the National Highway 

Traffic Safety Administration (NHTSA) for FMCSA that showed usage had increased to 59 

percent, compared to 81 percent for passenger vehicle drivers. 

The CMV Safety Belt Partnership is comprised of the following organizations: 

• American Trucking Associations (ATA) 

• American Association of Motor Vehicle Administrators 

• American Society of Safety Engineers (ASSE) 

• Commercial Vehicle Safety Alliance (CVSA) 

• Federal Motor Carrier Safety Administration (FMCSA) 

• Great West Casualty Company 

5 
• International Association of Chiefs of Police (IACP) 

• National Association of Truck Stop Operators (NATSO) 

• National Association of Publicly Funded Truck Driving Schools 

• National Highway Traffic Safety Administration (NHTSA) 

• National Private Truck Council (NPTC) 

• National Safety Council 

• National Tank Truck Carriers 

• Network of Employers for Traffic Safety 

• Owner-Operator Independent Drivers Association (OOIDA) 

• Truck Manufacturers Association 

• Property Casualty Insurers Association of America 

• Truckload Carriers Association, Professional Truck Drivers Institute 

For more information about the partnership, visit www.fmcsa.dot.gov/safetybelt. 

Hayworth, et al. published “Truck Seat Belts” in 1996. The goals of the study were to determine 

the following: how many and what groups of heavy vehicle drivers did not wear safety belts; 

why truck drivers did not wear safety belts; what effect, if any, the changed Australian Design 

Rule (ADR) had had on wearing rates and whether further safety belt design improvements were 

required; what was necessary to achieve greater wearing rates; and the guidelines for the 

development and conduct of a communications strategy to improve safety belt wearing. 

According to Hayworth’s study, the ADR was changed (effective July 1992) so that safety belts 

could be anchored to vehicle seats and so that retractors (web-lockers) could be made less 

sensitive. The extent to which these changes (which made truck safety belts more comfortable) 

increased safety belt usage was explored. Findings indicated that wearing rates were higher in 

new trucks than in older trucks. This suggests that the changed ADR has improved wearing rates. 

However, when wearing rates were analyzed, drivers with seat-mounted safety belts were no 

more likely to wear the safety belt than those with vehicle-mounted systems. 

Balci, Vertiz, and Shen (2001) published a study that considered the comfort and usability of 

safety belts in passenger vehicles. During the study, 600 questionnaires were distributed and 192 

(32 percent) were returned. There was no information provided on who received the 

questionnaires. The low response rate and the skewed demographics (69 percent male, over 50 

percent between 41–55 years old) indicated that this population is not representative of the 

general passenger-vehicle-driving population. 

Balci, Vertiz, and Shen also conducted a survey to collect first-hand information regarding safety 

belt comfort and usability. The most significant problems with safety belts were: safety belt 

trapping in the door, awkward negotiating with clothes, safety belt twisting, safety belt locking 

up, and difficulty locating the buckle. The survey results indicated that drivers who are over 40 

years old had more complaints than younger drivers. When the driver’s age increased to 55 or 

more, safety belt pulling force and inappropriate and loose fit of the safety belt on the body 

became major issues. Female drivers had more complaints than male drivers. Drivers of short 

stature need both hands to pull and guide the safety belt. The participants who were in the 66th 

6 
percentile or higher in terms of weight had complaints about safety belt twisting. Coupe-type 

vehicles had the least comfortable safety belts compared to other vehicle types. The most 

comfortable safety belts were found in sedan and SUV-type vehicles. 

2.2. REMINDER DEVICES (PASSENGER VEHICLES) 

In a 2002 study, Fildes, et al. estimated the “Benefits of Seat Belt Reminder Systems” for the 

Australian population. The study presented results of an analysis of an aggressive safety belt 

reminder system for passenger vehicles to determine how cost-beneficial each of the systems 

would be for Australia. The three systems analyzed were: (1) a simple flashing light and warning 

tone, (2) a simple flashing light and warning tone where intensity increases with higher travel 

speeds, and (3) a system like the previous one where the hazard lights also flash (outside the 

vehicle) after a set period of noncompliance. The third system was considered the most invasive. 

Due to the uncertainty of the actual effectiveness and cost of such systems, the study presented a 

matrix of results for systems 10 percent to 40 percent effective, in 10 percent steps and for 

systems costing $25–$65 per device. 

Overall, Fildes’ study showed that the benefit-cost ratios (BCRs) varied significantly. Retrofitted 

safety belt reminder systems at the driver position would only be worthwhile if the device costs 

no more than $35 per vehicle and a minimum of 20 percent improvement were expected. 

Alternatively, the device would be worthwhile if a 30 percent improvement were expected and 

the devices cost less than $45 at both the driver and passenger positions. The methodology used 

to estimate BCRs contrasted the expected reduction in HARM (Hazard Assessment Rating 

Methodology, a metric used to characterize the number and severity of injuries sustained and 

overall cost to society) with the anticipated costs of such devices. 

Fildes’ study identified that safety belt reminders are most appropriate for those who forget to 

put their safety belts on rather than for those who actively refuse to use them. The study further 

found that safety belt reminders could be introduced as add-on devices and would not require 

major restructuring for passenger vehicles. 

In 2002, Williams, et al. investigated the “Effectiveness of Ford’s BeltMinder System in 

Increasing Seat Belt Use.” The study observed 2,334 drivers of model year 1998–2002 passenger 

cars, both those equipped and those not equipped with the Ford BeltMinder system. 

Williams’ study presented findings of observed usage rates for 1,521 non-BeltMinder-equipped 

Ford vehicles compared with safety belt usage rates for 813 BeltMinder-equipped vehicles. The 

study identified that the audible reminder chimed for 6 seconds, paused for 30 seconds, and 

repeated for up to 5 minutes if a front-seat occupant was present and unbuckled while the engine 

was started or if the vehicle was traveling more than 3 mph (differences existed based on the 

electronics of the vehicle). The study reported differences in safety belt use rate by vehicle type 

and driver gender. Table 1 summarizes the overall results of the evaluation and shows that a 3 

percent higher safety belt use rate was observed for male drivers of cars and minivans equipped 

with a BeltMinder system compared to those vehicles without the BeltMinder system. A 5 

percent higher safety belt use rate was observed for female drivers of cars and minivans with the 

BeltMinder system. For male pickup truck drivers, an 8 percent higher safety belt usage rate was 

7 
observed with the BeltMinder system, and for female pickup truck drivers a 4 percent increase in 

safety belt use was observed. For male SUV drivers, a 4 percent increase in safety belt use was 

observed with the BeltMinder and an 8 percent higher safety belt use rate was observed for 

females driving SUVs. 

A second study by Williams, et al. (2003) studied drivers’ opinions of Ford’s BeltMinder 

System. The goal of the study was to determine consumer reaction to the Ford BeltMinder 

System implemented in passenger vehicles and to compile self-reported safety belt use 

information as it related to the technology. Personal interviews of 405 drivers of vehicles with 

the reminder system were conducted at Ford dealerships. 

Table 1. Observed Safety Belt Use With and 

Without the Ford BeltMinder System 

Vehicle Type/ 

Driver Gender 

Driver 

Gender No Reminder Reminder Difference 

95% Confidence

Interval 

Car/minivan Male 74 77 3 –3.5 to 10.4 

Car/minivan Female 81 86 5 –1.9 to 11.0 

Pickup Male 58 66 8 –1.0 to 17.0 

Pickup Female 72 76 4 –16.9 to 24.9 

Utility Vehicle Male 68 73 4 –6.7 to 15.2 

Utility Vehicle Female 76 84 8 –3.1 to 18.8 

Overall, Williams’ 2003 publication stated that 73 percent of the respondents who experienced 

the reminder said that they buckled up as a result. Of those who did not buckle up, 58 percent 

ignored the noise, whereas 21 percent deactivated the system. Five percent of all respondents 

used methods described in the owner’s manual to permanently disable the system. In terms of the 

effect of the safety belt systems on behavior, 52 percent said that their safety belt use remained 

the same after the system was added, 46 percent said that they used safety belts more, 30 percent 

said that they used the safety belts much more, and 2 percent claimed lower safety belt use. 

When asked if they like the systems, 78 percent said yes, 18 percent said no, and 4 percent were 

undecided. 

Howell, et al. (2003) conducted a study for the Transportation Research Board and published 

“Special Report 278: Buckling Up: Technologies to Increase Seat Belt Use.” The study 

summarized an examination of the potential benefits of technologies designed to increase safety 

belt use in passenger vehicles as requested by Congress. The study also determined how 

passenger vehicle drivers view the acceptability of the technologies, and it considered whether 

legislative or regulatory actions were necessary to enable their installation on passenger vehicles. 

Howell’s study outlined reasons for part-time and habitual nonuse of safety belts based on 

NHTSA studies, including the Motor Vehicle Occupant Safety Survey (MVOSS) and the 

National Occupant Protection Use Survey (NOPUS). The study also provided a historical review 

8 
of experiences with safety belt use technologies, including light and buzzer reminders (1972), 

ignition interlocks (1973), and the 4- to 8-second warning light and buzzer system. 

Howell’s study found that audible reminder systems are effective and acceptable to passenger 

vehicle drivers. The technology is proven and reliable. Also, existing passenger vehicle 

technology (including safety belt buckle sensors and existing chimes) allows for simple 

implementation of an enhanced audible reminder. Final study recommendations included the 

following: 

• Congress should amend the statute regarding safety belt reminder systems by lifting the 

restrictions on systems with lights and chimes longer than eight seconds, which would 

provide NHTSA more flexibility and the authority to require effective safety belt 

reminder technologies. 

• Every new light-duty vehicle should have as standard equipment an enhanced safety belt 

reminder system for front-seat occupants with an audible warning and visual indicator 

that are not easily disconnected. Any auditory signal should be audible above other 

sounds in the vehicle. For the short term, manufacturers should be encouraged to provide 

these systems voluntarily. 

• NHTSA should encourage the industry to develop and deploy enhanced safety belt 

reminder systems in an expeditious time frame, and NHTSA should monitor the 

deployment. As differences in effectiveness and acceptability of safety belt reminder 

systems are identified, manufacturers should install systems that are determined by 

empirical evidence to result in the greatest degree of effectiveness while remaining 

acceptable to the general public. Should voluntary efforts not produce sufficient results, 

NHTSA should mandate the most effective acceptable systems as determined by the 

current data. 

• Rear-seat reminder systems should be developed at the earliest possible time, as rear-seat 

sensors become available. 

• NHTSA and the private sector should strongly encourage research and development of 

safety belt interlock systems for specific applications. 

• Safety belt use technologies should be viewed as complementary to other proven 

strategies for increasing safety belt use, most particularly the enactment of primary safety 

belt use laws that enable police to pull over and cite drivers who are not buckled up and 

well-publicized enforcement programs. 

• Congress should provide NHTSA with funding of $5 million annually to support a 

multiyear program of research on the effectiveness of different enhanced safety belt 

reminder systems. 

• In 2008, another independent review of safety belt use technologies should be conducted 

to evaluate progress and to consider possible revisions in strategies for achieving further 

gains in safety belt use, including elimination of the statutory restriction against 

NHTSA’s requiring vehicle interlock systems. 

In 1980, Geller, et al. published a study titled “Safety Belt Use in Cars with Starter-Interlock and 

Buzzer-Light Reminder Systems,” which described an observational study performed at a large 

southeastern university to understand the relationship between device intrusiveness and safety 

9 
belt wearing rates for passenger vehicles. A total of 1,827 drivers were observed during entry 

and exit at Virginia Tech University, and a subset of these drivers agreed to complete a 

questionnaire regarding their safety belt use behavior. 

Geller’s study identified overwhelming rates of disabling or defeating the interlock or continuous 

buzzer systems—62 percent of those interviewed disabled the systems. Of those who disabled 

the system, only 15.9 percent of the drivers buckled up. Of the remaining drivers with working 

interlocks or continuously sounding buzzers, all buckled up. The study concluded that unlimited 

buzzer systems would be optimal if methods to prevent defeating them were put in place. 

A study by Bentley, et al. (2003) found that the entertainment system interlock, as well as 

previously implemented transmission interlocks, crossed the line of “acceptable” devices to 

increase safety belt use. 

2.3. GENERAL SAFETY BELT INFORMATION: CMVS AND PASSENGER 

VEHICLES 

Preece, et al. (2002) published a study titled “Seat Belt Use by Heavy Truck Drivers—A Simple 

Way to Save Lives,” which was presented at the National Heavy Vehicle Safety Seminar held in 

Melbourne in October 2002. The objective of the study was to summarize three research studies 

commissioned by the Roads and Traffic Authority of New South Wales. The data sources 

include interviews with seven drivers (nonusers), case data from 205 crash events, and an 

observational study of 1,488 vehicles for safety belt use. 

The research topics summarized in Preece’s study included the attitudes and knowledge of truck 

drivers regarding safety belt use. These include restriction in the use of side mirrors, discomfort 

during normal driving with suspended seats and safety belts that lock, inconvenience when 

performing deliveries, impeding ability to move or escape to avoid injury after a collision, 

difficulty accessing and unlocking safety belt, and getting entangled in the safety belt when 

exiting the cabin. 

Preece, et al. noted that these reasons cited for nonuse of safety belts are similar to those raised 

by drivers of light vehicles before the introduction of compulsory safety belt use. The authors 

estimated that between 40 percent and 50 percent of fatalities can be prevented by safety belt 

use, based on their crash vehicles study data involving 205 crash events. They also cite 

effectiveness estimates from other sources; for example, Campbell and Sullivan (1991) estimated 

that between 27 percent and 77 percent of truck driver fatalities could be prevented with safety 

belt use. 

Finally, Preece’s study collected the observed safety belt use from roadside vantage points and 

vehicle inspection stations. Some 1,488 vehicle drivers were observed; 32 percent of these 

reported wearing a lap-sash safety belt, 30 percent had the lap-sash safety belt available but were 

not restrained, and 37 percent had a lap-sash safety belt available, but the level of use was 

unknown. Results were presented by seat position and truck type. 

Huey, et al. (2005) published a technical report for NHTSA that identified “Shoulder Belt Usage 

by Commercial Motor Vehicle Drivers.” This study reported the findings of an observational 

10 
study identifying shoulder safety belt usage rates by drivers of Class 7 and 8 vehicles. The goal 

was to collect a convenience sample of safety belt use data to identify changes that have occurred 

since the 2002 study was completed. The study identified issues related to the direct observation 

of safety belt use that would also hinder the enforcement of a mandatory safety belt use law. 

Data were collected over a six-week period at rest areas, truck stops, and exit ramps on or near 

limited access highways, as well as at intersections. Thirty observations at 10 sites were targeted 

per state (i.e., 300 total per state). The study report went into great detail regarding site sampling 

methods, observational procedures, and management strategies. 

Overall, the results of the Huey study were based on the observation of 4,740 trucks (compared 

to 3,909 in 2002). Truck stops/rest areas accounted for 46 percent of the observations, 38 percent 

were at signalized intersections on primary highways, 10 percent were on interstate exit/entrance 

ramps, and 6 percent were at signalized intersections on secondary highways. 

Table 2 shows Huey’s findings by vehicle type and class of truck for the 2002 and 2005 studies. 

Higher use rates were observed for major U.S. or regional companies. Of their drivers, 63 

percent were belted versus 41 percent for independent and local fleets. The authors suggested 

that educational programs and company policies may be used by many of the major carriers and 

may be the reason for higher use rates among their drivers. Similarly, higher use rates were 

confirmed for hazmat vehicle operators across all trailer types (75 percent use for hazmat vehicle 

operators and 54 percent overall for nonhazmat vehicle operators). 

Table 2. Observed Belt Use by Trailer Type in 

Class 7 and 8 Trucks 

Trailer Type Survey Year 

2005 (%) 

Survey Year 

2002 (%) 

Single Van 62 51 

Single Tanker 75 61 

Single Dump 23 26 

Doubles, All Types 59 56 

Bobtails 40 33 

All Class 8 54 47 

All Class 7 and 8 54 48 

 Source: Huey, et al. (2002, 2005). 

Observational safety belt use results reported by Huey, et al. (2006) showed that 59 percent of 

Class 7 and 8 drivers were wearing safety belts in 2006, up from 54 percent in 2005. Federal 

Motor Carrier Safety Regulations require CMV drivers to wear safety belts. For truckers driving 

for national or regional fleets, the use rate increased to 75 percent in 2006, up from 63 percent in 

2005. Independent drivers’ buckled-up rates increased in 2006 to 44 percent, compared with 41 

percent in 2005. As previously mentioned, the study was a convenience sample observing safety 

belt use by Class 7 and 8 truck drivers. Currently, there are no published data describing safety 

belt use rates for truck drivers of Class 4 to 6 vehicles. 

11 
Simon, et al. (2001) submitted a paper entitled “Potential Gain to be Achieved by Generalization 

of Seat Belts and Airbags in Trucks” to the 17th International Technical Conference on 

Enhanced Safety of Vehicles in the Netherlands. The study reviewed 403 accidents involving 

unbelted drivers of large trucks in France. Injury mechanisms were considered to calculate the 

expected benefits to large truck occupants if they were belted and, separately, if they were 

airbag-protected. The effect of the presence of the airbag in preventing fatalities was estimated to 

be minor relative to the effect of safety belt use. 

Simon calculated a surrogate for crash severity (EES and deltaV) based on crash investigation 

data and vehicle parameters. Individual case reviews were conducted to code the relative 

differences in injury severity that are likely with safety belt use. Case reviews were also 

conducted to estimate whether an occupant would have sustained his or her injuries if he or she 

had been belted. Injuries to each body region were classified in one of three categories: (1) 

intrusion of vehicle components or external objects, (2) projection of the occupant within the 

vehicle cab, and (3) ejection of the occupant from the vehicle cab. Crash types, crash severity 

(violence), and injury mechanism were considered. The study defined crash conditions that 

would and would not be affected by safety belt use, compiled data, and performed logistic 

regression to estimate injury and fatality risk changes with and without safety belts. 

Simon’s study summarized findings of other studies indicating that truck safety belt systems are 

50 percent to 60 percent effective in preventing injuries and 22 percent effective in preventing 

fatalities. In Europe, safety-belt-wearing rates were self-reported at 12 percent, whereas observed 

rates are at 1.5 percent in France and less than 5 percent in Germany. Sixty percent of crashes 

involving large trucks would not be affected by safety belts (i.e., side impacts and rear impacts). 

The crash types selected that would be affected by the use of safety belts were: (1) frontal 

crashes with another vehicle, (2) single-vehicle frontal crashes with a fixed object, and (3) 

rollover and tipover crashes. The most frequent injury cause was occupant excursion from a 

seated position, followed by contact with interior components, whereas intrusion and ejections 

led to the most serious injuries. The study identified that safety belt use (plus an airbag) would be 

effective in preventing 37 percent of the fatalities, 36 percent of serious injuries, and 22 percent 

of the slight injuries. 

A study by Siegmund, et al. identified a 26 percent to 37 percent increase in head, thoracic, and 

pelvic accelerations and a 20 percent to 54 percent increase in neck loads and moments of the 

addition of 10 centimeters of slack to a safety belt system. Most commercial vehicles do not 

come equipped with pretensioning retractors. Ideally, a safety belt system should closely couple 

an occupant to the decelerating vehicle structure as early as possible during a crash event. If 

additional slack exists in the system, the safety belt does not decelerate occupants for as long a 

period of time before the vehicle structure comes to rest. In this case, an occupant will 

experience a higher deceleration force over a shorter period of time before he or she is brought 

from precrash speeds to rest. 

NHTSA amended the passive restraint requirement calling for safety belt ignition interlocks in 

all 1974 model year vehicles. Although immediate increases in safety belt use rates were 

documented by NHTSA as a result of the ignition interlock requirement (30 percent reported by 

Robertson in 1975), considerable public opposition to the technology requirement led to 

amended legislation prohibiting ignition interlocks and continuous audible safety belt reminders 

12 
that same year. A less aggressive requirement was introduced in 1975 calling for a warning light 

to be displayed for 4 to 8 seconds and for a chime to sound until safety belts were buckled or 

eight seconds had passed. This is still a requirement for passenger vehicles. No such NHTSA 

requirement exists for CMVs. 

A 1995 study by Kratzke summarized the “Regulatory History of Automatic Crash Protection in 

FMVSS 208,” and outlined the history of the Federal Motor Vehicle Safety Standards (FMVSS) 

occupant protection requirements since safety belts were first introduced in passenger vehicles in 

1968. One portion of the paper describes the U.S. experience regarding mandatory ignition 

interlocks. In August 1973, all new cars were required to be equipped with automatic protection 

(like airbags) or with an ignition interlock for both front outboard seating positions. With few 

exceptions, all 1974 model year vehicles met the requirement. The study described public 

resistance to safety belt-starter interlock systems and suggested that methods to disable the 

systems were being widely disseminated and applied by users. The devices were introduced at a 

time when the benefits of safety belts were not widely known. In addition, new safety belt 

interlock systems did not work well technically and were prone to fault. On October 27, 1974, a 

law was passed that prohibited any Federal motor vehicle safety standard from requiring or 

permitting the use of any safety belt interlock system. 

13 
3. TECHNOLOGIES EXPLORED 

A review was conducted to identify previously implemented technologies, current systems in 

vehicles, and possible future systems that could increase safety belt use by CMV drivers. A basic 

description of all known safety belt technologies is presented in this section. Information sources 

include published data from the scientific literature, ideas proposed by industry stakeholders, and 

concepts under development by truck original equipment manufacturers (OEMs) or restraints 

manufacturers. In addition, an Internet search was conducted to identify any additional systems 

not discovered during a review of the above sources. 

3.1. SAFETY BELT SYSTEMS CURRENTLY AVAILABLE IN LARGE TRUCKS 

This section describes, in general, safety belts, reminder systems, and comfort devices currently 

available in CMVs sold in the United States. This information was compiled based on findings of 

the literature review presented in Chapter 2, through informal discussions with large truck 

OEMs, restraint suppliers and aftermarket device manufacturers, and based on data supplied by 

the Truck Manufacturers Association (TMA). 

3.1.1. Safety Belts 

In general, U.S. trucks are equipped with three-point safety belt systems; however, only twopoint safety belts are required by the U.S. Code of Federal Regulations, Part 571, FMVSS 

Number 208. The standard requires the installation of either two-point lap safety belts (Type I) or 

three-point lap shoulder restraints (Type II) at each outboard seating position in vehicles with a 

GVWR of 10,001 pounds or more. Due to frontal barrier crash requirements for these vehicles, 

most, if not all, manufacturers of large trucks choose to install three-point safety belts in order to 

meet the standard. In some specialized vehicles in which cab configuration does not lend itself to 

a B-pillar mounted D-ring, two-point safety belts may be installed for practical reasons. For 

passenger vehicles (weighing 10,000 pounds or less), Type II safety belts are required and Type I 

safety belts are not permitted as an option. 

3.1.2. Audible and Visual Reminders 

Currently, no Federal regulations require safety belt reminder systems of any kind (audible or 

visual), for vehicles with a GVWR of 10,001 pounds or more. 

A passive visual reminder system is one that illuminates a safety belt icon or a dash warning 

lamp for a finite period (usually 5–15 seconds) without actively sensing if the safety belt is 

buckled. Similarly, a passive audible reminder would chime or buzz for a set period of time 

without sensing if safety belts were fastened. After this period, the visual or audible system 

would shut off even if a driver had not fastened his/her safety belt. 

An active visual reminder would illuminate continuously or flash until safety belts are buckled. 

Typically, active systems use buckle sensor information to determine safety belt use status. An 

active audible reminder would chime continuously or intermittently until the buckle sensor or 

other data indicate that a belt has been fastened. 

14 
It should be noted that passenger vehicles weighing less than 10,000 pounds GVWR are required 

by NHTSA to have active technologies to remind drivers to buckle up when the vehicle is first 

started. No such requirement exists for vehicles weighing 10,001 pounds GVWR or more. The 

U.S. Code of Federal Regulations, Part 571, Federal Motor Vehicle Safety Standard Number 208 

states that for passenger vehicles, “The driver’s seating position shall be equipped with a 

warning system that, at the option of the manufacturer, either—activates a continuous or 

intermittent audible signal for a period of not less than four seconds and not more than eight 

seconds and that activates a continuous or flashing warning light visible to the driver displaying 

the identifying symbol for the safety belt telltale, or, at the option of the manufacturer if 

permitted by FMVSS 101, displaying the words ‘Fasten Safety Belts’ or ‘Fasten Belts,’ for not 

less than 60 seconds when the vehicle’s ignition switch is moved to the ‘on’ position or to the 

‘start’ position and the driver’s safety belt is not in use. Safety belt use is determined, at the 

option of the manufacturer, either by the safety belt latch mechanism not being fastened, or by 

the safety belt not being extended at least four inches from its stowed position” (Federal 

Register, 1974). 

Some manufacturers of large trucks have begun voluntarily equipping their vehicles with passive 

reminder systems (visual and audible), and some are voluntarily equipping vehicles with active 

systems (e.g., dash warning lights/telltales or audible reminders) that use a buckle sensor to 

determine safety belt use status. As suggested by the data in Table 3, smaller CMVs (Class 3–

Class 6) are more often equipped with passive and active reminder technologies compared with 

Class 7 and 8 vehicles. It is likely that instrumentation and safety systems for these vehicles are 

shared with other platforms weighing less than 10,000 pounds, where safety belt warning 

systems are required by FMVSS. 

As shown in Table 3, some 40 to 60 percent of Class 3 vehicles are equipped with active safety 

belt reminders. Virtually no Class 8 vehicles manufactured in 2006 are equipped with active 

systems. 

Table 3. Estimated Sales of Large Trucks Equipped with 

Active and Passive Safety Belt Reminders 

Vehicle Class 

Annual 

Production

in 20061 

Estimated Number 

of Model Year 2006 

Vehicles With 

Passive Safety Belt 

Reminders (%) 

Estimated Number 

of Model Year 2006 

Vehicles With Active 

Safety Belt 

Reminders (%) 

Class 3 (10,001–14,000 pounds GVWR)* 150,000 75–85 40–60 

Class 4 (14,001–16,000 pounds GVWR)* 50,000 60–80 30–50 

Class 5 (16,001–19,500 pounds GVWR)* 49,000 60–80 15–35 

Class 6 (19,501–26,000 pounds GVWR) 70,000 50–70 Fewer than 5 

Class 7 (26,001–33,000 pounds GVWR) 91,000 30–50 Fewer than 2 

Class 8 (33,001 or more GVWR) 284,000 30–50 Near 0 

1Based on truck sales data from Wards Automotive Group. Source: The Truck Manufacturers Association (TMA) supplied data 

and dealership reviews. TMA represents all of the major manufacturers of medium and heavy trucks over 19,500 pounds GVWR 

in the United States. Data for all weight classes are approximate based on information available. 

15 
Table 3 provides estimates of new vehicle sales with active and passive safety belt reminder 

systems. These data were supplied, in part, by TMA, where member companies reported sales 

percentages with and without the systems. At the request of the manufacturers, individual 

company percentages are not reported. TMA member companies include Ford, Freightliner, GM, 

International, Isuzu, PACCAR-Peterbilt/Kenworth, and Volvo/Mack. 

Addition information not supplied by TMA was gathered by the research team through newvehicle dealer interactions and through direct observation of vehicles in service. 

In general, passive visual reminder systems illuminate for a period of 5 to 15 seconds. The 

duration varies by manufacturer. Passive systems do not sense if a safety belt is fastened but 

simply illuminate for a predetermined period of time and then shut off. These systems do not 

require a buckle switch or safety belt spool-out sensor in order to operate. 

In Europe, the Swedish heavy truck manufacturers Volvo Trucks and Scania have developed 

enhanced audible reminders that became available as options in their vehicles in 2006. This 

change occurred due to pressure from the European Commission and the Swedish Road 

Administration, which are considering legislation of enhanced audible reminders for large trucks. 

In addition, some large European carriers have requested that the truck manufacturers make 

enhanced audible reminder systems available when purchasing new vehicles. The systems are 

tailored for large-truck applications where they become active (chime) when the vehicle speed 

reaches 30 kph and chime intermittently until safety belts are fastened. 

3.1.3. Comfort Devices 

Currently, the majority of new Class 8 trucks sold in the United States are factory-equipped with 

safety belt tension adjustors more commonly known as the Komfort Latch System (see section 

3.2.2 for a more detailed description of the devices). These devices are sold by the largest 

supplier of safety belts for large trucks. Based on this study, the research team estimated that 50 

percent to 75 percent of the new Class 8 vehicles sold in the United States have the devices. 

These devices are not aftermarket systems. Rather, OEMs may choose to equip all units sold for 

a particular model line with the Komfort Latch. For other models, no Komfort Latch is installed. 

The devices do not appear to be common features in Class 7 and smaller vehicles. Without more 

detailed supplier information, it is difficult to estimate how many of these systems exist in large 

trucks today. It should be noted that the Komfort Latch System is designed to improve comfort 

by allowing the driver to introduce a variable amount of slack into the safety belt system. This 

reduced tension may help drivers achieve a more comfortable fit for safety belts; however, the 

introduction of slack into the safety belt system may also degrade the effectiveness of the 

restraint system.

Seat-integrated safety restraints are another technology that could improve the comfort of safety 

belts for large-truck operators (see section 3.2.2.3 for more detailed discussion). In the United 

States, seat-integrated safety restraints are not sold as standard or optional features in Class 7 or 

Class 8 trucks. However, seat-integrated safety restraints are now being sold as optional 

equipment in a small number of school bus platforms, as reported by vehicle OEMs. Seatintegrated safety restraints are more commonly available in Europe and Australia. A 2005 report 

by the Australian National Transport Commission estimates that 23 percent of 2004 model year 

16 
trucks sold in Australia weighing 3,500 to 28,000 kg have suspension seats and seat-integrated 

safety belts. 

3.2. TECHNOLOGIES REVIEW 

In total, 13 technologies were identified that might increase safety belt use by CMV drivers. This 

section provides a general description of each device including aftermarket cost information if 

available. In addition, a picture of each technology is provided, when available. 

Technologies were identified that promote the use of safety belts: (1) by providing a reminder to 

drivers to buckle up, (2) by facilitating enforcement of safety belt use laws or corporate policies, 

and (3) through improved comfort of safety belt systems. The devices considered are as follows: 

1. Reminder Systems 

• Dash Warning Light/Telltale (Passive System) 

• Intermittent Dash Warning Light/Telltale (Active System) 

• Audible Reminder (Passive System) 

• Enhanced Audible Reminder (Active System) 

• Transmission Interlock System 

2. Comfort Strategies 

• Safety Belt Tension Adjustors 

• D-Ring Height Adjustors 

• Seat-Integrated Safety Restraint System 

• Safety Belt Covers 

3. Enforcement Strategies 

• Brightly Colored Safety Belts 

• Onboard Data Recorders 

• Exterior Safety Belt Use Indicator 

• Driver Monitoring Stickers 

3.2.1. Reminder Strategies 

Dash Warning Light/Telltale (Passive System) 

This device would provide a visual reminder to drivers to buckle up at the start of each trip. A 

passive system similar to those in many passenger vehicles today would illuminate if the ignition 

were placed in the “on” position and would shut off after a predetermined time period had 

passed. Currently, a number of CMVs are equipped with systems that illuminate for periods 

between 5–15 seconds. The telltale most often used in vehicles equipped with visual systems is a 

graphic showing a belted occupant. For passenger vehicles, FMVSS 208 requires that a visual 

reminder system illuminate for at least 4 seconds, but no more than 8 seconds, when the vehicle 

ignition is placed in the “on” position (Federal Register, 1974). This requirement does not apply 

to vehicles weighing 10,001 pounds or more. No definitive cost data were available for this 

17 
technology; however, manufacturers have estimated that the technology might cost $5–$10 to 

implement in a vehicle not equipped with the system. 

Intermittent Dash Warning Light/Telltale (Active System) 

An active dash warning light would operate similarly to the simple dash warning light or telltale 

system; however, the system would continue to illuminate or flash until safety belts were 

fastened. Unlike the baseline technology described above, this system would require sensing of 

safety belt use and would not turn off after some nominal time period. These enhanced systems 

currently exist in most passenger vehicles and in some medium-duty trucks. As presented in 

section 4.1 of this report, these systems are not commonly installed in Class 7 and 8 vehicles. 

The system would require sensors to determine if the safety belt was fastened. This could be a 

simple buckle switch or a safety belt payout sensor to identify if a safety belt has been extended 

from its stowed position. In addition, added wiring and some logic programming would be 

required. The added cost of this technology is estimated to be $75; it is available as an option 

from some large-truck manufacturers. 

Audible Reminder (Passive System) 

This device would provide an audible reminder to drivers to buckle up at the start of each trip. A 

passive system would chime or sound once the ignition is placed in the “on” position and shut 

off after a predetermined time period, much like the passive visual reminder system previously 

described. For passenger vehicles, FMVSS 208 requires that an audible reminder system sound 

for at least 4 seconds but no more than 8 seconds when the vehicle ignition is placed in the “on” 

position. This requirement also does not apply to vehicles with a GVWR of 10,001 pounds or 

more. Within a large truck, the sound created by this system must be distinguishable from other 

audible systems that are often active at vehicle startup. The duration of the sound should be 

tailored to the unique conditions within each vehicle. No definitive cost data were available for 

this technology; however, manufacturers have estimated that the technology might cost $5–$10 

to implement in a vehicle not equipped with the system. 

Enhanced Audible Reminder (Active System) 

An enhanced audible reminder system would provide an audible alert for an extended period of 

time beyond that of the passive system. These devices would monitor safety belt use actively 

through buckle switches or safety belt payout sensors, and continue to provide the driver with an 

audible alert until the safety belt is fastened. The features of an enhanced system could be 

tailored, based on user preference, so that the frequency and intensity of a chime could be varied. 

In addition, due to the unique operating environment for large trucks, the system might be 

tailored to activate at a predetermined speed level and during operation of the vehicle while 

moving forward. One implementation of the system in vehicles manufactured by Ford, for 

passenger vehicle applications, chimes for 6 seconds every 20 seconds for up to 5 minutes if a 

front-seat occupant is present and unbuckled while the vehicle is in motion (Farmer, 2003). 

Other manufacturers, like Saab, have implemented systems in which intensity increases as travel 

speed increases. For drivers who always use safety belts, this system would not activate and 

could go unnoticed. The audible reminder is intended to remind front-seat occupants to buckle 

up in case they forget. Based on a BCA performed by the Australian government for passenger 

18 
vehicles, the aftermarket cost for such a system is estimated to be $110 per vehicle (including 

buckle switch and wiring, onboard computer programming with safety belt use logic, and 

integration with an existing vehicle chime). It should be noted that some manufacturers have 

implemented functionality where drivers can temporarily or permanently disabled enhanced 

audible reminder systems. Disabling the optional Enhanced Audible Reminder System does not 

affect the functionality of the 4- to 8-second basic audible reminder that is required by FMVSS 

208 in all passenger vehicles with a GVWR of 10,000 pounds or less. 

Interlock Systems 

Interlock devices have been used in the past to disable certain vehicle features if safety belt 

systems are not in use. Ignition interlocks prevent the engine from operating if the driver is 

unbelted. Transmission interlocks prevent the driver from putting the vehicle into a forward gear 

if the driver is not belted. Entertainment system interlocks prevent the use of certain onboard 

electronics, including the stereo system, CB radio, or other electronics if the safety belts are not 

fastened. These devices each require sensors that detect safety belt use, and they also require 

programming to interact with other electronic devices. As described previously, a requirement to 

include ignition interlocks in passenger vehicles is forbidden by law due to the unsuccessful 

implementation of the systems in 1974 model year passenger cars. Currently, alcohol ignition 

interlocks are frequently used to prevent drivers from starting their cars when their breath alcohol 

concentration is at or above a predetermined level. This suggests that the technology to interface 

with vehicle electronics is available for implementation. 

3.2.2. Comfort Strategies 

Safety Belt Tension Adjustors 

Safety belt tension adjusters are designed to allow users to introduce some slack into safety belts 

to reduce abrasion and irritation against the upper body. The most readily available device, 

known as the Komfort Latch System, is rigidly attached at the vehicle B-pillar where the D-ring 

is fastened (Figure 1). The safety belt system is threaded through the plastic clip and can be 

locked at any position along the safety belt. In order to reduce the contact forces between the 

safety belt and the occupant’s upper body, a driver can introduce slack into the safety belt 

system. The system is activated by pulling out some desired amount of safety belt webbing and 

cinching the clip at any desired location. Ideally, the Komfort Latch should be fastened so that 

there is enough slack to eliminate safety belt contact forces, but the safety belt is close enough to 

occupants to effectively restrain them in the event of a sudden maneuver or a crash. The system 

can be disengaged by yanking on the system, and it will disengage automatically during a 

collision event once extended beyond the locked level. The system does not affect the activation 

of web-lockers or load limiters. The only difference in performance will stem from the 

introduction of additional slack to the safety belt system. Based on information supplied by the 

manufacturer, the Komfort Latch System has been sold with new vehicles and safety belt 

systems in more than 90 percent of CMVs sold in the United States for the past four to five 

years. 

19 
Figure 1. Komfort Latch System 

As previously discussed, these systems are factory installed. The devices are integrated with the 

safety belt system and are not available as an aftermarket device. Vehicles are either equipped or 

not equipped by model line. If one vehicle unit is equipped with the device, all others within the 

same make, model, or model year will likely be equipped with the Komfort Latch System as 

well. 

The Sliding Comfort Latch is the second generation of the Komfort Latch device. Unlike the 

Komfort Latch, the Sliding Comfort Latch System (Figure 2) is designed to introduce a 

predetermined amount of slack into the safety belt so that the user does not have to. With the 

first-generation Komfort Latch System, it is possible that a driver may introduce too much slack, 

which may defeat the purpose of the device in adequately restraining him or her in the event of a 

crash or a sudden maneuver. The device locks at a point based on the occupant’s amount of 

movement once the system is first activated. In order to activate the device, a simple “on” switch 

is pushed. Unlike the previous generation, the new device will only temporarily disengage during 

extended movements, such as adjusting the radio or reaching for distant objects, yet will reengage once the occupants return to their initial seating position. A safety belt system equipped 

with the original comfort latch may become uncomfortable or annoying to the driver after 

movement if the system does not actively reset the device. This may lead to the overall 

perception that the safety belt system is uncomfortable, and possibly lead to nonuse of safety 

belts. Device costs are estimated to be about $35 per unit; however, retrofitting vehicles with the 

Komfort Latch requires complete replacement of the retractor, safety belt webbing, D-ring, and 

buckle system, as it is not sold separately from the whole safety belt system. The cost of 

complete replacement is $135–$155. 

20 
Figure 2. Sliding Comfort Latch System 

Adjustable D-Ring 

In order to optimize the geometry of safety belts to fit a wide variety of occupant sizes, some 

passenger and commercial vehicles are equipped with adjustable D-rings (Figure 3). The height 

of the top anchorage point can be adjusted so that the take-off point (point where the safety belt 

last contacts the occupant on the shoulder) can be optimized for comfort. If the D-ring is placed 

too low, the safety belt will come in contact with the top portion of the shoulder and in extreme 

cases wrap over the top. A D-ring that is placed too low may cause safety belts to fall over the 

shoulder joint or upper arm. This may occur for very tall drivers with low D-rings. Conversely, 

occupants of small stature may find the safety belt cutting across their necks and faces if the Dring location is set too high. 

In order to accommodate the introduction of an adjustable D-ring, the vehicle B-pillar must have 

sufficient structure to accommodate the change. If the vehicle structure is sufficient, the 

incremental cost for the height adjustment system is about $30 per unit. 

Figure 3. Adjustable D-Ring 

Source: Photo courtesy of IMMI, Inc. 

21 
Seat-Integrated Safety Restraints 

Seat-integrated safety restraints (Figure 4) operate much like traditional safety belt systems; 

however, the upper D-ring and lower anchorage points are attached to the seat structure itself. 

The benefit of these systems would be to reduce the relative motion that occurs between 

suspended seats found in many large trucks and fixed anchorages traditionally mounted on the 

vehicle B-pillar and floor. With an integrated restraint, the safety belt system would travel 

vertically with the seat structure as it moves up and down and fore and aft during travel. Because 

the motion of a large-truck cab is substantially different (and larger in amplitude) than a 

passenger car or even an SUV or pickup, these systems could reduce contact forces and rubbing 

while driving. These devices are currently offered in many passenger vehicles and commercial 

vehicles. European manufacturers are offering seat-integrated safety restraints in their vehicles in 

order to improve safety belt fit and comfort for drivers. Seat-integrated safety restraint costs vary 

considerably; they range from $750–$1,000 per seat. 

Figure 4. Seat-Integrated Three-Point Restraint 

Source: Photo courtesy of Ford Motor Company. 

Safety Belt Covers 

Safety Belt Covers are aftermarket devices designed to reduce rubbing and irritation between the 

safety belt and the occupant. Most systems are either sewn in place or attached by using Velcro. 

The device costs $20–$30 per unit. 

NHTSA does not recommend any aftermarket technology be added to a safety system as it may 

compromise its intended function. Safety belt covers change the interface between the belt and 

the occupant and may result in unfavorable kinematics of the occupant during a crash. 

22 
3.2.3. Enforcement Strategies 

Brightly Colored Safety Belts 

Brightly colored safety belts are a potential enforcement strategy (Figure 5). These safety belts, 

currently in use by some fleets, would be bright orange, yellow, or green. They would be highly 

visible to law enforcement and/or DOT personnel so that there would be little question whether 

the systems were being worn. The bright color would suggest to drivers that enforcement of 

safety belt use and detection of nonuse would be easier for designated officials (i.e., at inspection 

stations or by police). 

Figure 5. Example of a Brightly Colored Safety Belt for CMV Operators 

The incremental cost of this technology is estimated to be $12 over the base (noncolored) safety 

belt. If the entire safety belt system is purchased and installed (including retractor, D-ring, buckle 

system, and safety belt webbing) the estimated cost is $95–$120. 

Onboard Data Recorder 

Onboard data recorders may be an effective strategy to increase safety belt use if corporate safety 

personnel or police make use of the data. Currently, devices exist for CMVs to track location, 

conduct vehicle diagnostics, and plan routes. Additional functionality can be added to these 

systems to monitor and record safety belt use status. This information can later be downloaded or 

queried by designated individuals to evaluate whether a safety belt was being worn at a particular 

time or to understand during what percentage of travel time over a certain period that the safety 

belt was worn. The effectiveness of such systems relies on the perception that the data will be 

downloaded and used. 

23 
The estimated cost of an onboard data recorder is $2,000–$4,000 per vehicle. If safety-belt-use 

recording functionality is added to an existing data recorder (recording other data elements), the 

anticipated price increase might be $200–$300 per vehicle. 

Exterior Safety Belt Use Indicator 

The exterior safety-belt-use indicator light is a concept that could be effective in increasing 

safety belt use by CMV drivers. This device would allow law enforcement or vehicle inspectors 

to easily identify if a driver is unbelted. This concept was suggested by stakeholders interviewed 

during the study. One implementation of such a system would be to engage vehicle flashers if 

safety belts were not securely fastened. This approach was explored by the Australian 

government and was identified as a complex and costly option that would likely increase safety 

belt use. No cost estimates are currently available for this device. 

Safe Driving Bumper Stickers 

The use of safe driving bumper stickers is one approach that could facilitate enforcement of 

safety belt use laws and policies. Currently, stickers read by other motorists, such as: “How’s my 

driving? Please call 1-800...,” are commonly used to alert fleet safety personnel that their drivers 

may be operating in an unsafe manner. The same approach could be used where other motorists 

might report that drivers are not belted while driving. The use of these stickers might help drivers 

to realize that there is some chance that they will be caught and reprimanded if they are spotted 

driving in an unsafe way or driving while unbelted. A number of private companies offer 

services where they issue stickers for each truck, screen, and record call information for each 

company and report statistics to company officials. The cost of sticker purchase and service is 

$10–$20 for each vehicle annually. 

24 
4. STAKEHOLDER AND DRIVER PERSPECTIVES

The following summarizes the perspectives of industry stakeholders and drivers regarding each 

device considered: 

1. Reminder Systems 

• Dash Warning Light/Telltale (Passive System): Stakeholders felt that passive visual 

systems that light for a short period and go out on their own would be ineffective in 

increasing safety belt use. 

• Intermittent Dash Warning Light/Telltale (Active System): Stakeholders felt that an 

intermittent dash warning light would be effective for some drivers, particularly during 

nighttime scenarios. Stakeholders felt the annoyance of an audible strategy would be 

more effective. 

• Audible Reminder (Passive System): As with the passive dash warning light system, 

stakeholders felt that a passive audible device could be easily ignored. This is especially 

true in large trucks where a number of warnings (visual and audible) are activated at 

vehicle startup. An audible chime could easily be lost among other alerts. 

• Enhanced Audible Reminder (Active System): The enhanced audible reminder was 

favored as a potentially effective strategy. Stakeholders commented that the 

characteristics of such a system should be tailored to large-truck applications. 

• Transmission Interlock System: The transmission interlock device was not highly 

favored. Stakeholders cited past experiences with such devices in passenger vehicles and 

were concerned that a malfunctioning system might prevent a driver from doing his or 

her work. 

2. Comfort Strategies 

• Safety Belt Tension Adjustors: Stakeholders favored these devices, indicating that they 

are one of the few systems that could help drivers improve the comfort of safety belts; 

however, additional driver awareness is necessary to ensure increased safety belt wearing 

rates. 

• D-Ring Height Adjustors: Many stakeholders acknowledged that height adjustors might 

improve safety belt fit and overall comfort, but improved driver awareness would be 

necessary before the devices would lead to improved safety belt use rates. In addition, the 

device would only address part of the safety belt comfort issue (i.e., geometry, not the 

rubbing of safety belts). 

• Seat-Integrated Safety Restraint System: Stakeholders favored the concept of seatintegrated safety restraints; however, they felt that the technology requires additional 

comfort evaluation and might be a long-range solution. 

• Safety Belt Covers: Few stakeholders saw benefit in such systems. Some identified that 

comfort relates more to geometry of systems, and that a safety belt cover would not bring 

about improvement in this area. 

3. Enforcement Strategies 

• Brightly Colored Safety Belts: Brightly colored safety belt systems were favored by 

stakeholders as a cost-effective strategy that could make a considerable difference. 

25 
• Onboard Data Recorders: Onboard data recorders were strongly supported by all fleet 

managers and trade organizations. They felt that with the introduction of electronic 

onboard data recorders (EOBDRs) into trucks to log hours of service, this solution might 

hold promise; however, implementation of an electronic recorder for the purpose of 

recording safety belt use did not seem worthwhile. 

• Exterior Safety Belt Use Indicator: This system was thought to be potentially effective; 

however, it was perceived as potentially unfair to drivers. 

• Driver Monitoring Stickers: Stickers were thought to be a plausible solution but were not 

highly favored as the ideal solution. 

4.1. INDUSTRY PERSPECTIVES 

Discussions were conducted with industry stakeholders, many of the members of the CMV 

Safety Belt Partnership, to gain insight into the safety-belt-use issue and to seek feedback 

regarding the viability and practicality of the various technologies described in Chapter 3. 

Industry perspectives were gathered during discussions with various representatives from the 

following organization types: 

• Vehicle OEMs 

• Restraint and aftermarket device suppliers 

• Insurance organizations 

• Commercial motor vehicle fleet safety managers 

• Trade associations and government personnel 

A summary of key responses by the stakeholders is provided in the following six topics. 

4.1.1. Topic 1: Increasing Safety Belt Usage by CMV Drivers 

• A trade organization and fleet safety manager reported similar opinions that large, wellmanaged fleets could successfully address safety belt use through enforcement of 

corporate policies. However, smaller fleets without a well-enforced corporate policy 

would likely respond to technologies facilitating enforcement by inspectors and police to 

increase safety belt use. 

• A government representative indicated that some drivers may not have knowledge of the 

potential benefits of safety belts. Education will help, but must be delivered in a concise 

format that drivers can relate to. An education campaign should be assembled and widely 

distributed to dispel myths related to safety belts. 

• A fleet manager suggested that money out-of-pocket is a serious incentive for drivers. 

Enforcement of company policies that could impact employment would be effective, and 

the threat of fines from police or inspectors for nonuse of safety belts would also help. 

• A trade organization representative indicated that issues of safety belt use differ 

considerably with owner-operators as compared to private companies, unless the owneroperators are personally committed to their own safety, as large-fleet safety managers are. 

26 
• An industry representative suggested that owner-operators could possibly be reached 

through improved public awareness and education, where graphic materials and serious 

messages might be the most effective. 

• A fleet safety manager suggested that he has noticed a shift in safety culture whereby 

younger drivers, who have been raised in an environment where safety belts are required, 

are beginning to take positions previously held by older drivers who are not habitual 

safety belt wearers. 

• As suggested by a trade organization representative, perhaps FMCSA or other interested 

organizations can offer a model safety training template for companies that could easily 

be adapted to company specifics. Using this presentation, a company can easily and 

accurately educate new and existing drivers on the utility and correct use of safety 

devices. 

4.1.2. Topic 2: Comfort Issues 

• A vehicle OEM reported that he believes that there may be comfort issues for certain 

segments of the CMV driver population, but he also indicated that few scientific data 

exist describing driver anthropometry and characteristics of safety belts in trucks that 

make them “uncomfortable.” 

• A vehicle manufacturer identified that upper D-ring height is an important aspect of 

shoulder safety belt comfort, yet there is little demand from vehicle purchases for the 

installation of these devices. 

• Multiple stakeholders suspected that drivers cite discomfort due to past history or as an 

excuse. Many stated that if users were compelled to wear safety belts, even for a short 

period of time, they would likely change their opinions and even develop the habit of 

wearing the safety belt. 

• A restraint manufacturer cited that nuisance lockups are one source of discomfort from 

safety belt systems; however, current safety belt design requirements and the harshness of 

the ride make complete elimination of nuisance lockups impossible. Yet another restraint 

manufacturer indicated that accidental lockups seem to be reducing in frequency due to 

improved safety belt design. 

• Several stated that the safety belt just takes getting used to, and that the basic 

configuration is uncomfortable for only a small minority. 

4.1.3. Topic 3: Technology Types 

Audible Reminder Systems 

• A government stakeholder suggested that although many have stated that they would 

attempt to disable enhanced audible reminder systems, many part-time safety belt users 

would respond to systems by buckling up. An estimated 10 percent to 15 percent of 

drivers might truly be habitual nonusers, but little can be done to reach these people. 

• An OEM representative indicated that for some applications, a reminder system may not 

be appropriate; for example, for drivers who make frequent stops. 

• Multiple stakeholders supported this technology, indicating that the approach has been 

widely successful in the passenger vehicle world and would likely be successful in trucks. 

27 
• A stakeholder suggested that adding an additional audible warning that is passive (sounds 

for a short period and shuts off) may not be effective because of the large number of 

warnings and buzzers that already exist in large trucks. Field testing must be performed 

to put together an optimized system that would be recognized as a warning for safety 

belts and accepted by users. 

• Manufacturers indicated that optional equipment has already been developed that calls 

for buckle switches/sensors, wiring of buckle to onboard systems, and programming logic 

to interpret safety belt use status by onboard computers. These systems would be 

necessary to support an enhanced audible reminder system. 

Visual Reminders 

• An OEM representative indicated that a visual system will likely impact nighttime drivers 

by reminding them to buckle up; however, this representative felt that a driver who is 

adamant about not wearing the safety belt could likely adapt to the light system. This 

stakeholder felt that an audible chime could be a more significant annoyance. 

• A government stakeholder suggested that visual warnings would be more effective if they 

flashed rather than illuminated continuously. User perspectives should be collected using 

actual on-road driving scenarios. 

Electronic Onboard Data Recorder 

• Fleet safety managers identified that EOBDRs would be extremely valuable to enforce 

safety-belt-use policies, but currently proposed regulations might only require the 

installation of devices owned by the poorly performing companies with regard to safety. 

An industry-wide deployment would likely be more effective, but the economic burden 

that this would place on smaller fleets might not be reasonable. 

• An OEM representative suggested that a system might be effective if a roadside inspector 

could easily see the information when he inspects the hours-of-service logs. Data could 

be made available using a printout or viewed on the EOBDR screen by inspectors. 

• An insurance representative indicated that options like EOBDRs require follow-through 

at the company’s headquarters. The data would be only as effective as the management is 

in using the data to monitor drivers. The stakeholder stated that the introduction of 

technology into vehicles does not ensure that it is used. 

• A fleet safety manager indicated that many fleet owners fear that drivers will rebel 

against a recorder; however, evidence shows that few object to EOBDRs once they are in 

place, due to the time-saving benefits of the systems. 

• A government representative felt that vehicle fleet owners have the right to add any 

technology they choose and should not compromise the safety of their drivers to 

accommodate drivers’ wishes. 

• Insurance advocates indicated that they are in favor of a company making use of data 

recorders to reward good behavior and help poor-safety performers to drive more safely. 

This concept suggests that fleet management could take on this task and it would be 

looked upon favorably by insurance companies. 

• A truck fleet owner has the right to use data to protect the lives and well-being of their 

drivers and to ensure that their drivers are operating safely. 

28 
Brightly Colored Safety Belt Systems 

• Two fleet safety managers have purchased and implemented brightly colored safety belts 

in their fleets and feel that these devices have made a difference in their drivers’ 

behavior. Drivers fear enforcement by police (small fleet) and by corporate officials 

(large fleet). 

• An insurance representative suggested that the success of brightly colored safety belts 

relies on the fact that specific people are looking for the safety belts, namely, police and 

company personnel. Others believe that the threat of enforcement also has a significant 

impact. 

Interlock Technologies 

• Stakeholders were reluctant to support interlock technologies due to the possibility that 

drivers would be unable to perform work if the device failed. 

Safety Belt Tension Adjusters 

• Two manufacturers (one OEM and one restraint manufacturer) agreed that a safety belt 

system with a safety belt tension adjustor would perform better if a pretensioner were 

installed; however, the cost of these systems might prevent them from being voluntarily 

introduced. 

• All stakeholders from OEMs indicated that the Komfort Latch is available in the majority 

of their Class 8 vehicles being sold, and the manufacturer of the tension-reducing system 

(Komfort Latch) reports that they are sold with 90 percent of new Class 8 vehicles. 

• An OEM stakeholder suggested that the use of the Komfort Latch was an acceptable 

interim solution until seat-integrated safety restraints were introduced. Negative 

stakeholder opinions were based on the introduction of slack into safety belts, which is 

known to degrade performance. 

Seat-Integrated Safety Restraints 

• Manufacturers indicated that the addition of seat-integrated safety restraints would 

require additional engineering for vehicle structures to meet frontal crash test 

requirements; however, manufacturers indicated that the redesign would be technically 

feasible. 

• All OEM stakeholders indicated that seat-integrated safety restraints appear to be a good 

idea, but the only current application in the United States is in buses. 

• Within the current bus applications, one OEM indicated that some complaints regarding 

seat-integrated safety restraint comfort have been raised because current systems are 

optimized for 50th percentile drivers. Development is underway to design seat-integrated 

safety restraints with variable upper anchorage heights to deal with this problem for 

smaller drivers. 

Adjustable D-Ring 

• A manufacturer indicated that adjustable D-ring systems were offered as an option for 

many years; however, the company chose to stop offering this because so few customers 

purchased the device. 

29 
• A restraint manufacturer suggested that safety belt comfort is a direct function of optimal 

seat and D-ring geometry. He expressed the thought that an adjustable D-ring is a 

promising device to achieve comfortable geometry, but few drivers understand or make 

use of the systems. 

• A fleet safety manager indicated that they do not have or offer any training to instruct 

drivers on safety belt adjustment for optimal comfort. The representative suggested that 

his organization does not have any clear guidelines to offer and also pointed out that only 

a handful of his vehicles are equipped with an adjustable D-ring system anyway. 

4.1.4. Topic 4: Integration and Footing the Bill 

• A trade organization representative and a number of vehicle manufacturers suggested that 

safety technologies are not likely to be added without demand from purchasers or 

regulatory requirements for their installation. This is the case because truck pricing is 

very cost-competitive. 

• Very few manufacturers will voluntarily begin adding a new device, due to the added 

cost. Additional technology would put them at a competitive disadvantage. However, if a 

requirement were in place, manufacturers would not complain. 

• A private fleet installed brightly colored safety belts and found their inclusion in vehicles 

made a considerable difference, along with good safety practices in observing drivers. 

Costs were absorbed by the company to retrofit some vehicles in the 500+ vehicle fleet, 

while other systems were introduced during new vehicle phase-in. Another fleet safety 

manager indicated that he purchased new bright orange safety belts at an added cost of 

$12 per unit for his 17-vehicle fleet. Retrofitting vehicles would cost $110 per truck. 

• Manufacturers indicated that all technologies under consideration are technically feasible 

and could be easily added if there was regulatory or consumer demand for the products. 

One manufacturer suggested that recent CAFE (corporate average fuel economy) 

requirements will likely lead to faster introduction in new trucks, so that integration of 

new technology in these vehicles could occur very quickly. 

• Insurers indicated that they are not likely to offer rate incentives for the implementation 

of a safety belt technology. Rather, insurance rates are typically based on past 

performance in terms of crash involvement, injuries, and fatalities. 

• Insurers look more favorably on fleets that have put emphasis on safety in general rather 

than implementing a single device. A rate reduction might be factored in if a company 

demonstrated a total commitment to safety. 

• As indicated by one insurer, large fleets often purchase insurance with large deductibles 

($1M, $2M, etc.), so their insurance premiums remain low. For this reason, crash costs 

due to property damage and injury are often first absorbed by the trucking companies. 

• A trade organization suggested that any company that is not willing to implement a 

mandatory safety-belt-use policy is not serious about safety. 

• Owner-operators should have to follow safety guidelines set by the companies they work 

for. There is an opportunity at the contracting phase to include mandatory use of safety 

belts in the contract. 

30 
4.1.5. Topic 5: Corporate Safety Belt Policy 

• A small fleet safety manager (fewer than 25 trucks) has successfully implemented a 

program known as Pay for Performance in which financial rewards are offered quarterly 

for good performance. Drivers are rewarded with a $0.02 increase per mile for any 

quarter where no violations occurred. If they receive a citation or are involved in a 

preventable crash, a portion of the reward is removed. At the end of each year, rewards 

are given for good safety performance throughout the year. This fleet safety manager 

strongly supported using EOBDR information (regarding safety belt use) in the future as 

one factor used to offer rewards. 

• A fleet manager whose drivers are primarily hauling hazmats described their safety-beltuse policy as a last-resort policy where any driver who is cited, caught, or involved in a 

collision while unbelted is fired. The policy appears to be very effective; however, 

multiple strategies were simultaneously applied (added education and bright safety belt 

strategies) to bring about the change in behavior. This change was made after a number 

of serious injury crashes occurred in which safety belts were not used. 

• A fleet safety manager explained that they used a “three strikes, you’re out” policy in 

which drivers are fired if they are involved in or cited for more than three safety-related 

violations within a two-year period. These instances include being in a preventable crash, 

receiving a ticket/DOT citation of any kind, or being spotted by management or other 

personnel while unbelted or involved in any other unsafe driving acts. This fleet manager 

admitted that management of this company rarely performed dedicated observations or 

cited drivers for observed unsafe behaviors. 

4.1.6. Topic 6: Other Strategies to Increase Safety Belt Use by CMV Drivers 

• A fleet safety manager described a recent statewide policy that requires certification of 

drivers for homeland security applications before a commercial driver’s license (CDL) is 

issued, and suggested that a safety module could be added during the online certification 

process. This approach might work if an online or written safety belt course were also 

required before allowing a CDL renewal. 

• Multiple stakeholders, including trade association representatives and insurance 

representatives, stated that they believed that drivers’ wearing of safety belts is the 

responsibility of the fleet owner/manager, and that companies should implement any 

strategy or technology they feel would protect the well-being of their drivers, regardless 

of any perceived threat of driver disapproval. 

• A trade organization representative suggested that inconspicuous cameras or observations 

from an inspection station might help to identify drivers before they buckle up. The 

perception that higher levels of enforcement exist might result in increased safety belt 

use. 

• Two fleet safety managers indicated that they successfully use driver safety stickers 

(How’s My Driving? Please Call 1-800-....) to monitor driver behavior. If a concise 

message could be written to request a call if drivers are spotted driving unbelted, this 

might also help to promote safety belt use. 

31 
4.1.7. Stakeholder Discussion Summary 

The stakeholders collectively emphasized the importance of CMV drivers wearing safety belts. 

For the most part, they showed a common perspective on all of the issues raised. In general, the 

participants agreed that more education about the benefit of safety belts and the safety belt 

technologies that are currently available or in use would increase the safety belt use rates. It was 

felt that large and well-managed fleets could increase safety belt use with enforcement, but that 

smaller fleets would likely find it necessary to rely on inspectors and police. In general, 

stakeholders indicated that the common reason for not wearing the safety belt (comfort issue) 

was based on past history or that it was used as an excuse. 

Several technologies were discussed with the stakeholders and the majority of the opinions were 

similar. They indicated that the audible reminder worked well in passenger vehicles, but it would 

likely not be as effective for drivers who make frequent stops. Visual reminders were thought to 

be more effective at night and perhaps even better if they flashed when activated. An industrywide deployment of the EOBDR would be more effective, but the economic burden on smaller 

companies would probably be unreasonable. This technology was favored by insurance 

companies. 

Brightly colored safety belts are currently used in some fleets, and it is believed that the fear of 

enforcement makes this device effective. Interlock technologies were unfavorable because a 

driver may not be able to carry on with work if the device fails. Safety belt tension adjusters are 

currently widely available, but the introduction of too much slack is a concern. Manufacturers 

indicated that seat-integrated safety restraints would require additional testing to meet frontal 

crash test requirements. The adjustable D-ring is a favored device, yet there is no training for 

drivers to receive optimum comfort. 

The integration of technologies to increase safety belt use in CMVs and the financial concerns of 

doing so were discussed. It was indicated that manufacturers are not likely to add safety belt 

technologies unless there is a demand from purchasers or unless regulatory requirements exist 

that would keep pricing competitive. The discussion also indicated that all of the technologies 

discussed were technically feasible. Insurers indicated that they are not likely to offer incentives 

for safety belt technology, as their incentives are typically dependent upon past performance 

records. However, if safety belt reminder systems or other approaches begin to have a 

measurable positive safety impact, it would be possible that a reduction in insurance costs might 

be realized with the introduction of this safety feature. 

Rewards and penalties are both used in corporate safety-belt-use policy. Financial rewards are 

offered quarterly for good performance in one participant’s company, whereas another company 

will fire an employee who is not belted when involved in a collision; yet another company gives 

the employees three strikes before they are terminated for not wearing their safety belts. 

Discussion participants were asked for other strategies to increase safety belt use, and the most 

common response was to offer more education about safety in general and the safety belt 

technologies offered in their fleets. Bumper stickers asking for violations to be reported and 

inconspicuously placed cameras were suggested as methods of enforcement. Numerous 

32 
stakeholders believe that wearing a safety belt is the responsibility of the fleet owner/manager, 

regardless of the threat of driver disapproval. 

4.2. DRIVER PERSPECTIVES 

Based on information gathered during the literature review and through interaction with industry 

stakeholders, several promising technologies were selected for further review. To better 

understand opinions of drivers regarding the practicality and potential usefulness of these 

devices, the research team conducted various discussions with drivers. The discussions were held 

to evaluate aspects of new safety belt technologies such as perceptions of proposed technologies, 

including the benefits, unforeseen pitfalls, and the acceptance or rejection of these by CMV 

drivers. 

Discussions were conducted with CMV drivers regarding current safety belt use and nonuse, and 

safety belt technologies. Both nonusers of safety belt and safety belt users were involved in these 

discussions. The drivers talked about their beliefs on the efficacy of safety belts, personal safety 

belt use (current and past), safety belt comfort, seat enforcement, and personal freedoms. Also 

discussed were the following: 

• Safety belt tension adjustor: Komfort Latch 

• Seat-integrated safety belts (three-point) 

• Seat-integrated safety belts (four-point) 

• Enhanced audible reminder 

• Dash warning light 

• Vehicle transmission interlocks 

• Entertainment system interlocks 

• Heating and cooling system interlocks 

• Onboard data recorders 

• Exterior safety belt use indicator light 

• Brightly colored safety belts 

• Safety belt monitoring by transponder at weigh stations 

The topics of discussion varied. The key findings, observations, and impressions received 

regarding the various issues are presented as follows: 

1. Improving Safety with Safety Belts 

2. Safety Belts in CMVs versus Passenger Vehicles 

3. When Safety Belts Are Used 

4. Why Safety Belts Are Used 

5. Safety Belt Comfort 

6. Safety Belt Enforcement 

7. Twelve Technologies to Increase Safety Belt Use 

33 
4.2.1. Topic 1: Improving Safety with Safety Belts 

There is a perception among nonusers of safety belts that wearing safety belts in trucks can be 

potentially harmful. Nonusers of safety belts provided anecdotal stories of people who would 

have been killed had they been wearing a safety belt. Another prevalent perception is that 

wearing a safety belt would prevent a driver from being able to quickly move out of harm’s way 

if his or her load was shifting or if a crash was impending. They felt there would be sufficient 

time to move to a safer portion of their cab or jump safely out of the vehicle if unbelted. There 

are also fears of being trapped in rollovers and intrusion from behind. 

Among the safety belt users, most agreed that safety belts make you safer. Two reported being 

saved by safety belts and one reported starting to wear a safety belt after seeing another driver 

thrown from his truck, which rolled on top of him. However, many of the consistent safety belt 

users felt that there were situations in which safety belt use could hurt a driver. 

Observations and impressions on whether safety belts improve safety include the following. 

Nonusers of Safety Belts 

• There is an overall feeling that safety belts would be useful in about 50 percent of 

crashes, and that this varies by accident. 

• The biggest driver concern during crashes is intrusion, where the engine, steering, or dash 

could get pushed into the compartment. 

• Personal stories were told identifying experiences in which people survived with no 

safety belt. 

• There is an overall belief that the safety belt increases the chances of injury. 

Safety Belt Users 

• There is a fear that the safety belt might injure the chest. 

• An unbelted driver who had been in a rollover was ejected from the cab and was pinned. 

He wondered if not wearing the safety belt had saved him or hurt him. 

• There is a perception that if a truck rolls to the right, a safety belt will help. If it goes to 

the left, the safety belt could cause injury. 

4.2.2. Topic 2: Safety Belts in CMVs versus Passenger Vehicles 

Drivers stated that the air seats in a truck cab move up and down and front to back. The safety 

belt is usually fastened to the back of the cab and therefore causes rubbing against the neck. 

Unlike in a passenger vehicle, normal driving over rough roads and braking causes the safety 

belts to lock. Drivers also said that safety belts are hot to wear and become uncomfortable after 

they are worn all day. 

4.2.3. Topic 3: When Safety Belts Are Used 

Some of the nonusers wear safety belts some of the time. When asked, almost all say that they 

wear the safety belts when they go through weigh stations. Others buckle up in bad weather or 

heavy traffic. Some buckle up in their personal cars to be an example for their children. 

34 
4.2.4. Topic 4: Why Safety Belts Are Used 

Some safety belt users said that they use safety belts only because it is the law. Others believed 

in the safety effects of safety belts. They also mentioned that it was simply a habit with them. 

The general feeling is that safety belts are worn to avoid traffic tickets, to avoid points on the 

CDL (which increases insurance costs), and to avoid company fees. 

4.2.5. Topic 5: Safety Belt Comfort 

Although some passenger vehicle drivers complain that safety belts are uncomfortable, the safety 

belts have improved. As the laws and enforcement have become stricter, safety belt use rates 

among passenger vehicle drivers have moved from 61 percent in 1996 to 81 percent in 2006. The 

overall rate for CMV drivers was 59 percent in 2006. One question is whether safety belts in 

CMVs are uncomfortable and whether this is the defining reason for nonusage of safety belts by 

CMV drivers. 

Nonusers of safety belts complained about comfort, although personal freedom was also 

mentioned. 

Observations and impressions on reasons the drivers dislike safety belts include the following. 

Nonusers of Safety Belts 

• Safety belts are uncomfortable for women and shorter people. 

• It is hard to move around and there is a concern to be comfortable on a long haul. 

• Safety belts are confining and restricting. 

• Rubbing from bouncing is a factor in not wearing safety belts. 

• The safety belts are too tight around the belly. 

• Safety belts rub on the neck. 

• Soreness results from wearing the safety belt. 

• Personal freedom is violated. 

35 
Safety Belt Users 

• In general, the safety belt users reported that the safety belts rub against their necks. 

• When the Komfort Latch was used, it was pulled out to varying degrees. One person 

pulled it out just enough not to hit the steering wheel. One said that once he discovered 

the Komfort Latch, wearing a safety belt became much more comfortable. 

4.2.6. Topic 6: Safety Belt Enforcement 

Getting a ticket is a constant concern for most drivers. However, getting a safety belt violation is 

much less serious than getting a moving violation. Truckers reported trying to talk their way 

down to a safety belt violation, sometimes unbuckling the safety belt to give the officer the 

possibility. The safety belt enforcement was seen by many as a way for police agencies to make 

money. Users and nonusers felt that safety belt use was enforced and all of them knew to buckle 

up when they went through weigh stations. The general feeling among safety belt users is that if 

the penalty for getting a safety belt ticket were made as strict and as steep as that for getting a 

speeding ticket, people would start wearing safety belts. 

4.2.7. Topic 7: Twelve Technologies to Increase Safety Belt Use 

The 12 technologies considered in this study are presented next, along with representative 

statements or observations from drivers. Other suggestions and comments provided by the 

drivers are presented as well. 

Technology 1. Safety Belt Tension Adjustor 

Most of the drivers had the safety belt tension adjustor (or Komfort Latch) in their trucks. Not all 

of the drivers who had the Komfort Latch used it, although many did. Many drivers felt that the 

Komfort Latch made wearing the safety belt much more comfortable, and in some cases, drivers 

said they would not wear the safety belt without the Komfort Latch. 

There was some confusion about the Komfort Latch’s effectiveness in a crash. Some believed 

that the Komfort Latch Device (plastic clip) was the only structure restraining the driver and that 

it would break during a crash. Some reported using the Komfort Latch to add a lot of slack to the 

safety belt, indicating that they sometimes add so much slack that their upper bodies would hit 

the steering wheel in the case of a crash. Some of these drivers were doing it to get around 

safety-belt-use laws; others did it for personal comfort. 

Some felt that the Komfort Latch would not promote safety belt use. A small number felt that 

putting extra slack in the safety belt presented a hazard and that introduction of the Komfort 

Latch in more vehicles would not serve as an incentive for nonusers to begin using safety belts. 

Others were more positive and felt that if nonusers were instructed in the proper way to use the 

Komfort Latch, they might find them acceptable and feel more comfortable when wearing a 

safety belt. 

The sliding Komfort Latch was not mentioned by the drivers. Many people mentioned the 

padded shoulder safety belt covers that protect a driver’s neck. They said the pads help, but were 

36 
irritating over time. Some drivers indicated that they use a towel between the safety belt and their 

neck or chest for comfort. 

Technology 2. Integrated Safety Belt 

Drivers felt that a seat-integrated safety belt system seemed like a good idea to improve comfort. 

They understood that the shoulder strap upper anchorage point is integrated into the seat and they 

felt that this would be helpful in keeping the safety belt from rubbing against the neck. This was 

thought to be a good solution to the issue of the seat moving up and down, while the shoulder 

strap stays stationary, as in existing truck safety belts. Some drivers had integrated safety belts in 

their personal vehicles and felt that they worked well. One issue that the drivers immediately 

brought up was the concern that the seat would not be strong enough in case of a crash. 

Technology 3. Four-Point Safety Belt 

Four-point safety belts received strongly negative comments from most of the drivers. They were 

seen as potentially restrictive and hard to get out of in case of emergency. They were not seen as 

comfortable; however, none of the drivers had any personal experience with a four-point restraint 

system. In general, both the users and nonusers agree that the four-point safety belt does not 

seem viable. 

Technology 4. Audible Reminders 

The first response to the audible reminder was that drivers would find ways to disable them. 

Some felt that basic audible reminders that chime for a short period and shut off were not a 

strong intervention, but others said they might notice the chime and be reminded to buckle up. 

Regarding the enhanced system that chimes intermittently until drivers do buckle up, many felt 

the system would likely be effective in increasing belt use. Most drivers quickly understood how 

the system would work, since it exists in many passenger vehicles today. They felt that some 

drivers might attempt to disable the system, but many indicated that they would likely buckle up 

simply to stop the noise. They all agreed that it would be aggravating. Several suggested that 

some types of drivers making frequent stops (for deliveries or construction) should not be 

required to wear safety belts, or should not be required to have these systems in their trucks. 

Technology 5. Dash Warning Light 

In the discussion, the dash warning light was not reported by any as an effective way of 

increasing safety belt use. In addition, disabling or covering it up was seen as very easy. New 

large trucks are beginning to be equipped with this technology, although it is not a requirement. 

It is estimated that 30 percent to 50 percent of new Class 8 trucks are equipped with passive dash 

warning light systems (see Table 3 for estimates in other vehicle classes). 

Technology 6. Transmission Interlocks 

Many of the safety belt users felt that the transmission interlock would certainly work, since 

drivers could not move their trucks unless they wore safety belts. However, they were unclear 

how the devices would be implemented. They strongly objected to having a technology that 

could require them to wear safety belts when maneuvering vehicles in parking areas or backing 

37 
up the truck. Another strong concern is that the technology would malfunction, which could 

make them lose a day of work, or be late with a delivery, or leave them stranded. 

Technology 7. Heating and Cooling System Interlocks 

The concern with this idea was primarily that the heating and cooling system should work while 

the vehicle is parked, and that the driver would not be required to wear a safety belt at that time. 

Another concern is that it might break, especially during the cold winter months. 

Technology 8. Entertainment System Interlock 

The radio or CD players were not considered as important as the CB radio. Some said that their 

entertainment system was not important to them. Again, most said that this should not impair 

their ability to use the CB radio when the truck was not moving and when they did not need to 

wear safety belts. This technology did not generate a lot of discussion. 

Technology 9. Onboard Data Recorders 

OBDRs met with a generally negative response from the drivers, particularly from the nonusers 

of safety belts. The potential to circumvent the system was discussed at length. The question of 

who would collect the onboard data for owner-operators was considered. The assumption is that 

DOT would collect it. There was a lot of suspicion that the onboard data collectors would be 

used to collect many other different types of data that would be used against the driver. 

Technology 10. Exterior Safety-Belt-Use Indicator Light 

The new concept of an exterior safety-belt-use indicator light was met with a great deal of 

resistance. Drivers felt that this type of device would be unfair treatment since passenger 

vehicles had no such requirement. They also felt that enforcement officials (primarily police) 

would not want to spend valuable time pulling over drivers in violation of safety belt use laws 

and that they would use the safety-belt-use indicator light to stop vehicles to find other issues to 

cite. Later in the project, someone suggested that the light be affixed to the truck cab, not the 

trailer. The exterior safety-belt-use light was seen as technically challenging and expensive to 

implement because the cab and the load had different electrical systems. 

Technology 11. Brightly Colored Safety Belts 

This was one of the selections most favored by the safety belt users. They felt that the increased 

enforcement brought about through brightly colored safety belts would encourage nonusers to 

wear safety belts. One driver stated that safety belts in all CMVs would need to be changed to a 

bright color at the same time to make law enforcement consistent. 

The nonusers were much less enthusiastic about brightly colored safety belts and suggested ways 

to get around the safety belt. There are already shirts on the market that have a safety belt printed 

across the front, giving the impression that the driver is buckled. Drivers suggested wearing 

shirts the same color as the safety belt. 

38 
Another driver suggested that the safety belts have a heat strip on the back. This would indicate 

to the police office whether it had been on the driver or whether the driver had just buckled up 

upon being pulled over. Another driver suggested that they just spray paint all the safety belts a 

bright color. 

Technology 12. Weigh Station Transponder 

The weigh station transponder is seen as a variation on cameras at the weigh stations, which 

already do the same job. Some envisioned the transponder as working like the prepass. They felt 

that this would be effective since truck drivers would buckle up to be able to use the prepass and 

avoid direct contact with the DOT inspectors. Some thought, however, that the safety belts could 

be removed as soon as they passed through the station. 

4.2.8. CMV Driver Discussion Summary 

The driver discussions highlighted many concerns and opinions regarding the use and 

effectiveness of safety belts and the proposed technologies. They showed a broad range of 

perspectives on most topics, while occasionally showing agreement among safety belt users and 

nonusers. Overall, safety belt users and nonusers favored brightly colored safety belts and safety 

belt tension adjustors. Nonusers felt that enhanced audible reminders would be obtrusive, which 

suggests that they would be effective in compelling drivers to buckle up. Safety belt users 

acknowledged that they would likely not be affected by reminder systems and indicated that this 

would be an acceptable and practical solution. The possible impact of seat-integrated safety 

restraints was not well understood; however, drivers did recognize the potential for reduced 

rubbing and irritation with seat-integrated safety restraints compared to traditional safety belts 

affixed to the vehicle B-pillar. 

During the discussion, drivers suggested that education regarding the effectiveness of safety belts 

and the correct use of technologies would help to dispel common myths about the “dangers” of 

wearing a safety belt. Many agreed that education and the threat of monetary penalties or 

rewards are the best ways to encourage safety belt use. 

39 
5. BENEFIT-COST ANALYSIS 

Below, a benefit cost analysis (BCA) is presented that compares the likely injury and fatality 

reductions due to increased safety belt use with the estimated cost of devices that are designed to 

promote the use of safety belts. Injuries and fatalities for drivers of all large trucks 10,001 

pounds or more GVWR, specifically Class 7 and Class 8 drivers, are considered here. The 

resulting data allow for the evaluation of any safety belt technology option if a device cost is 

known and an estimate of device effectiveness in promoting safety belt use can be made. Within 

Chapter 6, these data are applied to estimate BCRs for the four most promising systems as 

indicated by industry stakeholders. 

This chapter is divided into three sections describing: (1) the data sources and derivation of 

injury costs by safety belt use/non-use for Class 7 and 8 drivers, (2) device costs for technologies 

under consideration, and (3) a matrix of BCRs that can be applied to evaluate any of the devices 

under consideration. 

In general, the analysis presented first involves the determination of injury costs for belted 

drivers and unbelted drivers. Since safety belts are not equally effective for all crash types (headon, rollover, rear, etc.), it was necessary to calculate separate injury costs by safety belt use/nonuse for each crash type. The difference between the actual annual cost of injury to belted and 

unbelted drivers of large trucks and the expected cost of injury if all drivers were now belted is 

the potential injury cost savings. The maximum injury benefit would be realized if a safety belt 

technology was 100 percent effective in increasing safety belt use (e.g., addressing the 41 

percent of drivers not currently buckled). Since a 100 percent usage rate is not likely, the total 

potential cost savings is scaled based on the changes in usage rate anticipated for each device. 

Anticipated increases in safety belt use per device were estimated based on expert opinions 

provided by industry stakeholders. 

For example, if a device compels 20 percent of the unbelted population to buckle up, it is 

expected that 20 percent of the potential injury cost reductions would be achieved. This value is 

then compared to the cost per proposed device, amortized over the anticipated lifespan of the 

device, times the number of vehicles in the fleet to be equipped. If the ratio of the injury benefit 

to the total fleet-wide cost is greater than 1, the device is considered cost-beneficial. Similarly, if 

the total injury benefit anticipated is less than the cost to install the device across the vehicle 

fleet, the device is not cost-beneficial. 

5.1. INJURY COSTS 

In this section, total injury costs for two populations were calculated. The first is the total cost of 

injury based on the current safety belt use rates. The second estimates injury costs if all drivers 

were belted. The difference between these two costs provides an overall estimate of the total 

potential opportunity for cost savings with increased safety belt use. 

Modeling injury costs by safety belt use/non-use requires information regarding the number of 

belted and unbelted occupants involved in crashes, the medical details of each person’s injuries, 

and the costs of those injuries and associated travel delay. The 2001–2003 LTCCS data provide a 

40 
sample of recent United States truck incidence data on crash injuries that record both safety belt 

use and medical descriptions of the injuries. To qualify for the LTCCS sample, a crash must have 

involved a large truck with at least one fatality (“K,” “A,” or “B” injury on the KABCOU scale, 

where K = killed, A = incapacitating injury, B = non-incapacitating injury, C = possible injury, O 

= no injury, and U = injury, severity unknown). The 2001–2003 LTCCS data were used in this 

study to estimate injury costs by safety belt use/non-use for these crashes, and the 1982–1986 

National Automotive Sampling System (NASS) data were used for less severe crashes. However, 

using the LTCCS sample in the analysis for this report introduces selection bias since it is likely 

that some “C” or “O” crashes were left out of the sample because safety belts might have 

prevented injuries that could otherwise be severe enough to qualify for entering the sample. 

To calculate the cost of injuries in the 2001–2003 LTCCS data, costs per victim in 2000 dollars 

were assigned by body part, whether or not a fracture was involved, and Abbreviated Injury 

Scale (AIS) score. These were updated to 2005 dollars and were merged onto the crash files, 

calculating the economic costs per victim. A more detailed description of the process used to 

assign per person costs is provided in Zaloshnja, et al. (2004). The costs per person are also 

applied for other transportation cost evaluations for FMCSA, NHTSA, and the Federal Highway 

Administration (FHWA). Economic costs represent the present value of all injury-related costs 

that result from a crash over the victim’s expected lifespan, computed at a 4 percent discount 

rate. This discount rate was chosen in order to be consistent with NHTSA’s and FHWA’s 

methodology. Included were the following major categories of costs: (1) medically related, (2) 

emergency services, and (3) lost productivity (wage and household work). These items, when 

summed, are the economic cost of injury. Comprehensive costs include items 1–3 plus the 

monetized value of pain, suffering, and lost quality of life. For this study, economic costs were 

used because this cost is most likely absorbed by employers in the event of a crash. 

A number of data sources were used to determine injury costs. Medical cost estimates were 

drawn from 1992–1994 Civilian Health and Medical Program of the Uniformed Services 

(CHAMPUS) data for physician and emergency department fees, 1994–1995 data on hospital 

costs from Maryland and New York (the only two states where costs, not charges or payments, 

were known), and the 1987 National Medical Expenditure Survey (NMES) and 1979–1987 

National Council on Compensation Insurance (NCCI) data on the percentage of costs that occur 

more than six months post-injury. Short-term productivity loss is based on information from the 

NASS Crashworthiness Data System (CDS) 1988–1991 (for AIS 85) and CDS 1993–1999 (for 

AIS 90) to determine the probability that an employed person would not be able to work due to a 

specific injury. Further, the 1993 Survey of Occupational Injury and Illness (SOII) of the U.S. 

Bureau of Labor Statistics was used to estimate the days of work lost per person due to injury. 

Mean probabilities of work loss were estimated from just those CDS records that had the 

relevant information, which frequently was missing. Long-term productivity loss by diagnosis 

was based on 1979–1987 NCCI Detailed Claims Information (DCI) data on the probability that 

injuries would cause permanent partial/total disability and 1997 DCI data on the percentage loss 

of earning power for partially disabled injury victims. 

Various other direct costs were also determined, including emergency services costs, travel 

delay, insurance claims administration, legal and court costs, and workplace disruption costs. 

These estimates used insurance data, recent data on travel delay that crashes caused to motorists 

whose vehicles did not crash, and data from prior NHTSA studies. 

41 
42 

The effect of varied safety belt effectiveness by crash type must be accounted for when 

calculating injury costs. Mean costs were calculated while controlling rollover, rear-end, headon, angle, sideswipe, and other frontal collisions. The analysis of K, A, and B crashes from the 

LTCCS indicated that differences in mean injury costs between belted and unbelted truck drivers 

were statistically significant at the 95 percent confidence level for all crash types, with the 

exception of sideswipe crashes and rear crashes in which the large truck was the vehicle struck. 

This result is logical, since safety belts are most effective in preventing occupant contact with 

interior components and occupant ejections. 

The data shown in Table 5 indicate that if all unbelted drivers of large trucks (GVWR 10,001 

pounds or more) had been belted at the time of their crashes, the annual economic injury costs 

would have been $675 million lower than those observed ($2,253 million [column 6] minus 

$1,578 million [column 7]). Most of these savings would have come from injury cost reduction 

during rollovers ($434 million), followed by injury cost reductions during head-on collisions and 

other frontal collisions ($120 million). 

The data shown in Table 5 indicate that if all Class 7 and 8 truck drivers were belted at the time 

of their crashes, the annual economic injury costs would have been $489 million lower than 

those observed ($1,903 million [column 6] minus $1,414 million [column 7]). Most of these 

savings would have come from injury cost reduction during rollovers ($369 million), followed 

by head-on collisions and other frontal collisions ($134 million). At this time however, it is clear 

that no device exists that is capable of increasing safety belt use to 100 percent. The estimate 

allows for the direct calculation of likely cost reduction if the device effectiveness is known or 

can be estimated. These cost estimates are applied in Chapter 6 to estimate cost-benefit ratios, 

assuming an estimated effectiveness for each of the safety belt technologies considered here. The 

chapter applies estimated effectiveness values in order to estimate injury cost reductions likely 

with the implementation of each device. 
Table 4. Annual Injury Cost Savings If Drivers in All Large Truck Crashes Were Belted 

Crash Type 

Safety 

Belt Use 

Observations 

(LTCCS) 

Annual 

Frequency 

Mean 

Economic 

Injury Cost 

Annual 

Economic 

Injury Cost 

(in 2005 

$ millions) 

Annual 

Economic 

Injury Cost I

All Unbelted 

Drivers Were 

Belted (in 200

$ millions) 

Rollover Unbelted 83 5,479 $145,384 $797 $363 Rollover Belted 125 7,332 $66,125 $485 $485 Rear-end Unbelted 46 1,941 $14,048 $27 $49 Rear-end Belted 210 9,118 $25,308 $231 $231 Head-on Unbelted 9 468 $276,781 $130 $9 Head-on Belted 35 1,770 $19,600 $35 $35 Angle Unbelted 39 1,533 $45,360 $70 $16 Angle Belted 231 10,133 $10,522 $107 $107 Sideswipe Unbelted 12 631 $3,934 $2 $2 Sideswipe Belted 38 2,061 $3,020 $6 $6 Other Unbelted 30 1,173 $148,986 $175 $86 Other Belted 60 2,582 $73,709 $190 $190 Drivers of All Large Trucks Unbelted 219 11,224 $106,919 $1,200 $525 Drivers of All Large Trucks Belted 699 32,996 $31,926 $1,053 $1,053 

Total 918 44,220 $50,961 $2,253 $1,578 

Source: LTCCS 2001–2003 data. Note: Economic injury cost excludes monetized value of pain, suffering, and lost quality of life.

43 
44 

Table 5. Annual Economic Injury Cost Savings If All Class 7 and 8 Truck Drivers in Crashes Were 

Crash Type 

Safety 

Belt Use 

Observations 

(LTCCS) 

Annual 

Frequency 

Mean 

Economic 

Injury Cost 

Annual 

Economic 

Injury Cost 

(in 2005 

$ millions) 

Annual 

Economic 

Injury Cost I

All Unbelted 

Drivers Were 

Belted (in 200

$ millions) 

Rollover Unbelted 73 4,870 $142,450 $694 $325 Rollover Belted 112 6,639 $66,596 $442 $442 Rear-end Unbelted 41 1,802 $14,293 $26 $40 Rear-end Belted 193 8,597 $22,017 $189 $189 Head-on Unbelted 7 374 $149,555 $56 $7 Head-on Belted 33 1,769 $19,431 $34 $34 Angle Unbelted 31 1,154 $10,800 $12 $12 Angle Belted 213 9,543 $10,326 $99 $99 Sideswipe Unbelted 10 590 $4,042 $2 $2 Sideswipe Belted 33 1,880 $2,862 $5 $5 Other Unbelted 28 1,036 $158,802 $165 $80 Other Belted 49 2,314 $77,080 $178 $178 Drivers of All Large Trucks Unbelted 190 9,827 $97,165 $955 $466 Drivers of All Large Trucks Belted 633 30,741 $30,840 $948 $948 

Total 823 40,568 $46,906 $1,903 $1,414 

Source: LTCCS 2001–2003 data. Note: Economic injury cost excludes monetized value of pain, suffering, and lost quality of life
5.2. DEVICE COSTS 

Cost estimates applied during this analysis included both aftermarket device costs and 

installation costs when possible, or original equipment estimated costs. The original equipment 

costs do not account for device development costs, re-engineering of devices, or testing required 

for certifying the systems. This allows for the objective comparison of costs for multiple systems 

without the need to request proprietary development and engineering costs from device suppliers 

and OEMs. 

It should be mentioned that few devices described in Chapter 3 are available as original 

equipment or as aftermarket products. The cost to a buyer to incorporate certain features would 

be drastically lower if the equipment were installed by the manufacturer when the vehicle is first 

assembled. As an example, if a vehicle were equipped with a brightly colored safety belt at the 

manufacturers, the incremental cost of installing the safety belt system, which is only $12 more 

to purchase, is far less significant. This minimal cost increase is likely due to the difference in 

production volumes for black versus brightly colored safety belts. However, if brightly colored 

safety belts are purchased as an aftermarket product, the current standard industry practice is to 

replace the complete safety belt system, including the safety belt webbing, buckle and stalk, Dring, and retractor. This information was provided by certified repair shops and aftermarket 

device manufacturers. Cost estimates for complete system replacements vary by vehicle; 

however, estimates range from $95–$120 for baseline systems with brightly colored webbing. In 

addition, labor costs are approximately $90 for a complete replacement safety belt system. 

Another important factor to consider, which is unique to CMV safety belts, is the replacement of 

subcomponents. Based on information supplied by certified repair shops and restraint 

manufacturers, it is not possible to replace individual components of a safety belt system. 

Because of potentially unsafe incompatibilities between parts, it is not possible to replace the 

safety belt webbing, latch plate, buckle, and buckle stalk, D-ring, or retractor mechanism 

separately. Rather, the replacement of one component requires replacement of the entire system. 

This condition significantly increases the total cost that would be expected to retrofit the entire 

vehicle fleet with upgraded or slightly varied components. 

In Chapter 3, a description of 13 safety belt technologies that could impact safety belt use was 

presented. From that list, four of the most promising systems (enhanced audible reminders, 

brightly colored safety belts, seat-integrated safety restraints, and safety belt tension adjustors) 

were selected based on stakeholder feedback. The process of estimating aftermarket costs for 

these devices was not straightforward. Table 6 lists aftermarket costs plus labor costs, in addition 

to original equipment costs, for some of the technologies. 

45 
Table 6. Estimated Safety Belt Device Costs 

Technology 

Estimated 

Device Plus 

Installation Cost 

Safe Driving Sticker (sticker plus 1 year of service) $15 

Brightly Colored Safety Belt System (aftermarket cost including labor) $197 

Brightly Colored Safety Belt System (original equipment, manufacturer’s cost) $107 

Safety Belt System plus Adjustable D-ring (original equipment, manufacturer’s 

cost) 

$115 

Safety Belt System plus Komfort Latch Device (original equipment, manufacturer’s 

cost) 

$125 

Safety Belt System plus Buckle Sensor and Active Visual Reminder (original 

equipment, manufacturer’s cost) 

$170 

Safety Belt System plus Buckle Sensor Enhanced Audible Reminder (original 

equipment, manufacturer’s cost) 

$170 

Seat-Integrated Safety Restraint System (original equipment, manufacturer’s cost) $700 

Electronic Onboard Data Recorder (basic system: original equipment, 

manufacturer’s cost) 

$2,500 

As mentioned previously, only one configuration is available for a safety belt system for a 

particular make, model, and model year vehicle. For example, it is not possible to order a safety 

belt system with an optional Komfort Latch device or an optional height adjustor. For this 

reason, it was difficult to discriminate the incremental cost for certain components like the 

Komfort Latch and D-ring height adjustors. In order to determine an average price for the 

baseline safety belt system, a system with an adjustable D-ring and a system with a Komfort 

Latch device, the research team identified three vehicles with each configuration and contacted 

parts suppliers to determine replacement costs per device. The costs are listed in Table 6. As 

shown in the table, the per-vehicle cost for the safe driving sticker ($15 including 1 year of 

service by a monitoring company) is the least expensive option considered. Original equipment 

for brightly colored belts (total cost $107 = $95 for basic belt system + $12 for upgraded 

webbing) is the second least expensive device. 

The brightly colored safety belt system and the active visual reminder systems are available as 

optional upgrades from the manufacturer, so that device costs shown are calculated by adding the 

incremental cost increase quoted by manufacturers to the baseline average device cost. 

Since equipping a vehicle with a technology like those shown in Table 6 results in a one-time 

cost increase during vehicle purchase, the cost was evenly distributed, or the cost of the device 

was amortized, over the expected lifetime of the vehicle. This allowed comparison of the annual 

cost of the device with the anticipated annual injury savings. The estimated lifespan of large 

trucks in primary use is 12 years. Many vehicles are kept in service beyond 12 years, but their 

46 
use is infrequent and not considered primary. This amortized device cost is then multiplied by 

the number of vehicles registered in 2005 (FHWA, 2005), resulting in an estimate of the annual 

device cost to equip the full fleet. Based on 2005 data, there were 8,481,999 large trucks 

registered and 2,328,205 of those were Class 7 and 8 vehicles. 

Each device cost is amortized over 12 years (lifespan of the device) at a 4 percent discount. The 

figure of 4 percent was chosen to be consistent with the 4 percent used to discount crash costs. 

5.3 BENEFIT-COST RATIOS 

BCRs are calculated by dividing the annual expected injury benefit in dollars by the annual cost 

of the devices. If the ratio is greater than 1, the device can be thought of as cost-beneficial, or 

providing a positive return on investment. The investment would be the purchase of the safety 

device by an individual or fleet owner, and the return would be a reduction in the cost of injury 

sustained by drivers and likely paid for by fleet owners directly or through insurance or other 

means. 

As an example, Table 7 lists device costs where the anticipated cost of devices equals the 

anticipated savings due to injury reduction. These costs are the maximum amount that could be 

spent on a device before a negative return on an investment in a safety device would occur. With 

regard to Table 7, even if only a 5 percent increase in safety belt use were realized through the 

addition of a particular device, it would prove to be cost-beneficial if it costs less than $91 for all 

trucks and less than $240 for Class 7 and 8 trucks. Similarly, if a device increases safety belt use 

by 30 percent, any device costing less than $545 for all trucks and $1,440 for Class 7 and 8 

trucks would prove to be cost-beneficial when fatality and injury reductions are considered. 

Table 7. Maximum Device Cost versus Anticipated Effectiveness 

Anticipated 

Increase in Safety 

Belt Use 

Maximum Cost 

Effectiveness per Vehicle 

for All Large Trucks 

Maximum Cost 

Effectiveness per Vehicle 

for Class 7 and 8 Vehicles 

5% $91 $240 

10% $182 $480 

15% $273 $725 

20% $364 $960 

25% $454 $1,200 

30% $545 $1,440 

35% $635 $1,680 

40% $730 $1,920 

1A device that is expected to increase safety belt use by 5 percent would improve wearing rates 

from 59 percent (2006 estimate) to 64 percent if fully deployed. 

In order to determine an exact BCR, exact device costs and exact effectiveness values are 

required. In this case, neither value is known with certainty for the most promising safety belt 

technologies described previously. For this reason, Table 8 provides a matrix of BCRs for the 

population of drivers of all large trucks. (Table 9 provides similar information for Class 7 and 8 

drivers only.) Each cell represents the ratio of a single device cost at a given effectiveness. As an 

47 
example, if a device that leads to a 10 percent increase in overall safety belt use by Class 7 and 8 

drivers is purchased at a price of $80, the BCR value of 4 indicates that for every dollar spent to 

purchase and equip trucks with the device, a $4 return is expected for companies. Similarly, if $1 

million is spent, a $4 million return in injury cost savings is anticipated. 

The matrix of BCRs shown in Tables 8 and 9 is presented so that the BCRs for other devices not 

explicitly discussed in this document can be determined. 

Table 8. Generalized Benefit-Cost Ratios for Safety Belt Technologies for Drivers of All Large 

Trucks—Anticipated Increase in Safety Belt Use (from 59% baseline) 

Device Cost 5% 10% 15% 20% 25% 30% 35% 40% 

$10 9.11 18.22 27.33 36.43 45.54 54.65 63.76 72.87 

$20 4.55 9.11 13.66 18.22 22.77 27.33 31.88 36.43 

$30 3.04 6.07 9.11 12.14 15.18 18.22 21.25 24.29 

$40 2.28 4.55 6.83 9.11 11.39 13.66 15.94 18.22 

$50 1.82 3.64 5.47 7.29 9.11 10.93 12.75 14.57 

$60 1.52 3.04 4.55 6.07 7.59 9.11 10.63 12.14 

$70 1.30 2.60 3.90 5.20 6.51 7.81 9.11 10.41 

$80 1.14 2.28 3.42 4.55 5.69 6.83 7.97 9.11 

$90 1.01 2.02 3.04 4.05 5.06 6.07 7.08 8.10 

$100 0.91 1.82 2.73 3.64 4.55 5.47 6.38 7.29 

$200 0.46 0.91 1.37 1.82 2.28 2.73 3.19 3.64 

$300 0.30 0.61 0.91 1.21 1.52 1.82 2.13 2.43 

$400 0.23 0.46 0.68 0.91 1.14 1.37 1.59 1.82 

$500 0.18 0.36 0.55 0.73 0.91 1.09 1.28 1.46 

$600 0.15 0.30 0.46 0.61 0.76 0.91 1.06 1.21 

$700 0.13 0.26 0.39 0.52 0.65 0.78 0.91 1.04 

$800 0.11 0.23 0.34 0.46 0.57 0.68 0.80 0.91 

$900 0.10 0.20 0.30 0.40 0.51 0.61 0.71 0.81 

$1,000 0.09 0.18 0.27 0.36 0.46 0.55 0.64 0.73 

$2,000 0.05 0.09 0.14 0.18 0.23 0.27 0.32 0.36 

$3,000 0.03 0.06 0.09 0.12 0.15 0.18 0.21 0.24 

48 
Table 9. Generalized Benefit-Cost Ratios for Safety Belt Technologies for Class 7 and 8 Drivers—

Anticipated Increase in Safety Belt Use (from 59% baseline) 

Device Cost 5% 10% 15% 20% 25% 30% 35% 40% 

$10 24.09 48.18 72.27 96.36 120.45 144.54 168.63 192.72 

$20 12.05 24.09 36.14 48.18 60.23 72.27 84.32 96.36 

$30 8.03 16.06 24.09 32.12 40.15 48.18 56.21 64.24 

$40 6.02 12.05 18.07 24.09 30.11 36.14 42.16 48.18 

$50 4.82 9.64 14.45 19.27 24.09 28.91 33.73 38.54 

$60 4.02 8.03 12.05 16.06 20.08 24.09 28.11 32.12 

$70 3.44 6.88 10.32 13.77 17.21 20.65 24.09 27.53 

$80 3.01 6.02 9.03 12.05 15.06 18.07 21.08 24.09 

$90 2.68 5.35 8.03 10.71 13.38 16.06 18.74 21.41 

$100 2.41 4.82 7.23 9.64 12.05 14.45 16.86 19.27 

$200 1.20 2.41 3.61 4.82 6.02 7.23 8.43 9.64 

$300 0.80 1.61 2.41 3.21 4.02 4.82 5.62 6.42 

$400 0.60 1.20 1.81 2.41 3.01 3.61 4.22 4.82 

$500 0.48 0.96 1.45 1.93 2.41 2.89 3.37 3.85 

$600 0.40 0.80 1.20 1.61 2.01 2.41 2.81 3.21 

$700 0.34 0.69 1.03 1.38 1.72 2.06 2.41 2.75 

$800 0.30 0.60 0.90 1.20 1.51 1.81 2.11 2.41 

$900 0.27 0.54 0.80 1.07 1.34 1.61 1.87 2.14 

$1,000 0.24 0.48 0.72 0.96 1.20 1.45 1.69 1.93 

$2,000 0.09 0.19 0.28 0.37 0.47 0.56 0.65 0.75 

$3,000 0.06 0.12 0.19 0.25 0.31 0.37 0.43 0.50 

49 
CHAPTER 6. TECHNOLOGY SUMMARY 

In this chapter, a synthesis is presented of all available information regarding the four safety belt 

technology strategies considered the most promising. The method used to select the most 

promising systems included both subjective and objective criteria. The decision was based on the 

feedback of industry stakeholders regarding the most reasonable, potentially effective, and costeffective systems. In addition, user acceptability was obtained through driver discussions and 

resulting feedback. The following four technologies were selected as the most promising: 

• Enhanced Audible Reminders 

• Brightly Colored Safety Belts 

• Safety Belt Tension Adjustors 

• Seat-Integrated Safety Restraints 

Data gathered during the literature review, industry stakeholder discussions, and driver 

discussions are presented in the following sections. Final BCRs are presented for the population 

of all large trucks by device and also for the population of Class 7 and 8 trucks per device. Based 

on 2005 data reported by FHWA, there were 8,481,999 large trucks registered (GVWR 10,001 

pounds or more) and 2,328,205 of these were Class 7 and 8 vehicles. Device effectiveness in 

increasing safety belt use is estimated based on expert opinions provided by industry 

stakeholders. These effectiveness values are estimates and were necessary for the purpose of 

calculating BCRs; however, observational studies of actual changes in belt use with the 

implementation of each device should be conducted to confirm these values. 

The methodology used to estimate BCRs was presented in Chapter 5. The matrix of values listed 

in Tables 8 and 9 allows the reader to determine the BCR for any promising system likely to 

increase driver belt use, if the device cost and potential effectiveness of each system are known. 

6.1. ENHANCED AUDIBLE REMINDERS 

The enhanced audible reminder system seemed to appeal most to stakeholders. This device, 

available as a standard feature in over 75 percent of new passenger vehicles sold in 2006, 

provides a repeating audible alert to drivers until safety belts are properly engaged (Alliance of 

Automobile Manufacturers, 2006). One implementation of this system in passenger cars provides 

an 8-second alert every 20 seconds for up to 5 minutes until safety belts are fastened (Williams, 

2003). After a period of 5 minutes, these systems stop issuing the audible reminder. Other 

implementation strategies have also been used in which the intensity of the audible chime, 

frequency of alerts, time duration, and the alert’s sound are varied (Saab, 2005). Within the 

scientific literature, little information is available describing specific implementation strategies 

for large trucks. Useful guidelines do exist for passenger car drivers that could aid in the 

development of future systems if enhanced audible reminders were considered for 

implementation in large trucks (Eby, et al., 2005). 

The Transportation Research Board (TRB) Special Report 278 study (Howell, et al., 2003) 

considered technologies to increase safety belt use in passenger vehicles and concluded that 

50 
enhanced audible reminders would be effective in increasing safety belt use rates while not being 

overly obtrusive. The European vehicle rating system (EuroNCAP) assigns bonus points when 

rating vehicles if an enhanced audible reminder system is present. 

6.1.1. Stakeholder Perspectives 

The enhanced audible reminder was the device most widely accepted and supported by vehicle 

OEMs, government personnel, and industry trade organizations. Numerous stakeholders 

supported this technology, indicating that the approach has been widely successful for passenger 

vehicles and would likely be successful for large-truck applications as well. The manufacturers 

indicated that the components necessary to implement an enhanced audible reminder system are 

readily available and would require minimal engineering effort to implement as an original 

equipment strategy. Stakeholders warned that care must be taken to properly integrate systems 

into the large-truck environment, which differs in many ways from the passenger vehicle fleet. 

For example, devices should account for the fact that drivers may need to be unbelted to perform 

low-speed driving tasks while parking or during other work-related activities. 

Drivers felt that the device would be effective. A small number of nonusers indicated that the 

device would be sufficiently annoying that they would attempt to disable the system. Many parttime drivers felt that they would benefit from the reminder, and they would appreciate being able 

to temporarily or permanently disable the system if needed. The population of safety belt users 

identified that the chime would have little impact on them. They anticipated that they would 

never hear the reminder because they typically operate their vehicles only when their safety belts 

are fastened. All drivers (users and nonusers) felt that the devices would increase safety belt use 

by drivers in their industry. 

6.1.2. Anticipated Device Effectiveness 

Effectiveness data for enhanced audible reminder systems exist for passenger vehicle 

applications only. The data are based on direct observation of passenger-vehicle-driver safety 

belt use and were reported by Williams, et al. (2003). The study reports that a 7 percent higher 

safety belt use rate was observed for passenger vehicle drivers whose vehicles were equipped 

with the system, compared to drivers of vehicles not equipped with the technology. This 

incremental difference provides one estimate of the potential effectiveness of an audible 

reminder system in large trucks. However, the Ford system allows users to temporarily or 

permanently disable the device. Without this option, stakeholders anticipate that an enhanced 

audible reminder system would increase safety belt use by CMV drivers by 15 percent. In the 

absence of all other data regarding potential device effectiveness, these data were applied to 

calculate the BCR ratios shown next. 

1. Estimated aftermarket cost: Enhanced audible reminders are not available as aftermarket 

systems. 

2. Estimated original equipment cost: $105 

$70—Buckle with safety belt use sensor switches plus wiring to onboard computer 

$35—Enhancement for onboard computer and interface with existing chime 

51 
3. Anticipated BCR: N/A—Aftermarket 

2.6—Original equipment for all large trucks 

6.9—Original equipment for Class 7 and 8 trucks 

As previously mentioned, a BCR above 1 indicates a positive return on an investment where 

each dollar spent would likely result in more dollars saved by prevention of injuries and fatalities 

than the devices cost. Conversely, a BCR below 1 indicates that the device is not cost-beneficial 

and there would be a negative return on investment. 

6.2. BRIGHTLY COLORED SAFETY BELTS 

Brightly colored safety belt systems are an enforcement strategy in which the bright colors 

permit company officials, DOT inspectors, and law enforcement personnel to more easily 

identify if safety belts are being worn. In addition, the bright color (usually orange or yellow) 

makes safety belt systems more noticeable to drivers and this, too, might serve as a reminder to 

buckle up. This strategy is currently being introduced by fleets of all sizes in order to facilitate 

enforcement of safety-belt-use policies and to encourage drivers to buckle up. Few technical data 

exist regarding this particular device; however, multiple studies have suggested that enforcement 

and the perceived threat of enforcement lead to significant increases in safety belt use. 

6.2.1. Stakeholder Perspectives 

Stakeholders identified brightly colored safety belts as the second most favored strategy for 

increasing safety belt use. Trade organization representatives and insurance personnel identified 

that the introduction of these safety belts to a vehicle indicates to drivers that a company cares 

about the well-being of its drivers. They also felt that introducing the safety belts to fleet vehicles 

provides an opportunity for a company to revisit the issue of safety belt use and provide 

additional safety education to drivers. Devices are cost-effective, especially when included in the 

purchase of a new vehicle. Two fleet safety managers who have already implemented brightly 

colored safety belts in their fleets indicated that these devices have made noticeable differences 

in their drivers’ behavior. Some have suggested that the success of brightly colored safety belts 

relies on the fact that someone is looking for the safety belts (either police or company 

personnel); however, it appeared to fleet managers that the fear of enforcement by police was 

sufficient to increase safety belt use rates. 

6.2.2. Anticipated Device Effectiveness 

Few data are currently available to assess the likely impact of brightly colored safety belts. The 

calculation below assumes an estimated safety belt use increase of 10 percent with the 

implementation of brightly colored belts. This estimate is based on stakeholder feedback and 

researcher opinion regarding the likely effectiveness of this system. Additional studies are 

necessary to determine actual effectiveness values based on observed belt use in the field.

52 
1. Estimated aftermarket cost: $197 

$95—Baseline belt system cost 

$90—Labor 

$12—Incremental cost for changed webbing (due to lower production volumes) 

2. Total estimated original equipment system cost: $107 

$95—Baseline belt system cost 

$12—Incremental cost for changed webbing (due to lower production volumes) 

3. Anticipated BCR 

0.92—Aftermarket for all large trucks 

2.45—Aftermarket for Class 7 and 8 trucks 

1.70—Original equipment for all large trucks 

4.50—Original equipment for Class 7 and 8 trucks 

6.3. SAFETY BELT TENSION ADJUSTORS 

Safety belt tension adjustors are devices that allow users to introduce slack into safety belts to 

improve the overall comfort of safety belts in trucks. Since large trucks often have suspended 

seats that travel vertically and horizontally while the truck is in motion, the relative movement 

between safety belt systems fixed to vehicle interiors and drivers using suspended seats may lead 

to excessive rubbing and irritation of the shoulder and chest of drivers. Currently, safety belt 

tension adjustors (sold commercially as Komfort Latch) are sold in nearly 90 percent of new 

Class 8 vehicles. This estimate was provided by the manufacturer of the Komfort Latch System. 

The device is an integrated component that attaches to the vehicle structure at the D-ring. The 

device can be cinched to hold the safety belt in place after introducing slack into the safety belt 

system. In making the shoulder portion of the safety belt fit less tightly, the rubbing of the safety 

belt across the neck of an occupant is minimized. The system can be disengaged by yanking on 

the system; it will disengage automatically during a collision event, once extended beyond the 

locked level. The system does not affect the activation of web-lockers or load limiters that are 

part of the safety belt system. 

Some questions have been raised regarding the introduction of additional slack into the safety 

belt system. A study by Siegmund, et al. identified a 26 percent to 37 percent increase in head, 

thoracic, and pelvic accelerations and a 20 percent to 54 percent increase in neck loads and 

moments with the addition of 10 centimeters of slack. As reported during manufacturer 

discussions, most commercial vehicles do not come equipped with pretensioning retractors that 

rapidly remove slack from a safety belt system in the event of a crash. This is especially true for 

Class 6 and larger vehicles. Ideally, a safety belt system should closely couple an occupant to the 

decelerating vehicle structure as early as possible during a crash event. If additional slack exists 

53 
in the system, the safety belt does not decelerate an occupant for as long a period of time before 

the vehicle structure comes to rest. In this case, an occupant will experience a higher deceleration 

force over a shorter period of time before he or she is brought from precrash speeds to rest during 

a crash. Additional quantification of the safety effects of added slack would be useful in 

supporting this device. 

6.3.1. Stakeholder Perspectives 

Multiple manufacturers indicated that some vehicles lines are equipped with the safety belt 

tension adjustor (i.e., Komfort Latch System). Although OEMs felt that adding slack to a safety 

belt was not ideal and could lead to reduced safety belt effectiveness in preventing injuries in 

some cases, if this comfort strategy increased safety belt use, some stakeholders suggested the 

tradeoff might be acceptable. A number of drivers reported that they used the safety belt tension 

adjustor regularly and would be less likely to buckle up if their vehicles were not equipped with 

the device. Other drivers indicated that they preferred the baseline safety belt system and did not 

find comfort to be an issue. 

6.3.2. Anticipated Device Effectiveness 

Safety belt tension adjustors are available today in a large proportion of Class 7 and Class 8 

vehicles. In some cases, regular safety belt users prefer not to add any slack to their safety belts 

while driving, even if a Komfort Latch is present. However, it appears there were other cases of 

vehicles being equipped with a Komfort Latch, but it was not used because its function was not 

well understood. This opinion is based on driver discussions. 

Overall, the Komfort Latch could be useful in helping drivers to optimize the comfort of the 

safety belt when they choose to wear it. However, additional education regarding the benefit of 

wearing safety belts and ways to optimize a good fit with a Komfort Latch is essential. For the 

purpose of this evaluation, they were estimated to increase safety belt use by 5 percent.

1. Estimated aftermarket cost: This device is not available as an aftermarket system. 

2. Total estimated original equipment system cost: $125 

$95—Baseline safety belt system cost 

$30—Incremental cost for Komfort Latch device 

3. Anticipated BCR 

N/A—Aftermarket 

0.73—Original equipment for all trucks 

1.93—Original equipment for Class 7 and 8 trucks 

6.4. SEAT-INTEGRATED SAFETY RESTRAINTS 

Seat-integrated safety restraints are a technology that could improve the comfort of safety belts 

without introducing slack into the system. These devices would be mounted directly to air- or 

spring-suspended seats. This eliminates the relative motion between the driver and the safety belt 

54 
system. The safety belts are typically attached to fixed parts of the vehicle interior. This 

difference could address some driver comfort issues. However, attaching the safety belt system 

to the seat structure would increase the load transferred to the seat and mounting structure in the 

event of a crash. Currently, vehicles are not designed to withstand increased load on the seat. 

European designers are introducing seat-integrated safety restraints into their new vehicles. A 

number of studies conducted by European and Australian researchers have identified that seatintegrated safety restraints are a more comfortable alternative to traditional safety belts. 

A seat-integrated safety belt system may also provide improved occupant protection during a 

crash. Since anchorage points (upper anchorage and lower attachment point) for the seatintegrated restraint system are closer to the driver, the degree of upper body restraint provided by 

the system during a crash may be significantly lower than that provided by a traditional system. 

This condition is primarily due to the larger distance between the driver seat and the vehicle Bpillar, and also due to the highly adjustable seats typically found in Class 7 and 8 vehicles. These 

closer attachment points lead to better coupling of the occupant to the seat in the event of a crash. 

Seat-integrated safety belts are not widely available in the United States; however, the 

technology shows much promise. These systems are more commonly available in Europe, 

Australia, and Japan. 

6.4.1. Stakeholder Perspectives 

Vehicle manufacturers (including vehicle structural engineers) indicated that design changes 

would be necessary for some vehicles to include seat-integrated safety restraints; however, 

engineering changes are not prohibitive. One aftermarket device manufacturer conducted 

preliminary evaluations of seat-integrated safety restraints and suggested that the upper 

anchorage location must be variable and further optimized before an acceptable solution can be 

implemented. A 10-percent increase in safety belt use is anticipated with the implementation of 

this device. 

1. Estimated aftermarket cost: $970

Vehicle re-engineering not included here. 

$700—Seat cost 

$270—Labor 

2. Total estimated original equipment system cost: $700 

$700: Seat cost

3. Anticipated BCR 

0.19—Aftermarket cost for all trucks 

0.50—Aftermarket cost for Class 7 and 8 trucks 

0.26—Original equipment for all trucks 

0.69—Original equipment for Class 7 and 8 trucks 

55 
CHAPTER 7. CRASH DATA ANALYSIS

This chapter presents the results of an exploratory analysis of real-world data for fatal and 

nonfatal crashes involving large trucks. Data sources used for this analysis include the FARS 

database for fatal crashes and the Large Truck Crash Causation Study (LTCCS) to investigate 

truck crash causes and driver injury mechanisms in detail. 

Analyses are designed to answer a number of questions and are organized in four sections: 

1. What are the characteristics of fatal crashes involving large trucks, and are there any 

unique characteristics of fatal crashes common to unbelted drivers? 

2. Under what conditions are belted drivers fatally injured? 

3. What percentage of fatally and/or seriously injured unbelted drivers would have had 

improved outcomes if they had been wearing safety belts during their crashes? 

4. What are the general characteristics and primary causes of large-truck rollover crashes? 

To highlight unique characteristics of unbelted drivers, each result presented includes the 

population of belted drivers for comparison. Data are partitioned by truck type and presented 

separately for drivers of trucks whose GVWR is 10,001 pounds or more (referred to here as “All 

Large Trucks”) and for the population of Class 7 and 8 truck drivers (referred to here as “Class 7 

and 8”). Within the data presented in this chapter, the population of Class 7 and 8 drivers is a 

subset of the total population of drivers of large trucks with a GVWR of 10,001 pounds or more. 

7.1. CHARACTERISTICS OF FATALLY INJURED UNBELTED CMV DRIVERS 

The FARS data were used to explore characteristics of large-truck driver-fatal crashes. The 

FARS is a census of police-reported fatal crashes occurring on public roadways in the United 

States where a death occurs within 30 days of the crash. The dataset includes environmental-, 

vehicle-, and occupant-level information for crashes involving large trucks, passenger vehicles, 

motorcycles, and pedestrians. All data elements are derived from police reports, hospital records, 

medical examiner/autopsy reports, and driver licensing information. All information presented is 

reported for the most recent available data year (2005), and in some cases, data from earlier years 

(1995–2005) are shown for comparison. 

Overall, the FARS indicated that 5,212 people died in 2005 during crashes involving large trucks 

(those with a GVWR of 10,001 pounds or more). Of those fatalities, 688 were drivers of the 

large truck and 114 were large-truck passengers. For the subset of vehicles including Class 7 and 

8 trucks, 602 drivers and 100 large-truck passengers died during 2005 calendar year crashes. The 

first goal of this analysis is to describe the characteristics of fatally injured unbelted drivers. 

Table 10 shows the number of belted and unbelted drivers of all large trucks who died during 

crashes occurring from 1995 to 2005. In addition, the table shows the population of fatally 

injured drivers whose safety belt use status could not be accurately determined after the crash. 

For the population of drivers fatally injured in 2005, some 337 were unbelted, which was 49 

percent of the total fatally injured population. This percentage included drivers whose safety belt 

use status was unknown. It is likely that more than half of the driver fatalities where safety belt 

status was unknown were unbelted. Considering only fatalities in 2005 where safety belt use 

56 
status was known for drivers of all large trucks (337 unbelted and 233 belted), 59 percent were 

unbelted, as shown in Table 10. 

Table 10. Fatalities for Belted and Unbelted Drivers of All Large Trucks 

Crash 

Year 

Unbelted 

(% With Belt Use 

Known) 

Belted 

(% With Belt Use 

Known) 

Belt Use 

Unknown 

Total All 

Large 

Trucks 

1995 331 (74%) 116 (26%) 102 549 

1996 324 (74%) 115 (26%) 94 533 

1997 363 (72%) 141 (28%) 113 617 

1998 329 (68%) 153 (32%) 141 623 

1999 338 (66%) 175 (34%) 126 639 

2000 366 (70%) 156 (30%) 123 645 

2001 316 (68%) 152 (32%) 124 592 

2002 302 (66%) 157 (34%) 120 579 

2003 302 (61%) 196 (39%) 107 605 

2004 299 (57%) 224 (43%) 102 625 

2005 337 (59%) 233 (41%) 118 688 

 Source: FARS 1995–2005 data. 

Table 11. Fatalities for Belted and Unbelted Drivers of Class 7 and 8 Trucks 

Crash 

Year 

Unbelted 

(% With Belt Use 

Known) 

Belted 

(% With Belt Use 

Known) 

Belt Use 

Unknown 

Total 

Class 7 

and 8 

1995 285 (73%) 103 (27%) 96 484 

1996 274 (71%) 110 (29%) 86 470 

1997 299 (70%) 127 (30%) 104 530 

1998 286 (69%) 130 (31%) 133 549 

1999 302 (66%) 154 (34%) 116 572 

2000 320 (69%) 143 (31%) 110 573 

2001 278 (67%) 134 (33%) 118 530 

2002 265 (66%) 137 (34%) 113 515 

2003 269 (60%) 177 (40%) 104 550 

2004 267 (57%) 201 (43%) 92 560 

2005 281 (58%) 205 (42%) 116 602 

 Source: FARS 1995–2005 data. 

57 
Table 11 shows the fatality counts by crash year for belted and unbelted drivers of Class 7 and 8 

trucks from 1995–2005. In 2005, some 281 out of 602 driver fatalities, or 47 percent, were 

unbelted. Considering only fatally injured drivers whose safety belt use status was known for 

drivers of Class 7 and 8 trucks (281 unbelted and 205 belted), 58 percent were unbelted in 2005, 

as shown in Table 11. It should be noted that the majority of the drivers of large trucks who died 

during the 1995–2005 crash years were drivers of Class 7 and 8 trucks (i.e.., 602 were Class 7 

and Class 8 drivers versus 688 for all large trucks). 

7.1.1. Crash Type Characteristics 

Tables 12 and 13 show the distribution of driver fatalities by crash type (i.e., rollovers, vehicleto-vehicle collisions, collisions with fixed and nonfixed objects, and noncollisions) in 2005 for 

all large-truck crashes and Class 7 and 8 truck crashes, respectively. These data are based on the 

most harmful event coded by FARS researchers. FARS defines the most harmful event as the 

event during a crash for a particular vehicle that is judged to have produced the greatest personal 

injury or property damage. 

As shown in Table12, rollovers are the most common crash type in which a large-truck driver 

fatality occurs. Of the 688 fatalities, 232 (or 34 percent) of driver deaths occur during rollovers. 

Of these deaths, 66 percent involve an unbelted driver and 34 percent involve a belted driver. 

Vehicle-to-vehicle collisions include all crashes involving another moving vehicle. Of the 133 

large-truck driver deaths occurring during vehicle-to-vehicle collisions, 46 percent involve 

unbelted occupants. 

Collisions with fixed objects include narrow object crashes (impacts with trees and poles); 

crashes with walls, fences, and buildings; and crashes with fixed objects at the roadside, such as 

impact attenuators and guardrails. As shown in Table 12, some 63 percent of the 123 drivers 

fatally injured during collisions with fixed objects were unbelted. The “noncollision” category 

most commonly includes events in which a fire or explosion, a truck jackknife, or an occupant 

ejection without impact occurs. During these events, 48 percent of the fatally injured drivers 

were unbelted. The “collision with a nonfixed object” category includes impacts with parked 

vehicles, trains, and pedestrians/cyclists. Of the occupants involved in these crashes, 71 percent 

were unbelted. 

58 
Table 12. Distribution of Harmful Event Categories 

for CMV Driver Fatalities for All Large Trucks 

Most Harmful Event 

Safety 

Belt Use 

Fatally 

Injured 

Drivers 

Safety Belt Use 

per Event, 

When Known (%) 

CMV Fatalities for All 

Large Trucks, 

Including Unknown 

(%) 

Rollover (250) Unbelted 152 66 36 

Rollover (250) Belted 80 34 

Rollover (250) Unknown 18 

Vehicle-to-Vehicle (163) Unbelted 61 46 24 

Vehicle-to-Vehicle (163) Belted 72 54 

Vehicle-to-Vehicle (163) Unknown 30 

Collision with Fixed Object (139) Unbelted 78 63 20 

Collision with Fixed Object (139) Belted 45 37 

Collision with Fixed Object (139) Unknown 16 

Noncollision (99) Unbelted 26 48 14 

Noncollision (99) Belted 28 52 

Noncollision (99) Unknown 45 

Collision with Nonfixed Object 

(37) 

Unbelted 20 71 5 

Collision with Nonfixed Object 

(37) 

Belted 8 29 

Collision with Nonfixed Object 

(37) 

Unknown 9 

Total 688 100 

Source: FARS 2005 data. 

As suggested by Simon, et al. (2001), wearing a safety belt does not protect all occupants during 

all crashes. In crashes where a large amount of structural intrusion occurs, use of the safety belt 

system may not necessarily prevent serious injuries. However, in the absence of structural 

intrusion, the risk of fatal injury is quite low for properly restrained drivers. As shown in Table 

12 and Table 13, safety belt use has a significant effect on the rate of fatality during rollovers and 

during collisions with fixed and nonfixed objects. Considering rollover crashes as an example, 

the percent of unbelted drivers who died is higher than the belted group (i.e., 66 percent unbelted 

versus 34 percent belted for large trucks), as shown in Table 12. This reflects the fact that many 

rollovers involving large trucks are not high-speed/multiple-roll events. In general, most largetruck rollovers involve only one quarter–turn, where the vehicle rolls only 90 degrees about its 

longitudinal axis. During these lower-severity rollover events, the vehicle structure and occupant 

compartment typically remain intact. During these events, it is possible that fatal injuries occur 

due to partial or full driver ejection, or due to movement of the driver within the vehicle 

compartment during the crash event. This outcome is further supported in section 7.2, 

“Characteristics of Fatally Injured and Belted CMV Drivers,” in which crash characteristics of 

59 
belted drivers who were fatally injured are analyzed. This section highlights the fact that belted 

drivers are more often fatally injured in crashes where major structural damage results. 

Table 13. Distribution of Harmful Event Categories 

for CMV Driver Fatalities in Class 7 and 8 Trucks 

Most Harmful Event 

Safety 

Belt Use 

Fatally 

Injured 

Drivers 

Safety Belt Use 

per Event, 

When Known (%) 

CMV Fatalities for All 

Class 7 and 8, 

Including Unknown (%)

Rollover (223) Unbelted 131 64 37 

Rollover (223) Belted 74 36 

Rollover (223) Unknown 18 

Vehicle-to-Vehicle (132) Unbelted 45 43 22 

Vehicle Belted 59 57 

Vehicle Unknown 28 

Collision with Fixed Object (119) Unbelted 65 63 20 

Collision with Fixed Object (119) Belted 38 37 

Collision with Fixed Object (119) Unknown 16 

Noncollision (93) Unbelted 22 46 15 

Noncollision (93) Belted 26 54 

Noncollision (93) Unknown 45 

Collision with Nonfixed Object (35) Unbelted 18 69 6 

Collision with Nonfixed Object (35) Belted 8 31 

Collision with Nonfixed Object (35) Unknown 9 

Total 602 100 

Source: FARS 2005 data. 

In order to provide further insight into the rate of fatality for the crash events shown in Tables 12 

and 13, Tables 14 and 15 present the number of nonfatal crashes that occur within each category. 

The ratio of fatalities to nonfatal crash involvement provides an indication of the relative severity 

of each crash condition. The crash-involved driver and injured driver counts shown in the tables 

are based on data from the NASS General Estimates System (GES). The NASS GES is a 

population-based sample of police-reported crashes occurring across the United States. Each 

year, approximately 55,000 raw cases are sampled from 60 primary sampling units selected to 

represent the national crash experience. The case data include information collected by police as 

observed on-the-scene and information reported by crash-involved occupants. No further crash 

investigation or reconstruction is conducted beyond collection of police-reported information. 

The NASS GES sampling criteria include crash events of lower severity, including propertydamage-only crashes, and minor, moderate, and severe injury crashes. The data are sampled and 

weighted such that the cases represent all police-reported crashes occurring on public roadways 

involving all vehicles types (including passenger vehicles as well as large trucks and buses). 

60 
Table 14 and Table 15 show that the majority of crash-involved vehicles found in NASS GES 

are vehicle-to-vehicle crashes (75 percent for drivers of all large trucks and for drivers of Class 7 

and 8 trucks), yet rollovers claim the highest percentage of fatalities. Tables 14 and 15 are 

derived from GES and FARS data and include a breakdown of events in which all large trucks 

and Class 7 and 8 vehicles are involved. These events include rollovers, vehicle-to-vehicle 

collisions, fixed-object collisions, noncollisions, and collisions with nonfixed objects. These 

tables do not include a breakdown of safety-belt-use information, due to the inherent 

inaccuracies associated with police-reported safety-belt-use data in NASS GES. As shown in 

column 4 of Table 14, it is clear that rollovers result in the highest number of fatalities per crash 

involvement—2.89 percent of the rollover crashes involving all large trucks resulted in a fatality. 

This is considerably higher than the 0.28 percent fatality rate for all crashes involving all large 

trucks, as shown in the bottom row of Table 14. 

Table 14. Distribution of Harmful Event Categories 

for Drivers of All Large Trucks, Both Unbelted and Belted 

Most Harmful Event 

CrashInvolved 

Drivers, 

number (%) 

Injured 

Drivers, 

number (%) 

Fatally Injured 

Drivers, 

number (%) 

Fatalities per 

Crash-Involved 

Driver (%) 

Rollover 8,649 (4%) 4,432 (37%) 250 (36%) 2.89 

Vehicle-to-Vehicle 180,212 (75%) 5,387 (45%) 163 (24%) 0.09 

Collision with Fixed Object 20,292 (8%) 1,328(11%) 139 (20%) 0.68 

Noncollision (e.g., jackknife, fire) 14,329 (6%) 486 (4%) 99 (14%) 0.69 

Collision with Nonfixed Object 17,044 (7%) 314 (3) 37 (5%) 0.22 

Total 240,526 11,947 688 0.28 (avg.) 

Source: GES 2005 and FARS 2005 data. 

For Class 7 and 8 trucks (see Table 15), a similar rate of fatality is found. Rollovers result in the 

highest number of fatalities per crash involvement; 2.70 percent of the rollover crashes involving 

Class 7 and 8 vehicle trucks result in a fatality, compared to the overall average of 0.30 percent 

for all crashes combined. Based on Table 15, it is also clear that vehicle-to-vehicle crashes result 

in the fewest number of fatalities in the truck per crash involvement. This reflects the fact that 

the majority of vehicle-to-vehicle collisions involved a large truck coming in contact with a 

passenger vehicle. 

61 
Table 15. Distribution of Harmful Event Categories for Drivers of 

Class 7 and 8 Trucks, Both Unbelted and Belted 

Most Harmful Event 

CrashInvolved 

Drivers, 

number (%) 

Injured 

Drivers, 

number (%) 

Fatally Injured 

Drivers, 

number (%) 

Percent of 

Crashes 

Involving a 

Fatality (%) 

Rollover 8,251 (4%) 4,230 (39%) 223 (37%) 2.70 

Vehicle-to-Vehicle 147,123 (75%) 4,699 (43%) 132 (22%) 0.09 

Collision with Fixed Object 18,172 (9%) 1,095 (10%) 119 (20%) 0.65 

Noncollision (e.g., jackknife, fire) 11,919 (6%) 486 (4%) 93 (15%) 0.78 

Collision with Nonfixed Object 11,087 (6%) 314 (3%) 35 (6%) 0.32 

Total 196,552 10,824 602 0.30 (avg.) 

Source: GES 2005 and FARS 2005 data. 

Table 16 and Table 17 indicate the distribution of vehicle damage severities coded in the FARS 

database for belted and unbelted drivers of all large trucks and of Class 7 and 8 vehicles, 

respectively. The tables suggest that 95 percent of fatal crashes for all large trucks involve 

disabling damage to the vehicle, according to FARS researchers. For Class 7 and 8 trucks as 

shown in Table 17, some 96 percent were reported as having disabling damage. When 

populations of belted versus unbelted drivers are considered, little difference can be observed in 

the proportion with disabling versus functional damage, and it is likely that there are differences 

in crash severity that are not discernible. Some crashes in which the truck is coded as having 

disabling damage may be truly nonsurvivable for drivers of the large truck. Others may result in 

disabling damage, yet the vehicle occupant compartment remains intact. In identifying cases in 

which drivers would have survived had they worn their safety belts, the FARS data are of little 

use. Few additional data are collected by FARS researchers to accurately characterize the 

survival space and determine the mechanism of driver injury that led to death. Within section 

7.2, alternate sources are explored to determine how many fatally injured drivers of large trucks 

would have survived had they been wearing safety belts. 

Table 16. Vehicle Damage Severity Coded in FARS 

for Belted and Unbelted Drivers of All Large Trucks 

Unknown Unbelted Belted 

Total Number 

(% of total) 

Disabling 117 316 219 652 (95%) 

Functional 1 13 12 26 (4%) 

Other, Minor 0 4 0 4 (>1%) 

None 0 3 0 3 (>1%) 

Unknown 0 1 2 3 (>1%) 

Total 118 337 233 688 

 Source: FARS 2005 data. 

62 
Table 17. Vehicle Damage Severity Coded in FARS 

for Belted and Unbelted Drivers of Class 7 and 8 Trucks 

Unknown Unbelted Belted 

Total Number

(% of total) 

Disabling 115 266 196 577 (96%) 

Functional 1 8 7 16 (3%) 

Other, Minor 0 4 0 4 (>1%) 

Unknown 0 1 2 3 (>1%) 

None 0 2 0 2 (>1%) 

Total 116 281 205 602 

 Source: FARS 2005 data. 

7.1.2. Crash Environment Characteristics 

Roadway Types 

Table 18 and Table 19 show the distribution of crashes for all large trucks and for Class 7 and 8 

trucks by roadway type. Table 18 shows the number of fatalities for drivers of all large trucks by 

roadway type. FARS data indicated that the majority of fatal crashes (82 percent) in 2005 

occurred on highways, which includes interstates (40 percent), state highways (24 percent), and 

U.S. highways (19 percent). For those crashes in which the safety belt status was known, overall, 

59 percent were unbelted. The highest unbelted rate (known safety belt status) for drivers of all 

large trucks (10,001 pounds or more) was on municipality roadways (85 percent), followed by 

county roads, where 80 percent were unbelted. Table 19 shows similar results for Class 7 and 8 

drivers; drivers were unbelted in 58 percent of the fatal crashes in which the safety belt status 

was known. Forty-eight percent of Class 7 and Class 8 truck drivers who were fatally injured on 

interstate roadways were unbelted. 

Table 18. Fatal Crashes by Roadway Type for Drivers of All Large Trucks 

Roadway Type 

Unknown 

Safety Belt 

Status Unbelted Belted 

Unbelted, 

Known Safety 

Belt Status (%) 

Total 

Number 

(% of total) 

Interstate 60 104 109 49 273 (40%) 

State Highway 21 84 57 60 162 (24%) 

U.S. Highway 23 64 42 60 129 (19%) 

County Road 7 45 11 80 63 (9%) 

Other Local 6 10 5 67 21 (3%) 

Municipality 0 17 3 85 20 (3%) 

Other 1 13 6 68 20 (3%) 

Total 118 337 233 59 (avg.) 688 

 Source: FARS 2005 data. 

63 
Table 19. Fatal Crashes by Roadway Type for Drivers of Class 7 and 8 Trucks 

Roadway Type 

Unknown 

Safety Belt 

Status Unbelted Belted 

Unbelted, 

Known Safety 

Belt Status (%) 

Total 

Number 

(% of total) 

Interstate 60 92 101 48 253 (42%) 

State Highway 20 72 46 61 138 (23%) 

U.S. Highway 22 52 39 57 113(19%) 

County Road 7 37 8 82 52 (9%) 

Other Local 6 6 4 60 16 (3%) 

Municipality 0 12 2 86 14 (2%) 

Other 1 10 5 67 16 (3%) 

Total 116 281 205 58 (avg.) 602 

 Source: FARS 2005 data. 

Weather Conditions 

In 2005, the majority of the fatal CMV crashes occurred in “normal” weather conditions (88 

percent), as opposed to rainy (8 percent) or foggy (2 percent) weather. Table 20 and Table 21

show that there are few differences based on weather conditions between the belted and unbelted 

CMV driver populations for all large trucks and Class 7 and 8 trucks, respectively. 

Table 20. Fatal Crashes by Weather Conditions for Drivers of All Large Trucks 

Weather 

Conditions 

Unknown 

Safety Belt 

Status Unbelted Belted 

Unbelted, 

Known Safety 

Belt Status (%) 

Total Number

(% of total) 

Normal 98 301 204 60 603 (88%) 

Rain 12 28 13 68 53 (8%) 

Fog 3 5 7 42 15 (2%) 

Snow 3 3 4 43 10 (1%) 

Other 1 0 5 0 6 (<1%) 

Sleet 1 0 0 1 (<1%) 

Total 118 337 233 59 (avg.) 688 

 Source: FARS 2005 data. 

64 
Table 21. Fatal Crashes by Weather Conditions for Drivers of Class 7 and 8 Trucks 

Weather 

Conditions 

Unknown 

Safety Belt 

Status Unbelted Belted 

Unbelted, 

Known Safety 

Belt Status (%) 

Total Number

(% of total) 

Normal 96 249 180 58 525 (87%) 

Rain 12 24 10 71 46 (8%) 

Fog 3 5 6 45 14 (2%) 

Snow 3 3 4 43 10 (1%) 

Other 1 0 5 0 6 (<1%) 

Sleet 1 0 0 1(<1%) 

Total 116 281 205 58 (avg.) 602 

 Source: FARS 2005 data.

Time of Day 

Data shown in Figure 6 and Table 22 were aggregated for 2000–2005 data years to compile 

sufficient crash counts by hour to identify trends. Figure 6 shows that overall, driver fatalities 

most often occur during daytime hours (i.e., from 5 a.m. to 4 p.m.), and decline after 5 p.m. 

As shown in Table 22, within the population of fatally injured drivers of all large trucks, the 

lowest rate of safety belt use occurred from 3 p.m. to 6 p.m., when only 33 percent were belted. 

From 6 p.m. to 9 p.m., the belted percentage increased to 39 percent. From 9 p.m. to 12 p.m., 41 

percent were belted. From midnight to 3 a.m., the highest rates of safety belt use in the fatally 

injured population are observed—43 percent are belted. From 3 a.m. to 6 a.m., 42 percent are 

belted. From 6 a.m. to 9 a.m., the belted percentage drops to 38 percent. From 9 a.m. to 12 a.m., 

the percent of belted declines further to 36 percent. From noon to 3 p.m., this population is 35 

percent belted. When the percentage of belted drivers who die during nighttime crashes is 

compared with the proportion of drivers who die during daytime crashes, it appears that a larger 

proportion is belted at night. This is somewhat counterintuitive, since the risk of safety-belt-use 

enforcement should be higher during the day. 

65 
-30

20

70

120

170

220

Fatality Count (6 years)

Midnight

24

6:00 AM

8

10

Noon

24

6:00 PM

8

10

Time of Day

Belted

Unbelted

Figure 6. Fatalities by Time of Day and Belt Use for Drivers of All Large Trucks 

Source: FARS 2000–2005 data. 

Table 22. Fatalities by Time of Day and Belt Use for All Large Trucks 

Crash Time 

Unbelted, 

number (%) 

Belted, 

number (%) 

Midnight to 3 a.m. 126 (57%) 94 (43%) 

3 a.m. to 6 a.m. 233 (58%) 170 (42%) 

6 a.m. to 9 a.m. 263 (62%) 160 (38%) 

9 a.m. to 12 a.m. 329 (64%) 182 (36%) 

Noon to 3 p.m. 285 (65%) 156 (35%) 

3 p.m. to 6 p.m. 224 (67%) 109 (33%) 

6 p.m. to 6 p.m. 117 (61%) 76 (39%) 

9 p.m. to 12 p.m. 88 (59%) 60 (41%) 

 Source: FARS 2000–2005 data. 

The distribution of fatal crashes by time of day for Class 7 and 8 truck drivers is nearly identical 

to that shown in Figure 6 and Table 22. For this reason, these items are not presented here. 

7.1.3. Crash Vehicle Characteristics 

Table 23 shows the distribution of 2005 fatalities by cargo body type and by vehicle 

configuration (i.e., tractor trailer or single-unit truck). As shown, the majority of driver fatalities 

involve tractor trailers with a cargo body type designated as “van/enclosed box.”. It should be 

66 
noted that according to FHWA Annual Vehicle Distance Traveled statistics, each tractor trailer 

(Class 8 truck) travels an average of 74,245 miles per year, compared to 13,164 miles of annual 

travel for single-unit trucks. Due in part to this higher level of exposure, tractor trailers are more 

often involved in fatal crashes. Combination trucks are more often operated on higher-speed 

roadways (highways). It should be noted that even a slight increase in safety belt use by Class 8 

truck drivers will have a greater impact on injury and fatality counts for CMV drivers as 

compared to other vehicle segments (like smaller single-unit trucks). If 10 percent of the 

unbelted fatal population of tractor trailer drivers were belted during their crashes, 265 drivers 

would be affected (55 percent of 481 fatal drivers). However, if 10 percent of the unbelted fatally 

injured population of Class 7 single-unit truck drivers wore their belts, only 82 drivers would be 

affected (68 percent of 121 fatal drivers). 

Table 23 also shows that a larger percentage of single-unit-truck driver fatalities are sustained by 

unbelted drivers (68 percent of single-unit-truck fatalities are unbelted versus 55 percent of fatal 

truck/tractor drivers are unbelted). These percentages include fatal crashes where the driver’s 

safety belt status was known. The unbelted percentages shown in columns 3, 5, and 7 of Table 23

were calculated by dividing the number of unbelted fatally injured drivers by the number of 

fatally injured drivers whose safety belt use status was known for each vehicle configuration 

listed in the table. Each vehicle type category was derived directly from FARS-coded vehicle 

types. 

Table 23. Distribution of Driver Fatalities in 2005—Vehicle Configuration versus Cargo 

CARGO (Type 1) 

(Class 8) 

Fatalities 

(Class 8) 

Unbelted, 

Known 

Safety Belt 

Status (%) 

(Class 7) 

Fatalities 

(Class 7) 

Unbelted, 

Known 

Safety Belt 

Status (%) 

(NonClass 7 

and 8) 

Fatalities 

(Non-Class 7 

and 8) Unbelted, 

Known Safety 

Belt Status (%) 

Van/Enclosed Box 240 51 33 63 41 64 

Flatbed 58 48 11 59 17 71 

Cargo Tank 72 57 9 83 4 100 

Dump 27 59 33 69 6 67 

Unknown Truck 23 69 7 80 10 70 

Other Truck 25 62 6 91 6 80 

No Cargo Body 12 70 1 0 2 0 

Garbage/Refuse 5 66 9 100 0 0 

Grain/Gravel, etc. 12 64 2 50 0 0 

Concrete Mixer 0 0 10 70 0 0 

Pole 6 83 0 0 0 0 

Total 481 55 121 68 86 67 

1Vehicle types reported here are based on FARS 2005 codes. Source: FARS 2005 data. 

 Key: Class 8—Tractor Trailer, Class 7—Single-Unit Truck, Non-Class 7 and 8—Large Trucks (>10,000 pounds) 

7.1.4. Crash Occupant Characteristics 

Figure 7 shows the distribution of fatalities for drivers of all large trucks by age and safety belt 

use for the years 1995, 2000, and 2005. Within the youngest age category (drivers aged 20 to 34 

67 
years), the total number of fatalities decreased from 137 in 1995 to 108 in 2005. Conversely, for 

drivers aged 50 and older, the total number of fatalities increased from 153 in 1995 to 248 in 

2005. The increase in fatalities for drivers older than 50 years may reflect a general increase in 

the average age of drivers since 1995. The middle-aged group does not show any clear trend 

when 1995, 2000, and 2005 crash years are compared. 

When safety belt use is considered, the percent of unbelted drivers dying in crashes appears to 

have decreased since 1995 for all age groups. Overall, the youngest group of drivers (aged 20 to 

34) has the highest percentage of unbelted drivers when compared to the middle-aged and older 

age groups. This is true across all three years considered. 

The injury tolerance of older drivers is typically lower than that of the young and may influence 

the fatality rates shown here. If an older driver is involved in a crash of identical severity to that 

of a younger driver, the likelihood of death is higher for the older driver. It is possible that 

younger unbelted drivers may be surviving crashes that their older counterparts do not survive, 

and for this reason it is possible that the youngest drivers are unbelted even more frequently than 

suggested by Figure 7, when compared to the older group (50+ years old). 

Figure 7. Distribution of Class 7 and 8 Truck Driver Fatalities 

Source: FARS 2005. 

When driver gender was considered, it was discovered that only 22 of the 602 fatally injured 

drivers were females for Class 7 and 8 vehicles. For all large trucks, only 24 of the 688 drivers 

were female. The data indicated that, for Class 7 and 8 drivers, 36 percent (8 out of 22 fatally 

injured female drivers) were unbelted and for all large trucks, 33 percent (8 out of 24 fatally 

injured female drivers) of this small population was unbelted. This percentage of unbelted 

drivers is considerably lower when compared to the 60 percent of male drivers who are unbelted; 

68 
however, few reliable conclusions can be drawn from this difference due to the small number of 

female driver observations within the FARS dataset used to make the comparison. 

The impact of medical issues on fatalities was explored, including heart attacks, loss of 

consciousness, or other conditions where driver performance is affected. In 2005, FARS analysts 

indicated that medical conditions (including diabetic reactions, seizure, heart attack, high/low 

blood pressure, and fainting) were a crash-related factor in seven of the 602 Class 7 and 8 truck 

driver fatalities. It should be noted that the determination of medical factors is not 

straightforward, and this population may under-represent the actual impact of medical-related 

events. 

For the fatal population, few data are recorded by FARS analysts to describe the health of 

drivers. One health surrogate that can be calculated based on FARS data is the Body Mass Index 

or BMI. BMI is calculated by dividing body weight in kilograms by body height in meters 

squared and can be used as a surrogate measure of fitness for drivers. A BMI less than 27 is 

considered normal. A BMI between 27 and 31 is considered overweight and over 31 is 

considered obese. Figure 8 shows the distribution of BMI for fatally injured CMV drivers. As 

shown in Figure 8, some 53 out of a total of 84 (63 percent) normal BMI drivers were unbelted. 

For obese drivers, 98 out of 158 (62 percent) are unbelted. One claim made by drivers is that 

current safety belts do not comfortably fit larger or obese drivers and this leads to lower safety 

belt use rates by this demographic population. Compared with normal BMI drivers, the fatally 

injured population of overweight and obese drivers does not appear to contain larger proportions 

of unbelted drivers. It should be noted that BMI is only an approximation of driver size. 

Figure 8. Driver Body Mass Index (BMI) for Fatally Injured Drivers 

of All Large Trucks 

Source: FARS 2005 data. Note: BMI is an approximation of driver size. 

69 
7.2. CHARACTERISTICS OF FATALLY INJURED AND BELTED CMV DRIVERS 

Safety belts have been proven to be the most effective strategy to prevent fatalities for motor 

vehicle drivers and passengers; however, 41 percent of CMV drivers who died during crashes in 

2005 were wearing safety belts. These data were presented above, in Figure 6. The following 

analysis was conducted to better understand mechanisms of fatal injury for belted drivers, and 

how these fatal crashes involving belted drivers differ from other crashes in which belted drivers 

survived. 

To accomplish this, it was necessary to go beyond general characteristics of crashes as described 

previously and determine the primary sources or mechanisms of injury for fatal drivers. 

Unfortunately, within the FARS data, little information is collected to characterize the postcrash 

condition of vehicles, characteristics of the occupant compartment, and the mechanism of injury 

leading to death. 

In order to adequately assess this information, a review of the Large Truck Crash Causation 

Study (LTCCS) dataset was conducted as a part of this research. The dataset, described in more 

detail below, contains accurate information regarding crash conditions, the nature of injuries 

sustained, and the overall severity of each crash case collected. The analysis that was performed 

reviewed mechanisms for incapacitating and fatal injury cases. Incapacitating injury cases were 

reviewed along with fatal cases because the LTCCS data contain only a small sample of fatally 

injured driver cases. It was confirmed during the analysis that the conditions leading to serious 

injuries are similar to those resulting in death. In sections 7.2.3 and 7.2.4, an example case 

review and the findings from reviewing all of the unbelted fatal and serious-injury cases are 

provided to identify whether those fatally and seriously injured drivers would have sustained the 

same or lesser injuries had they been belted. 

7.2.1. Large Truck Crash Causation Study Data 

The LTCCS contains a sample of crashes where at least one large truck with a GVWR of 10,001 

pounds or more was involved in a crash that resulted in at least one K-, A-, or B-level injury. 

These are crashes in which one or more fatalities (K), an incapacitating injury (A), or a nonincapacitating (but evident) injury (B) were or was sustained by any occupant involved. Data for 

the sample were collected by National Accident Sampling System (NASS) personnel across 17 

sampling sites. Based on its probability of selection, each case collected was assigned a 

weighting factor and when weights were applied, it was possible to compute estimates that were 

representative of K-, A-, and B-level crashes involving large trucks across the entire country. 

The LTCCS dataset is a useful resource for this analysis due to the highly detailed data collected 

per case. As a result of ongoing cooperation with police in the 17 data collection sites around the 

country, researchers were rapidly informed of large-truck crashes and were able to initiate 

investigations soon after each crash occurred. Data collection was performed at each crash site 

by a two-person team consisting of a trained NASS researcher and a state truck inspector. While 

on the scene, crash-involved vehicle occupants and witnesses were interviewed. After the crash, 

each vehicle was subjected to a thorough inspection. Researchers also reviewed police crash 

reports, hospitals records, and coroners’ reports. For each case, up to 1,000 data elements were 

collected and coded. In addition, the crash scene and post-impact vehicles were photographed 

70 
extensively to document conditions. A scene sketch, drawn to scale, also provided a graphical 

overview of the environment, the crash scenario, and all known impact events. 

Table 24 and Table 25 provide a summary of LTCCS case counts by level of injury sustained by 

drivers. All individual injuries coded within the LTCCS are assigned an AIS code that uniquely 

identifies the body region, the details related to the anatomical structure involved, and the 

severity of the injury sustained. The AIS severity indicates the threat to life associated with a 

particular injury and ranges from 0 to 6 (where AIS 0 is uninjured, AIS 1 injury is minor, AIS 2 

is moderate, AIS 3 is serious, AIS 4 is severe, AIS 5 is critical, and AIS 6 is maximum or 

generally nonsurvivable). Results shown in the table are reported by maximum AIS (MAIS) per 

driver. Each driver is represented only once in the table based on his or her most severe injury, 

even if he or she sustained multiple injuries during the crash. 

The unweighted numbers in Table 24 indicate the raw number of cases collected by LTCCS 

investigators. Weighted counts in Table 25indicate national level estimates of large-truck crash 

counts where a K-, A-, or B-level injury was sustained by an occupant involved. Since it is 

impossible to conduct a detailed investigation of every truck crash occurring within the United 

States, a sample of crashes is selected and investigated. In order to relate those observations 

selected and investigated to the actual crash population, weights are assigned to each case. The 

sum of the weights for all cases reflects the total number of actual large-truck crashes occurring 

within the study period. 

Weighted and unweighted numbers are presented in Table 24 and Table 25 so that the reader is 

aware of the limited sample size with which this analysis was conducted. As shown in Table 24, 

the number of cases available where a moderate to serious injury was sustained by the largetruck driver is relatively small, including 59 MAIS 2 injured, 33 MAIS 3, 9 MAIS 4 , 4 MAIS 5 

and 43 MAIS 6 or fatally injured drivers. The population of injured is quite small compared to 

the population of uninjured and those who sustained only minor injuries. For this reason, in 

reviewing moderate- to serious-injury cases, only unweighted case counts are presented. 

Application of case weights to a small population of cases would likely result in spurious or 

unreliable estimates. 

As shown in Table 24 and Table 25, there are 64 unweighted cases where a belted driver 

sustained at least one AIS 2 or higher injury. These cases were selected for detailed review to 

determine the primary cause of the most serious injuries sustained. 

Table 24. Unweighted Driver Counts by MAIS Injury Levelfor Drivers of All Large Trucks 

MAIS Level Unknown Unbelted Belted Total 

Uninjured 56 83 628 767 

Minor (MAIS 1) 12 78 219 309 

Moderate (MAIS 2) 4 23 32 59 

Serious (MAIS 3) - 14 19 33 

Severe (MAIS 4) - 5 4 9 

Critical (MAIS 5) 1 2 1 4 

Maximum (MAIS 6) 12 23 8 43 

Total 85 228 911 1,224 

 Source: LTCCS 2000–2003 data. 

71 
Table 25. Weighted Driver Counts by MAIS Injury Level 

for Drivers of All Large Trucks 

MAIS Level Unknown Unbelted Belted Total 

Uninjured 4,384 7,484 64,421 76,288 

Minor (MAIS 1) 935 11,484 30,091 42,510 

Moderate (MAIS 2) 1,041 4,394 4,695 10,130 

Serious (MAIS 3) - 3,356 2,241 5,597 

Severe (MAIS 4) - 759 815 1,574 

Critical (MAIS 5) 39 321 160 520 

Maximum (MAIS 6) 721 908 457 2,086 

Total 7,120 28,706 102,880 138,704 

 Source: LTCCS 2000–2003 data. 

For each injured driver, a list of the injuries sustained was first compiled and sorted by body 

region involved (i.e., head, chest, abdomen, upper extremity, or lower extremity). For each 

unique injury coded, LTCCS researchers indicated the source of injury that identifies the interior 

or exterior component that most likely caused the injury. In addition, the code indicates if the 

injury was a noncontact injury. One missing data element in the LTCCS dataset is the degree of 

damage sustained by the truck. In particular, intrusion or collapse of the occupant survival space 

is not well-defined. In order to characterize the postcrash condition of the truck compartment, a 

case-by-case review of compartment photos was conducted and the damage severity was coded 

for the region immediately surrounding the occupant. 

There were 24 rollover crashes involving belted drivers within the LTCCS file in which MAIS 2 

and higher injuries occurred. Based on information gathered during the review, significant roofcrush and side structural damage occurred during all of these events. The resulting injuries were 

related to the intrusion. The LTCCS dataset contains 20 vehicle-to-vehicle crashes in which the 

driver sustained MAIS 2 and higher injuries. Based on clinical case reviews, it was determined 

that the majority of impact events involved the front of the case vehicle striking the rear of 

another truck. For each vehicle-to-fixed-object-collision reviewed, significant occupant 

compartment intrusion occurred or belted drivers were partially ejected, interacting with objects 

outside of the vehicle. Only two cases of vehicle–to-nonfixed-objects interaction were identified. 

One involved a train collision in which serious damage was sustained by the truck. The second 

involved a driver who was believed to have had a heart attack before the crash occurred. 

With the exception of the case of the driver who sustained a heart attack prior to the crash, the 

review showed that severe compartment intrusion was present for all frontal crash cases in which 

an MAIS 2 or higher injury was sustained. It should be noted that no cases were discovered 

where injuries were caused by driver interaction with the safety belts only. In all cases, direct 

contact injuries (with intruding interior or exterior components) were sustained. 

For cases in which side-loading occurred (during vehicle-to-vehicle or rollover collisions onto 

the vehicle’s side), safety belts were not effective in preventing serious injury or death. There 

72 
were 14 cases identified within the LTCCS dataset in which a belted driver sustained a moderate 

to serious injury under these conditions. 

7.2.2. Preventable Injuries and Fatalities with Safety Belt Use 

Further analysis of the LTCCS dataset was conducted to determine what impact safety belt use 

would have had on the population of unbelted drivers who were fatally or seriously injured 

during truck crashes. This evaluation was performed to address misconceptions regarding safety 

belts that were voiced by the stakeholders. One misconception is that safety belts will have little 

influence during large-truck-versus-passenger-vehicle crashes, because large trucks have a size 

advantage. Another misconception is that in crashes where an unbelted driver dies, the crashes 

are so severe that drivers are not likely to survive even with safety belt use. 

A detailed analysis of 70 crash cases was conducted where an unbelted large-truck driver was 

seriously injured or fatally injured during a crash. Clinical case reviews were conducted to 

determine what effect, if any, safety belt use would have had on a population of fatally and 

seriously injured CMV drivers who were not wearing safety belts. Case reviews were performed 

by two research team members with considerable backgrounds in crash analysis. The analysis 

was performed separately by each reviewer and results were compared for accuracy. All 

differences of opinion were discussed and re-categorized as agreed upon by both researchers. 

For each driver injured or killed, a list of the injuries sustained was generated and sorted by body 

region. For each unique injury coded, an injury source was also determined that identified the 

interior or exterior component that most likely caused the injury. In addition, the code indicates 

whether the injury was a contact or non-contact injury. This information is useful in determining 

the occupant kinematics or movement within a vehicle during a crash; however, no indication of 

intrusion or crash-induced interior damage to the truck is coded. For instance, if the steeringwheel rim was coded as the injury source for a particular chest injury, it is not possible to 

determine from the coded data if the steering-wheel rim intruded into the occupant’s survival 

space leading to the injury or if the unrestrained occupant made harmful contact with the steering 

column due to crash forces. 

To better understand the crash environment in which the injury occurred, interior and exterior 

vehicle crash photos were reviewed to estimate if direct contact with the injury source 

component would have occurred if the driver had been belted. For injuries that were AIS 2 and 

higher, injured body regions for unbelted occupants were categorized as preventable, possibly 

preventable, or non-preventable categories. In some cases, severe occupant compartment 

intrusions at the driver’s seating position occurred and the use of a safety belt would not likely 

have reduced the severity of injuries. Alternatively, if the vehicle interior structure remained 

intact and the survival space was maintained, direct contact injuries are flagged as potentially 

preventable or preventable if belted. 

Exterior damage was also assessed using vehicle photos to establish if crash forces were 

sufficiently severe that safety belt use would not have prevented or mitigated injuries, even in the 

absence of significant compartment intrusion in the area of the driver’s seating position. 

73 
As mentioned above, a large amount of data is coded for each LTCCS case; however, few 

measurable indicators of crash severity are collected for truck crashes. Traditional information, 

like crash deltaV, degree of compartment intrusion, and intrusion extent by component are 

unrecorded for truck crashes. 

7.2.3. Example Case Review 

Described in this section is an example of a case review involving a severely injured (MAIS 4), 

unbelted CMV driver who would likely have sustained only minor injuries during the crash had 

he been belted. LTCCS Case #813006030 occurred on a two-lane highway under rainy 

conditions. It involved two tractor trailers traveling in opposite directions. The collision was an 

offset frontal crash. This was evident by the external damage to both trucks. 

Within the two trucks were the drivers, one belted and one unbelted, and two passengers both of 

whom were belted. The belted occupants all sustained minor injuries (all AIS 1). The unbelted 

driver of the case vehicle was a 52-year-old male who sustained one AIS 4 injury and several 

AIS 3 injuries. His injuries included multiple rib fractures, associated hemo/pneumothorax, a 

lung contusion, and a splenic laceration. Each of these injuries was attributed to contact with the 

steering wheel and vehicle side structure during the offset collision. During the collision, this 

unbelted driver significantly interacted with the steering wheel (as evidenced by severe 

deformation of the steering wheel and column). This driver also sustained a loss of 

consciousness due to interaction with the steering mechanism or due to contact with the roof 

header. Four photographs, shown in Figure 9, Figure 10, Figure 11, and Figure 12, show the 

severity of the crash.

Figure 9. Interior Photo of Case Vehicle Showing 

Extensive Steering Deformation 

Source: 2000–2003 LTCCS data. 

74 
Figure 10. Interior Photo of the Principal Other Vehicle 

(Crash Partner) Showing no Steering Deformation 

Source: LTCCS 2000–2003 data. 

Figure 11. Exterior View of Case Vehicle Where Unbelted Driver Was Severely 

Injured (MAIS 4) and Belted Passenger Sustained Minor Injuries (MAIS 1) 

Source: LTCCS 2000–2003 data. 

75 
Figure 12. Exterior View of Principal Other Vehicle Where Both Belted 

Occupants Sustained Minor Injuries (MAIS 1) 

Source: LTCCS 2000–2003 data. 

Based on the vehicle photos, no passenger compartment intrusion occurred in either vehicle. The 

external damage is consistent with a frontal offset collision with a similar vehicle. The belted 

driver sustained only minor injuries during the crash and his steering wheel and column 

remained undamaged. Had the severely injured driver been belted, it is less likely that he would 

have come in contact with the steering column and rim. If he had, the degree of loading would 

have been significantly lower. This case shows that the use of a safety belt could have made a 

significant difference in the injury outcome for the CMV driver. 

7.2.4. Case Review Results 

Crashes from the LTCCS dataset in which unbelted CMV drivers were either severely injured or 

fatally injured were reviewed for the purpose of determining if the safety belt use would have 

mitigated the injury sustained or prevented a fatality from occurring. As shown in column 3 of 

Table 26, some 37 out of the 70 fatal- or serious-injury cases reviewed would have improved 

outcomes with belt use. For these cases, this included preventable deaths and injuries that might 

have been mitigated. Twenty-eight of the 47 moderate, serious, severe, or critical injuries (MAIS 

2 through MAIS 5) could have been mitigated to minor injuries with safety belt use, as shown in 

Table 26. Also shown in the table is that nine out of 23 fatalities (MAIS 6) would likely have 

been prevented if the driver had used the safety belt. These results are also shown with weighted 

values in Table 27. 

76 
Table 26. Potentially Preventable Deaths and 

Reduced Injuries if Safety Belts Had Been Used—Unweighted Counts 

Unweighted Counts Maybe No Yes (% MAIS) Total 

No Injury 0 0 0 0 

Minor Injury (MAIS 1) 0 0 0 0 

Moderate Injury (MAIS 2) 0 8 (35%) 15 (65%) 23 

Serious (MAIS 3) 2 (13%) 6 (40%) 7 (47%) 15 

Severe (MAIS 4) 0 2 (29%) 5 (71%) 7 

Critical (MAIS 5) 0 1 (50%) 1 (50%) 2 

Fatal (MAIS 6) 2 (9%) 12 (52%) 9 (39%) 23 

Total 4 (6%) 29 (41%) 37 (53%) 70 

 Source: LTCCS 2001–2003 data. 

Table 27. Potentially Preventable Deaths and 

Reduced Injuries if Safety Belts Had Been Used—Weighted Counts 

Weighted Counts Maybe No Yes (% MAIS) Total 

No Injury 0 0 0 0 

Minor Injury (MAIS 1) 0 0 0 0 

Moderate Injury (MAIS 2) 0 1,538 2,856 4,394 

Serious (MAIS 3) 770 1,281 1,503 3,554 

Severe (MAIS 4) 0 33 1,475 1,508 

Critical (MAIS 5) 0 0 321 321 

Fatal (MAIS 6) 85 339 484 908 

Total 855 3,191 6,639 10,685 

 Source: LTCCS 2001–2003 data. 

Most of the injuries that could have been mitigated or prevented were due to contact with the 

interior passenger compartment and not to intrusion. Contacts with the vehicle steering wheel, 

shift lever, windshield, dashboard, side doors, windows, and roof were common injury sources 

for unbelted drivers. When occupant ejection is considered, there are a small number of vehicles 

that are considered too compromised for the crash to be called survivable. The largest proportion 

of ejected occupants would have survived if they had remained within the vehicle. 

For unbelted occupants, column 4 in Table 28 shows that 19 (unweighted) of the unbelted drivers 

who sustained MAIS 2+ injuries were partially or fully ejected. Column 3 in Table 28 shows that 

based on this review of a small number of crash cases where complete or partial occupant 

ejection occurred, eight cases (42 percent of those ejected) are survivable and an additional three 

are potentially survivable, had the occupant been belted. The partial-ejection cases all involved 

partial ejection out of the driver side window where ground contact by the driver occurred during 

rollovers. During collisions with fixed objects and during vehicle-to-vehicle impacts, drivers 

77 
made contact with components of a striking vehicle or fixed objects while remaining in their 

seats. Injuries sustained during these events could not have been prevented with safety belt use. 

Table 28. Survivability by Ejection Occurrence for Unbelted Drivers 

Who Sustained MAIS 2+ Injuries—Effect of Safety Belt Use on Injury Mitigation 

Maybe No Yes Total 

Ejection Type (Unweighted) 

No Ejection 0 14 (45%) 17 (55%) 31 

Complete or Partial Ejection 3 (16%) 8 (42%) 8 (42%) 19 

Unknown 1 (5%) 6 (30%) 13 (65%) 20 

Unweighted Total 4 (6%) 28 (40%) 38 (54%) 70 

Ejection Type (Weighted) 

No Ejection 0 1,926 2,964 4,890 

Complete or Partial Ejection 99 233 1,336 1,668 

Unknown 756 1,032 2,339 4,127 

Weighted Total 855 3,191 6,639 10,685 

 Source: LTCCS 2001–2003 data. 

7.3. CHARACTERISTICS OF FATAL ROLLOVER CRASHES 

Using the LTCCS dataset, a general analysis of fatal and nonfatal rollover crashes involving 

large trucks was conducted to better understand their primary characteristics and causes. For this 

analysis, a rollover was defined as any event involving “one or more quarter-turns about the 

longitudinal axis of a vehicle” and a planar crash was defined as any event in which the vehicle 

does not roll over. 

An estimated 4 percent of all large-truck crashes involved rollovers, yet 223 drivers or 37 percent 

of all large-truck driver fatalities in 2005 occurred during crashes where rollover was identified 

as the most harmful event. An additional 96 drivers were fatally injured during crashes where a 

rollover occurred. In these cases, some other impact was classified as the most harmful event. 

The rate of fatality during rollovers is approximately three fatalities per 100 police-reported 

rollover crashes. This rate is four times higher than the fatality rate due to collisions with fixed 

objects and 25 times higher than the rate of fatality for drivers of large trucks during vehicle-tovehicle collisions. 

Table 29 shows the fatal occupant ejection counts for planar and rollover crashes by nonejected, 

ejected, belted, and unbelted CMV drivers. In 163 of the 319 rollover fatalities (51 percent), the 

occupants were unbelted. As shown in rows 2 and 5 of Table 29, within the unbelted group, 39 

of these were drivers of single-unit trucks and 124 of these were drivers of tractor trailers (Class 

8 trucks). Seventy-eight out of the 163 unbelted occupants (48 percent) were completely or 

partially ejected from the occupant survival space. 

78 
Table 29. Fatal Occupant Ejection Counts for Planar 

and Rollover Crashes of Class 7 and 8 Trucks 

Non-ejected Ejected Total 

Rollover Crashes 

Single-Unit Truck Unknown 9 3 12 

Single-Unit Truck Unbelted 18 21 39 

Single-Unit Truck Belted 25 0 25 

Tractor Trailer Unknown 26 11 37 

Tractor Trailer Unbelted 67 57 124 

Tractor Trailer Belted 75 7 82 

Rollover Total 319 

Non-rollover Crashes 

Single-Unit Truck Unknown 1 1 2 

Single-Unit Truck Unbelted 21 13 34 

Single-Unit Truck Belted 9 0 9 

Tractor Trailer Unknown 49 17 66 

Tractor Trailer Unbelted 64 19 83 

Tractor Trailer Belted 81 8 89 

Non-rollover Total 283 

 Source: FARS 2005 data. 

In general, rollover crashes involving Class 7 and 8 trucks occur most frequently on rural highspeed roadways. Table 30, based on FARS 2005 data, indicates that 191 driver fatalities occurred 

in these locations, representing 60 percent of all fatal rollover crashes involving Class 7 and 8 

trucks. This includes rural interstates (66 driver fatalities), rural state highways (79 driver 

fatalities), and rural U.S. highways (46 driver fatalities). 

Table 30. Driver Fatality Counts During Rollover Crashes 

by Roadway Type for Class 7 and 8 Trucks 

Roadway Type Rural Urban Total 

Interstate 66 36 102 

State Highway 79 13 92 

U.S. Highway 46 12 58 

Total High-Speed Roadway 191 60 252 

County Road 35 4 39 

Other 11 2 13 

Township 5 1 6 

Municipality 0 5 5 

Unknown 1 0 3 

Frontage Road 1 0 1 

Total Non-High-Speed Roadway 53 12 67 

Total 244 72 319 

 Source: FARS 2005 data. 

79 
Table 31 shows FARS 2005 data of fatal rollovers by roadway alignment. These data suggest 

that fatal rollovers occur most often on straight roadways (51 percent) and most often involve 

tractor trailers. Table 32 identifies vehicle configurations involved in rollover crashes by cargo 

type in FARS 2005 data. As shown, tractor trailers hauling enclosed vans are the vehicle type 

most frequently involved in fatal rollovers, followed by tractor trailers hauling cargo tanks. 

Table 31. Fatal Rollover Crashes by 

Roadway Alignment for Class 7 and 8 Trucks 

Roadway 

Alignment 

Truck with Tractor, 

Number (%) 

Single-Unit 

Truck, 

Number (%) 

Total 

Fatalities, 

Number (%) 

Straight 131 (54%) 50 (66%) 181 (57%) 

Curve 112 (46%) 25 (33%) 137 (43%) 

Unknown 0 1 (<1%) 1 (<1%) 

Total 243 76 319 

 Source: FARS 2005 data. 

Table 32. Fatal Rollover Crashes by Vehicle Configuration 

 and Cargo Type for Class 7 and 8 Trucks 

Cargo Type1

Truck With 

Tractor 

Single-Unit 

Truck 

Van/Enclosed Box 102 15 

Cargo Tank 55 8 

Dump 20 23 

Flatbed 23 7 

Other Truck/Bus 13 4 

Unknown Truck/Bus-type 8 3 

Concrete Mixer 0 9 

Garbage/Refuse 4 5 

Grain/Gravel, etc. 8 1 

No Cargo Body 7 1 

Pole 3 0 

Total 243 76 

1Cargo types and vehicle configurations reported here are based on FARS 2005 data. 

80 
7.4. ROLLOVER CRASH CAUSATION 

Rollover crashes occur under widely diverse conditions, and for each event, multiple causal 

factors are likely to play a part. Within the LTCCS dataset, the critical precrash event is selected 

by investigators, which is defined as the single event that made the crash unavoidable. 

This event is typically a factor that directly precedes the initiation of the rollover; however, 

multiple additional factors might exist that, if changed, would have prevented the rollover from 

occurring. For example, if a rollover occurred while a truck was initiating a turn at an 

intersection, the critical precrash event might have been coded as “turning left at intersection.” 

But if data collected on-scene indicated that the driver was inattentive and failed to recognize the 

upcoming intersection or that the driver might have been traveling too fast for an upcoming 

curve, then these conditions can also be considered causal factors. 

It is difficult to analyze the chain of events leading to the onset of crashes like rollovers. Rather, 

a more useful approach is to identify all influential environmental-, vehicle-, or occupant-related 

causal factors for each case and later perform a factor analysis on the complete dataset to identify 

the most frequently recurring factors. This approach, applied in the following text, results in an 

expanded set of factors upon which to estimate crash causes for rollovers. 

Table 33 shows the distribution of truck types involved in rollovers as coded in the LTCCS. As 

shown in the table, the majority of cases are rollovers involving combination trucks (147 

unweighted cases). This trend reflects rollover involvement from the FARS (see Table 29). 

Physical causes, including those involving parts of the truck, the condition of the road, or 

elements of the surrounding environment, are generally apparent through study of the crash 

scene. However, the behavior of drivers is transitory, and the causes of the drivers’ errors must 

be inferred through information supplied by witnesses coupled with detailed analysis of the crash 

scene. The depth of analysis employed in the LTCCS makes it unique in revealing events 

precipitating large-truck crashes. For each of the crashes, the database provides case narratives, 

diagrammatic representation of crash events, and scene photos to help in reconstructing the crash 

situations, allowing analysts to make inferences as to the cause. 

Table 33. CMV Rollover Crashes by Body Type 

Truck Type Unweighted Weighted Counts Weighted % of Total

Combo Truck: Tractor Pulling Trailer 147 25,274 69 

Single-Unit: Three or More Axles 43 4,913 13 

Single-Unit: Two Axles 30 4,055 11 

Combo Truck: Tractor Pulling Two Trailers 10 1,077 3 

Combo Truck: Truck Pulling Trailers 5 665 2 

Combo Truck: Truck Tractor Bobtail 5 286 1 

Other/Unknown/Missing 2 230 1 

Total 242 36,500 100 

Source: LTCCS 2001–2003 data. 

81 
The underlying causes of 242 rollover incidents were analyzed—incidents which made up almost 

a quarter of the total LTCCS sample. The analysis was undertaken to isolate the specific causes 

of rollover crashes, which could be expected to vary significantly from those causes that 

prevailed across the full array of large-truck crashes. The differences could help to identify 

preventive approaches that are aimed specifically at reductions in rollovers. 

The methodology employed in the rollover analysis included: (1) selecting the overall level of 

causation or reason category, (2) identifying causes, (3) aggregating causes, and (4) analyzing 

rollover results. The contributors to large-truck rollovers and the means used to identify them 

were analyzed at two levels. 

One level addresses the immediate crash predecessors having a readily identifiable effect in 

leading to the crash. The LTCCS database revealed that about three-quarters of truck crashes 

were due to inadequacies of drivers in recognition of, decisions about, and performance in 

handling threats to safety encountered on the road. The remainder stemmed from problems 

involving the condition of drivers before the crash occurred, the vehicles being driven, the road 

being driven on, and the weather. The specific causes were identified by LTCCS investigators at 

the scene and through interviews with drivers and witnesses. 

The second level of causation involves influences that are too remote in the causal chain to be 

identified through analysis of the crashes themselves. These include general characteristics of the 

driver (e.g., age, experience, and previous driving record), the vehicle (e.g., make, equipment), or 

the road (e.g., number of lanes, traffic controls). The effects of these influences, referred to as 

associated factors, were selected from a broad range of factors thought to contribute to crash risk. 

No judgment was made by LTCCS crash investigators as to whether any factor was related to the 

particular crash, just whether it was present (FMCSA, 2006). 

During the review, the following major categories were identified that adequately characterize 

the types of influential factors observed. These include: speed, fatigue/attention/distraction, 

search, vehicle control, preoperative requirements, and other vehicles. Additional “causes” arose 

from problems with the vehicle that rolled over, including issues related to poor maintenance, 

load securement, and safety component failure. There were no problems with the road other than 

slippery surfaces, which only become a crash cause when drivers fail to adjust speed to surface 

friction. Since about two-thirds of the incidents involved more than one cause, the total 

frequencies of causes adds up to more than the number of rollovers. The individual causes, 

which make up the final classification system, are presented in the next section, along with the 

frequencies associated with each. 

It should be noted that this review identified frequency of factors present when a rollover crash 

occurs based on unweighted LTCCS case counts. The review is intended to highlight the 

prevalence of each cause. The frequencies and population percentages presented should not be 

considered representative of the total CMV rollover crash population, due to the limited number 

of cases used to perform the analysis. 

Most of the rollovers were the result of mistakes on the part of the truck drivers, although some 

were “caused” by drivers of other vehicles and by those responsible for loading the trucks. A 

small number of rollovers occurred due to problems with the vehicle itself. In most cases, the 

82 
driver was aware of the particular problem and could have driven in such a manner as to prevent 

the rollover. In such instances, both the vehicle problem and the driver’s failure to accommodate 

to it through safer driving were considered causes, since preventing either of them would have 

avoided the rollover. The same treatment is used for slippery or otherwise unsafe road surfaces, 

except that the only practical means of dealing with these is by adjusting speed and control of the 

vehicle accordingly. On some occasions, a rollover is the result of an unsuccessful attempt to 

overcome a situation created by an earlier error. For example, inattention can lead to a potential 

crash situation in which a driver avoids a collision by a quick turn. If the truck rolls over, the 

cause was the driver’s inattention. The quick turn was not an error in this case, since it averted 

what would have been an equally serious, if not more serious, outcome. Table 34 shows the 

breakdown of “causes” of CMV rollovers identified in this LTCCS (2001–2003) review. As 

shown in the table, speed was the most frequent associated cause of rollover crashes (45 percent 

of LTCCS rollovers), followed by control-related (17 percent), and the category including 

fatigue, attention, and distraction (16 percent). Each of the categories shown in Table 34 and 

their subcategories are described in sections 7.4.1–7.4.7 in more detail. It should be noted that 

multiple causal factors may be assigned to each of the 242 rollover crashes, resulting in a total of 

379 factors shown in Table 34. 

Table 34. Causal Factors During CMV Rollover Crashes 

Cause of CMV Rollover Count % 

Speed 171 45 

Fatigue, Attention, and Distraction 61 16 

Control 66 17 

Visual Search 9 3 

Preoperation 22 6 

Other Drivers 37 10 

Vehicle 13 3 

Total 379 100 

 Source: LTCCS 2001–2003 data. 

7.4.1. Speed 

Review of the LTCCS dataset (2001–2003) identified that speed is the biggest contributor to 

rollover crashes (45 percent). Table 35 identifies speed-related factors associated with the onset 

of rollovers. This greatly exceeds the 23 percent of all large-truck accidents attributed to 

“traveling too fast for conditions” for all large-truck crashes (FMCSA, 2006). Since large trucks 

have a high center of gravity, vehicle speeds required to initiate rollover on a curve are quite low. 

Further, large trucks operate chiefly on interstates and other high-speed roadways. As with 

speed-related incidents in general, it is not the very high speeds associated with “reckless” 

driving, but rather speed that exceeds what is safe for the particular combination of vehicles and 

roads. 

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Table 35. Causal Factors Related to Speed Occurring During Rollover Crashes 

Involving Drivers of All Large Trucks Sorted by Frequency of Occurrence 

Rollover Factor Related to Speed 

Frequency 

of 

Occurrence 

Rollovers 

Related to 

Speed (%) 

Rollovers 

Reviewed in 

LTCCS, 

%(N=242) 

Misjudged the speed at which the curve could be 

taken 

71 42 29 

Not adjusting speed to load (stability, weight, or 

height) 

30 18 12 

In a hurry and disregarded speed limitation 17 10 7 

Not adjusting speed to known bad brakes 15 9 6 

Not adjusting speed to road conditions (slippery 

surface, grade) 

12 7 5 

Not adjusting speed to sharp turn at intersection 9 5 4 

Did not notice sign or other speed-limiting 

information 

5 3 2 

Not adjusting speed to vehicles ahead 4 2 2 

Aggressiveness toward other road users 3 2 1 

Not adjusting speed to worn tire tread 3 2 1 

Not adjusting speed to limited sight distance 2 1 <1 

Total 171 100 

Source: LTCCS 2001–2003 data. 

Curves 

It is in handling curves that excess speed becomes the biggest factor, accounting for 71 rollovers, 

which is more than two-thirds of all those that are speed-related. Trucks with tractors appear the 

most vulnerable to curves. Straight trucks or single-unit trucks, which make up 24 percent of the 

all trucks involved in rollovers (see Table 29), have 33 percent of their crashes on curves, 

compared to 46 percent on curves for trucks with tractors (see Table 31). This reflects the 

relatively lower roll stability of the trailer. 

Because the reasons drivers exceeded safe speeds on curves differ substantially, they are further 

subcategorized. The single biggest cause is simply misjudging the speed at which the curve can 

be safely entered. The single biggest rollover sources are the off-ramps of interstates and other 

high-speed highways where drivers carry too much speed onto the ramp. In some cases, it is the 

centripetal force that causes the truck to roll; in others, the truck drifts off the paved surface with 

a tire or the tires catch a structure or soft surface. In slightly more than half the cases, one or 

more other errors contributed to the rollover. 

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Loads 

Thirty rollovers were the result of loads that were too heavy, insecurely fastened, or mounted too 

high in the truck. The effect of loads is evident in the fact that they have twice the effect on 

rollovers as other truck crashes. The effect of a cargo improperly loaded is experienced most 

often on curves, where the combination of speed and rate of turn creates a centripetal force 

sufficient to roll the truck over. However, some occurred in a lane change, with a wheel dropping 

off the pavement or with a cargo shift unrelated to the motion of the truck. In 18 cases, the 

overloads were combined with misjudgment of safe speed; had the driver either prevented the 

overload or reduced speed accordingly, the rollover might not have occurred. 

Brakes 

In 15 cases, the condition of the brakes prevented slowing down enough to avoid the rollover. 

The cases were fairly equally divided among curves, intersections, and steep downgrades. In four 

instances, bad brakes combined with misjudgment of maximum safe speed resulted in rollovers 

on curves. In all of these instances, the truck had been driven long and far enough for the drivers 

to be aware of the problem and to have accommodated for it by reducing speed. The drivers’ 

failure to slow down is just as much a cause as the bad brakes. 

Roads 

Features of the road contributing to 12 rollovers were slippery surfaces (6), long downgrades (5), 

and a construction area (1). In all cases, the driver was aware of the safety threat posed and could 

have prevented the rollover situation by reducing speed, either by downshifting before starting 

downgrades or by earlier braking on slippery surfaces. As noted earlier, since nothing could be 

reasonably done to alter the condition of the road itself, it is not considered a cause. 

Intersections 

The nine intersection rollovers were a result of going too fast to make turns when trying to beat a 

traffic light, when unexpectedly encountering a T-intersection, or when making a last-second 

turn at a cross road (where a better choice would have been to keep going and then come back). 

Vehicles 

Four rollovers occurred when drivers failed to realize early enough that vehicles ahead had 

slowed and they were unable to stop in time. The primary cause was inattention, with one case 

due to insufficient following distance. 

Tires 

Three rollovers involved failure of the driver to adjust speed to account for worn tire tread, two 

in curves and one on a slippery surface. 

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Sight Distance 

On two occasions, trucks approached the top of a hill and failed to reduce speed to accommodate 

for the limited sight distance. Upon seeing stalled traffic, they swerved sharply and rolled over. 

7.4.2. Fatigue, Attention, and Distraction 

Second to speed as a contributor to rollovers is the category including fatigue, attention, and 

distraction. Sixty-one instances were the result of these issues, as listed in Table 36. 

Table 36. Causal Factors Related to Fatigue, Attention, and 

Distraction Occurring During Rollover Crashes Involving Drivers of All Large Trucks 

Rollover Factor 

Frequency 

of 

Occurrence 

Rollovers 

Related to 

Attention (%) 

Rollovers Reviewed 

in LTCCS, % 

(N=242) 

Not paying attention ahead or to other 

danger source 

26 43 11 

Being asleep or drowsy enough to be 

unaware 

22 36 9 

Driver distracted (passengers, phones, 

sounds, etc.) 

13 21 5 

Total 61 100 

 Source: LTCCS 2001–2003 data. 

Inattention 

The leading attention problem, inattention (in 26 rollovers), was simply not being observant in 

regard to what was going on ahead of the truck. This necessitated a sudden change in direction, 

leading to a rollover. In 12 of the cases, lack of attention was the only cause reported. The 11 

percent of rollovers resulting from inattention is close to the 8.5 percent reported for all largetruck crashes. However, this is a smaller degree of involvement than that which occurs with 

motor vehicles in general. This is a finding less likely to be attributable to the alertness of those 

who drive large trucks than to the reduced attention demands of driving primarily on open 

highways outside of city and suburban traffic. 

Sleep 

Sleep is the second most frequent source of attention loss (22 of 61 cases). Falling asleep at the 

wheel, or at least becoming sufficiently drowsy to make the driver unaware of what was 

happening, accounts for this inattention. In some cases, it could be attributed to the time of day 

(early morning) or length of time without sleep, but the source was difficult to pin down in most 

cases. The most frequent result was drifting off the road and overturning; however, in six 

instances, the driver suddenly became aware of having left the road, attempted to steer back on, 

and rolled over on the road. 

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Distraction 

The remaining attention problem is distraction, with 13 cases (5.4 percent). This is not far below 

the 8.5 percent involvement for all large trucks. The most common distractions were 

passengers—talking to or looking at them. Others included cell phones, CBs, tuning the radio, 

and hearing a strange sound. There were a few additional cases in which drivers reported a 

distraction, but the rollover cause lay elsewhere. 

7.4.3. Control 

Errors in controlling the motions of the truck were a factor in 47 rollovers, as shown in Table 37

(overcorrecting, improper steering, and improper braking). Of the responses needed to control 

the truck, steering was the most prone to errors, resulting in rollovers. Although failure to steer in 

a way that would keep the truck on the road was a frequent problem, an equal contributor to 

rollovers was overcorrecting (going one direction and quickly turning in the other direction). 

Maintaining adequate following distance, downshifting, and braking were smaller problems. 

Table 37. Causal Factors Related to Control Occurring During 

Rollover Crashes Involving Drivers of All Large Trucks 

Rollover Factor 

Frequency 

of 

Occurrence 

Rollovers 

Related to 

Control (%) 

Rollovers Reviewed 

in LTCCS, % 

(N=242) 

Overcorrecting after an error (offroad, wrong 

lane) 

24 36 10 

Lack of proper steering (over-/understeering) 19 29 8 

Failure to keep adequate distance from vehicle 

ahead 

9 14 4 

Responding to vehicles/road incorrectly 7 11 3 

Improper braking (e.g., locked brakes) 4 6 2 

Failure to downshift for speed control 3 4 1 

Total 66 100 

Source: LTCCS 2001–2003 data. 

Steering 

Poor steering control, including understeering or oversteering control, led to 19 rollovers. About 

half of these cases involved simple oversteering during lane changes and swerving more sharply 

than necessary to avoid trouble. Most of the remainder involved marginal steering control with 

difficulty staying in the lane, and two occurred in turning corners. 

Overcorrection 

Nineteen rollovers were the result of steering corrections—that is, turns in one direction followed 

by corrective turns that exceeded the stability of the truck. Situations leading to and coupled with 

overcorrection were falling asleep, inattention, steering errors, and distractions. 

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Following Distance 

Nine rollovers occurred when trucks were overtaking the vehicles ahead of them. The vehicle 

was forced to turn sharply and rolled over. Had the truck been following at a reasonable distance, 

there would have been enough space to stop or make a gradual lane change. In three of these 

cases, better steering control might have prevented the rollover. 

Maneuvering 

In seven cases, the truck driver chose a maneuver that was inappropriate based upon faulty 

perception, false assumption, or just a poor decision. 

Braking 

Locking the brakes was considered a contributing factor in four rollovers in which some other 

error created the situation that led to the braking. In several other incidents, locked brakes were 

involved in loss of directional control and in long stopping distances. However, braking was not 

cited as a contributing factor, nor was it possible to tell whether the rollover might have been 

prevented with better brake application. 

Downshifting 

While going down long or steep hills, three drivers failed to put the truck in low gear and were 

unable to control speed by brakes alone. 

7.4.4. Visual Search 

Lack of adequate visual search (i.e., not looking in the right place at the right time), contributed 

to nine rollovers, as shown in Table 38 (some 3 percent of the total population of rollover crash 

causes, per Table 34). It should be noted that search-related factors occurred infrequently within 

the sample of rollover cases reviewed. However, it appears that visual search is less often a 

factor during rollover crashes than it is for all other crash types (nonrollovers) involving CMVs. 

Lack of adequate search was associated with 13 percent of the 1,090 crashes within the LTCCS 

dataset as reported by FMCSA (2006). This difference is due to the fact that most rollovers occur 

on interstates and other major highways where travel speeds are higher. 

Table 38. Causal Factors Related to Visual Search 

During Rollover Crashes Involving Drivers of All Large Trucks 

Rollover Factor 

Frequency of 

Occurrence 

Rollovers 

Related to 

Search (%) 

Rollovers Reviewed in 

LTCCS, % 

(N=242) 

Not looking to the side at 

intersection, lane changes 

7 78 3 

Not looking far enough ahead, 

roadside 

2 22 <1 

Total 9 100 

Source: LTCCS 2001–2003 data. 

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Search to the Side 

Seven rollovers involving failure to search to the side were divided equally between initiating 

lane changes and crossing intersections. In one additional case, a driver turned across a railroad 

track where flashing lights signaled an approaching train. He assumed it was delivering to a local 

service area and did not look closely enough to judge its speed. 

Search Ahead 

The two situations involving failure to look far enough ahead involved one in which the driver’s 

attention was diverted to the rearview mirror and one in which the driver was focused on the 

road directly in front of the truck. In most cases, the failures to respond to threats in the path 

ahead were the result of attention lapses rather than inadequate search. 

7.4.5. Preoperation 

Table 39 describes two categories of rollover resulting from conditions that existed at the time 

the truck took the road (i.e., the way the truck was loaded and the driver’s mental and physical 

condition). 

Table 39. Causal Factors Related to Preoperation During 

Rollover Crashes Involving Drivers of All Large Trucks 

Rollover Factor Frequency

Rollovers Related to 

Preoperation (%) 

Rollovers Reviewed in 

LTCCS, % 

(N=242) 

Height or security of load driver’s 

responsibility 

16 73 7 

Mental or physical condition of 

driver causes rollover 

6 27 2 

Total 22 100 

Source: LTCCS 2001–2003 data. 

Loading 

In 16 of the rollovers caused by failure to adjust speed in curves to the load, the problem could 

have been avoided by better securing the load. Had the load not been allowed to shift, the truck 

would have remained upright, and in these instances, it was the driver’s responsibility to make 

sure the load was properly secured before starting out. In the remaining instances the problem lay 

in the height, weight, or nature of the load itself (e.g., fluids), and reducing speed would have 

been the only preventive measure. 

Driver State 

Six rollovers occurred when drivers lost consciousness due to a physical ailment or the 

medication used to treat it. One instance of falling asleep appears to have been the result of 

medication. All of these were not new conditions and might not have become a rollover cause 

had drivers taken steps to prevent their occurring when they were behind the wheel. 

89 
7.4.6. Other Drivers 

In all of the rollovers that have been described up to this point, the incident could be attributed to 

some mistake on the part of the person operating the truck. There were, however, 37 rollovers 

that were the fault of another driver, as shown in Table 40. 

Table 40. Other Causal Factors Occurring During Rollover 

Crashes Involving Drivers of All Large Trucks 

Rollover Factor Frequency 

Rollovers Related to 

Other Drivers (%) 

Rollovers Reviewed in 

LTCCS, % (N=242) 

Struck by another driver 33 89 14 

Caused by another driver 4 11 2 

Total 37 100 

Source: LTCCS 2001–2003 data. 

Struck By 

Of all the rollovers, 33 resulted from the truck being struck by another vehicle. The incidents 

included oncoming or passing vehicles turning into the truck’s lane, and vehicles coming from 

the side at crossroads and entrances. In none of these cases could the truck driver have been 

reasonably expected to avoid being hit. 

Caused By 

In four cases, the truck was not struck but rolled over in the process of avoiding a collision with 

another vehicle. The situations were largely the same as those in which the truck was struck, and, 

again, the truck driver could not have prevented the rollover. 

7.4.7. Vehicle 

Table 41 shows the frequency of vehicle-related rollover causes. The four factors are described 

below. 

Table 41. Causal Factors Related to the Vehicle Occurring 

During Rollover Crashes Involving Drivers of All Large Trucks 

Rollover Factor Frequency 

Rollovers Related to 

Vehicle (%) 

Rollovers Reviewed in 

LTCCS, % (N=242) 

Caused by poor tread and blowout 5 39 2 

Vehicle load insecure or too high 4 31 2 

Caused by sudden brake failure 2 15 <1 

Part failure unable to be 

anticipated/controlled by driver 

2 15 <1 

Total 13 100 

Source: LTCCS 2001–2003 data. 

90 
Tire Failure 

In addition to the three rollovers due to speed and worn tires (Table 35), five were the result of 

blowouts that did not involve any visible defects in the tire that would have caused tire failure to 

be anticipated by drivers. 

Loads 

Of the rollovers resulting from the way the truck was loaded, four cases involved trucks that 

were loaded prior to the drivers being assigned to them. Therefore, the load could be considered 

part of the vehicle. 

Brake Failure 

Two rollovers occurred when brakes suddenly failed on long downgrades. In neither case did the 

driver have reason to suspect a problem and possibly shift to a lower gear before beginning the 

descent. 

Part Failure 

Two rollovers were caused by part failures, one in the steering mechanism and one in a rear axle. 

91 
8. CONCLUSIONS 

The overall goal of this study was to identify and evaluate promising technologies designed to 

increase safety belt use by CMV drivers. In total, 13 technologies were identified and classified 

in three category types as follows: 

Reminder Systems: 

1. Dash Warning Light/Telltale (Passive System) 

2. Intermittent Dash Warning Light/Telltale (Active System) 

3. Audible Reminder (Passive System) 

4. Enhanced Audible Reminder (Active System) 

5. Transmission Interlock System 

Comfort Strategies: 

1. Safety Belt Tension Adjustors 

2. D-Ring Height Adjustors 

3. Seat-Integrated Safety Restraint System 

4. Safety Belt Covers 

Enforcement Strategies: 

1. Brightly Colored Safety Belts 

2. Onboard Data Recorders 

3. Exterior Safety Belt Use Indicator 

4. Driver Monitoring Stickers 

These technologies were identified through a review of existing scientific literature and through 

interactions with industry sources. Stakeholder information helped the research team to gain 

insight into strengths and weaknesses of each approach and provided insight regarding the most 

promising systems. Unintended consequences of each device were considered and alternative 

systems were explored during the stakeholder discussions. A BCA was performed considering 

the tradeoff between estimated aftermarket costs for each promising system and the anticipated 

reductions in injury with increased safety belt wearing if each device was introduced. Overall 

technology results were presented in Chapter 6. 

Promising Safety Belt Technologies: Based on information provided by industry stakeholders 

and drivers, the four most promising systems were: (1) Enhanced Audible Reminder System, (2) 

Brightly Colored Safety Belt System, (3) Safety Belt Tension Adjustor, and (4) Seat-Integrated 

Safety Restraint System. 

Enhanced Audible Reminder Systems appear to be the most promising technology based on 

research performed here. The technology is well understood and is readily available for 

integration into CMVs as needed. These systems are widely available today in passenger 

92 
vehicles. Further, the systems do not require additional enforcement or management activities in 

order to increase safety belt use. For this reason, these devices would be equally effective in all 

types of carrier operations. It is important to note that, for vehicles with a GVWR of 10,001 lbs 

or more, no visual or audible safety belt reminders are required by NHTSA’s Federal Motor 

Vehicle Safety Standards. Conversely, NHTSA has required safety belt reminder systems in 

passenger vehicles since 1974. 

Brightly colored safety belts were also found to be a promising technology to improve the rate of 

safety belt use by drivers of large trucks. The strategy facilitates enforcement of existing safetybelt-use laws by safety officials and law enforcement as well as enforcement of corporate 

policies by fleet safety managers. The technology is the least expensive device of those 

considered most promising during this study. Currently, a growing number of fleet owners are 

voluntarily choosing to equip their vehicles with these safety belts. The systems provide some 

visual cues to drivers so that they buckle up, yet they rely primarily on the perceived threat of 

enforcement in order to be effective. In addition, installation of these systems in fleet vehicles 

provides drivers with a clear indication of a company’s commitment to their drivers’ safety. At 

this time, little is known about the relative effectiveness of brightly colored safety belts in 

increasing safety belt use by CMV drivers; however, preliminary indications by fleet safety 

managers have suggested considerable increases in safety belt use rates when they are available 

in the vehicle. This increase relies somewhat on the implementation of a concurrent driver 

education program and rigorous enforcement of corporate safety guidelines requiring driver 

safety belt use once the brightly colored belts are installed. 

The third technology identified was the safety belt tension adjustor, commonly known as the 

Komfort Latch. This device, when used correctly, can aid drivers in configuring safety belt 

systems for optimized comfort. The technology is currently factory-installed by the vehicle 

manufacturer in close to 90 percent of new Class 8 vehicles sold in the United States according 

to restraint manufacturer information. The deployment of this strategy in a vehicle or fleet of 

vehicles must be accompanied by driver education regarding the proper use of the systems and 

regarding the value of safety belt wearing in preventing serious injuries or death during crashes. 

The Komfort Latch adds a variable amount of slack to the safety belt system in order improve 

driver comfort. The amount of slack that is added can be selected by the driver. The ability to 

add slack may increase belt wearing rates due to improvements in safety belt comfort; however, 

the injury-reducing effectiveness of the safety belt system may be reduced with added slack in 

the event of a crash. 

The final device considered promising is the seat-integrated safety restraint system. This 

technology was favored by vehicle manufacturers in particular. These systems have safety belt 

anchorages integrated into the seat structure so that relative motion between a suspended seat and 

a fixed safety belt is eliminated or reduced significantly. This technology is expensive and not 

yet ready for deployment; however, in the future, these systems could help to alleviate comfort 

concerns by drivers without degrading restraint system performance. Implementation of such a 

system would require extensive field evaluation to confirm that the devices do improve comfort 

overall. Further, crashworthiness evaluations should be conducted to determine if the addition of 

such a system does not degrade the protection of occupants during high-severity frontal crashes 

or during other common crash scenarios involving trucks. 

93 
Vehicle manufacturers have indicated that implementation of the enhanced audible reminder 

systems, brightly colored safety belts, or safety belt tension adjustors do not pose a technical 

challenge, yet these systems will not be implemented without sufficient market demand or 

pressure due to regulatory requirements. Seat-integrated safety restraints, however, would 

require significant resources before implementation, including some vehicle redesign and safety 

testing to verify their performance. 

Cost Benefit Analysis: A detailed cost benefit analysis was performed to estimate injury cost 

savings likely as safety-belt-wearing rates for drivers of large trucks increased. This cost savings 

was then compared with likely costs for each of the four most promising systems. Results of this 

analysis were presented in Chapter 6. 

The cost analysis was performed for drivers of all large trucks/CMVs and for drivers of Class 7 

and 8 vehicles specifically considering frequency and average injury costs for belted versus 

unbelted driver populations. Overall, the review indicated that $675 million could be saved 

annually if all unbelted drivers of large trucks were wearing safety belts during their crashes. For 

Class 7 and 8 drivers alone, $489 million in injury and fatality costs could be saved. The BCR 

for the least expensive technology option (i.e., brightly colored safety belts) was 1.7 for all large 

trucks and 4.5 for Class 7 and 8 trucks. This ratio suggests that for every dollar spent equipping 

vehicles with brightly colored safety belt systems, a return of $1.70 in injury costs savings can be 

expected due to increased safety belt use for all trucks. For Class 7 and 8 trucks, a return of $4.50 

is expected for every dollar spent equipping trucks with the devices. This calculation assumes 

that brightly colored safety belts would lead to a 10 percent increase in safety-belt-wearing rates 

of drivers of all large trucks. The BCR for the enhanced audible reminder system was 2.6 for all 

trucks and 6.9 for Class 7 and 8 trucks, assuming that the devices are 15 percent effective in 

increasing safety belt use rates. The safety belt tension adjusters had a BCR of 0.73 for all large 

trucks and 1.93 for Class 7 and 8 trucks. This assumes that the device would to lead to a 5-

percent increase in safety belt use. Finally, the seat-integrated restraint system, assumed to 

increase safety belt wearing rates by 5 percent, had a BCR of 0.26 for all trucks and 0.69 for 

Class 7 and 8 trucks alone. Overall, this BCR indicates that investing in seat-integrated restraint 

systems is not cost-beneficial at current device costs ($970/seat) if the anticipated increase in 

safety-belt-wearing rate is only 5 percent. If other concurrent improvements are realized by the 

introduction of these devices, the BCR would further improve. 

The BCA relies on estimates of device effectiveness. For these calculations, effectiveness values 

used were based on industry stakeholder estimates and estimates of the research team. Additional 

analyses are required to determine the exact changes in safety-belt-use behavior that would result 

from widespread deployment of each device. Some devices, like the safety belt tension adjustor, 

require driver instruction before any change in wearing rates would occur, as these devices are 

already widely available to drivers. A more detailed cost-based analysis, taking into account the 

cost of training, may be appropriate. The training curriculum could be developed by fleet safety 

personnel, or a standardized safety training course could be developed and disseminated by 

FMCSA or other interested parties. 

Crash Data Analysis: Crash data analysis results provide an overview of unbelted and belted 

populations of drivers of all large trucks who are fatally injured. The analysis shows that the 

majority of drivers of large trucks who die during crashes are unbelted (59 percent in 2005, for 

94 
cases in which safety belt use was known). The most frequent crash types resulting in driver 

fatality are rollover crashes and vehicle-to-vehicle collisions. In terms of driver fatality per crash 

involvement, rollover crashes were found to have the highest rate, with 2.7 percent fatalities per 

crash involvement, followed by noncollision events with a fatality rate of 0.78 percent fatalities 

per crash involvement. Noncollision events include vehicle jackknife, ejections without impacts, 

and vehicle fires. During collisions with fixed objects, 0.65 percent fatalities per crash 

involvement were found. Collisions with fixed objects include impacts with roadside features 

including narrow objects, roadside devices like guardrails, and other fixed devices. 

Overall, 83 percent of fatal crashes occur on high-speed roadways during daytime normal driving 

conditions. Detailed clinical case reviews were conducted using the LTCCS to characterize 

crashes in which belted occupants died. The analysis suggests that belted occupants were 

primarily injured during crashes where significant structural intrusion occurred. Clinical case 

reviews were conducted using the LTCCS data due to the availability of detailed damage 

information within the file and detailed information describing driver injury profiles. During the 

review, no evidence of safety-belt-induced injury was found for any cases considered. 

A subsequent review of unbelted-driver crash cases was conducted using the LTCCS database to 

determine what impact safety belt use would have had on driver injury outcomes had drivers 

buckled up. Overall, this review identified that the number of moderately to seriously injured 

drivers would have been reduced by 47 percent to 75 percent overall. This corresponds with a 

potential reduction of 1,600 to 2,500 moderately to seriously injured drivers per year. The review 

also identified that 39 percent of fatalities (in the population considered) might have been 

prevented if a traditional three-point safety belt had been worn during the crash events. This 

corresponds with the prevention of 138 driver deaths per year if all unbelted CMV drivers had 

used their safety belts. If safety belt use rates rose to the level observed for passenger vehicle 

drivers in 2006 (from 59 percent to 81 percent), a total of 74 CMV driver fatalities would be 

prevented. Similarly, if a 22-percent increase in CMV driver safety belt use rates occurred, 

approximately 860 to 1,340 moderately to seriously injured CMV drivers would have sustained 

fewer serious injuries or no injuries at all during their crashes. 

8.1. SUMMARY 

The goal of this study was to assist FMCSA in identifying promising technologies to increase 

safety belt use by CMV drivers. Each technology explored could be classified in one of three 

categories: (1) comfort strategies, (2) reminder strategies, or (3) enforcement strategies. A 

second phase of the study involved the analysis of real-world crash data from the FARS and 

LTCCS databases to identify characteristics of fatal and serious-injury crashes involving CMV 

drivers. The analysis considered common characteristics of belted and nonbelted drivers of all 

large trucks. For this study, the terms “all large trucks” and “Commercial Motor Vehicles” 

(CMVs) are used interchangeably and refer to any vehicle with a GVWR of 10,001 pounds or 

more. 

This study identified four promising technologies likely to increase safety belt use by CMV 

drivers. These are: (1) Enhanced Audible Reminder Systems, (2) Brightly Colored Safety Belts, 

(3) Safety Belt Tension Adjustors, and (4) Seat-Integrated Safety Restraint Systems. These 

95 
technologies provide audible and visual reminders for drivers to buckle up, or improve the 

comfort of existing safety belt systems to address complaints made by some drivers. 

During the study, currently available technologies were identified during a systematic review of 

technical publications and other available information sources. Discussions with industry 

stakeholders, including vehicle and restraint manufacturers, trade organization representatives, 

insurance and safety researchers, and CMV drivers, were conducted to better understand their 

perspectives on the safety-belt-use problem and to determine their opinions of each technology 

considered. The research team attended several meetings of FMCSA’s CMV Safety Belt 

Partnership to discuss the research and explore viable solutions. Many of the partnership 

members also contributed significantly during stakeholder discussions. A BCA was performed to 

estimate the potential injury and fatality cost savings likely if a fleet owner or vehicle owner 

chose to equip their vehicles with any of the devices in question. 

The study concludes that increased safety belt use would significantly reduce the number of 

seriously and fatally injured CMV drivers. The economic burden associated with these casualties 

due to nonuse of safety belts for drivers of all large trucks is estimated to be $675 million 

annually. This cost of unbelted driver injuries and fatalities is $489 million annually for Class 7 

and 8 truck drivers alone. Study results indicate that if a device increases safety belt use by at 

least 15 percent and the device cost is $273 or less per vehicle, the device is considered to be 

cost-beneficial. For Class 7 and 8 trucks alone, if the device costs less than $725 per vehicle and 

is expected to increase safety belt use by 15 percent, the system is cost-beneficial. Most of the 

technologies considered during the study were significantly less expensive than $725 and would 

therefore be cost-beneficial solutions to increase safety belt use in Class 7 and 8 trucks. If a 

device increases safety belt use as little as 5 percent, then a device that costs as much as $91 for 

all large trucks or $240 for Class 7 and 8 trucks would be cost-beneficial. 

The introduction of basic audible or visual reminder systems might positively affect safety belt 

use rates of CMV drivers; however, it was discovered that the implementation of enhanced 

audible reminder systems would likely bring about the greatest positive change. This is based on 

evidence of their successful use in passenger vehicles and on feedback from industry 

stakeholders and drivers. During this study, it was discovered that no Federal regulations exist 

that require safety belt reminder systems of any kind (audible or visual) for vehicles weighing 

10,001 pounds and more. This differs from passenger vehicle standards, where audible and 

visual reminders are required for drivers. 

The introduction of a brightly colored safety belt system is another cost-effective and promising 

approach to increase safety belt use rates by CMV drivers. A safety belt system with enhanced 

visibility allows for simplified enforcement of safety-belt-use laws and corporate safety-belt-use 

policies. Perhaps more important, the presence of a brightly colored safety belt increases the 

perceived threat of enforcement. Based on estimates performed here, enhanced audible 

reminders and brightly colored safety belts are both assumed to be cost-beneficial solutions. 

Their anticipated BCRs are 2.60 and 1.70, respectively, for all large trucks. If the BCR is greater 

than 1 for a particular device, it can be considered to be a cost-beneficial solution where the 

predicted injury cost savings due to increased safety belt use exceeds the cost required to equip 

one or more vehicles with the device. For drivers of Class 7 and 8 trucks alone, the BCRs for 

enhanced audible reminders and brightly colored safety belts are 6.90 and 4.50, respectively. 

96 
Safety belt tension adjustors, commonly known as the Komfort Latch, are widely available today 

and are designed to help CMV drivers configure safety belt systems for optimal comfort. 

However, specialized driver education in the proper use of the systems must occur in order to 

realize the greatest increase in safety-belt-wearing rates. In addition, the Komfort Latch System 

allows for the introduction of a variable amount of slack into the safety belt system to achieve a 

more comfortable fit. The introduction of slack into a safety belt is known to reduce its 

effectiveness in preventing injuries and fatalities. Seat-integrated safety restraints also offer an 

enhanced comfort solution, yet device costs exceed the likely benefit of the proposed system 

based on calculations performed here. 

Some approaches suggested here must be adopted voluntarily by vehicle manufacturers or fleet 

owners when purchasing vehicles. Others could be addressed through improvements in existing 

safety belt regulations. 

The data analysis tasks performed here identified key factors of the belted and unbelted CMV 

driver population. For both belted and unbelted drivers, the majority of CMV driver fatalities 

occurred during rollover crashes, followed by impacts with other vehicles. A review of belteddriver fatalities and serious-injury crashes indicated that virtually all involved significant damage 

to the occupant compartment. The most common crash types in which a belted driver died were 

rollovers with considerable roof or side structure damage. Impacts with fixed objects, including 

roadside objects like bridge abutments and trees, occur frequently during fatal crashes. 

Overall, increased safety belt use by drivers of large trucks would reduce the frequency and 

severity of driver injuries and fatalities. Based on a review of unbelted driver fatalities, it was 

estimated that 39 percent of fatalities (approximately 138 drivers per year) could be prevented 

with safety belt use. If safety belt use rates rose to the level observed for passenger vehicle 

drivers in 2006 (from 59 percent to 81 percent), a total of 74 CMV driver fatalities would be 

prevented. The review also suggests that 47 to 71 percent of moderately to seriously injured 

drivers (1,600 to 2,500 drivers per year) could have sustained injuries less severe if they were 

properly restrained. This corresponds to preventing moderate to severe injuries in approximately 

860 to 1,340 CMV drivers if safety belt use rates rose to the level observed in 2006 for passenger 

vehicle drivers. 

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REFERENCES 

Balci, R., Vertiz, A., and Shen, W. (2001.) Comfort and Usability of the Seatbelt (SAE Technical 

Paper No. 2001-01-0051). Washington, DC: Society of Automotive Engineers. 

Bentley, J. J., Kurrus, R., and Beuse, N. (June 2003.) Qualitative research regarding attitudes 

towards four technologies aimed at increasing safety belt use (Docket Number NHTSA–

2002–13226). Washington, DC: U.S. Department of Transportation, National Highway 

Traffic Safety Administration. 

Bergoffen, G. Knipling, R. R., Tidwell, S.A., Short, J.B., Krueger, G. P., Inderbitzen, R.E., 

Reagle, G., Murray, D.C. (2005). Commercial Truck and Bus Safety Synthesis Program, 

Synthesis 8, Commercial Motor Vehicle Driver Safety Belt Usage. Transportation Research 

Board. 

Eby, D.W., Molnar, L.J., Kostyniuk, L.P., Shope, J.T. (2005). Developing an Effective and 

Acceptable Safety Belt Reminder System. Proceedings of the Nineteenth International 

Technical Conference on the Enhanced Safety of Vehicles, Paper No. 05-0171. 

Federal Register. (1974). Federal Motor Vehicle Safety Standards: Seat Belt Warning System. 

Vol. 39, No. 236, Dec. 6, pp. 42,692–42,693. 

Fildes, B., Fitzharris, M., Koppel, S., and Vulcan, P. (2002). Benefits of Seat Belt Reminder 

Systems. Report CR 211. Monash University Accident Research Centre, Victoria, Australia, 

Dec. 

FMCSA. Report to Congress on the Large Truck Crash Causation Study, U.S. Federal Motor 

Carriers Safety Administration, Report Number MC-R/MC-RRA, 109th Cong., 2nd sess., 

March 2006. 

Hayworth, N.L., Bowland, L., Foddy, B., Elliot, B. (1996). Truck Seat Belts. Proceedings of the 

Fifteenth International Technical Conference on Enhanced Safety of Vehicles. 

Howell, W., Champion, D.A., DeLucia, P.R., Bella Dinh-Zarr, T., Finkelstein, M.M., Haseltine, 

P.W., Loeb, P.D., Reinfurt, D.W., Tanur, J.M., Viano, D.C., Williams, A.F. and Zmud, J.P. 

(2003). Special Report 278: Buckling Up: Technologies to Increase Seat Belt Use. 

Transportation Research Board, National Academies, Washington, DC. Available from 

http://onlinepubs.trb.org/onlinepubs/sr/sr278sum.pdf. 

Robertson, L. S. (1975). Safety Belt Use in Automobiles with Starter-Interlock and Buzzer-Light 

Reminder Systems. American Journal of Public Health, Vol. 65, No. 12, pp. 1319–1325. 

Simon, M.C., Botto, P., Page, P., Paulhet, F. (2001). The Potential Gain to be Achieved by 

Generalization of Seat Belts and Airbags in Trucks, The International Conference on 

Enhanced Safety of Vehicles, SAE 2001-06-0193, Amsterdam, Holland. 

Zaloshnja E., Miller T.R., Romano E.O., Spicer R.S. (2004.) Crash Costs By Body Part Injured, 

Fracture Involvement, and Threat-To-Life Severity, United States, 2000. Accident Analysis 

and Prevention 36 (3):415–427. 

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