o

US Deportment

of Transportation

National Highway

Traffic Safety

Administration

DOT HS 807 072 February 1987

NHTSA Technical Report

An Evaluation of the Bumper

Standard-As Modified in 1982

This document is available to the public from the National Technical Information Service, Springfield, Virginia 2216'
The United States Government does not endorse products

or manufacturers. Trade or manufacturers' names appear

only because they are considered essential to the object

of this report.
Technical Report Documentation Page

1. Report No.

DOT HS 807 072

2, Government Accession No. 3. Recipient's Catalog No.

4. Tit U and Subtitle

An Evaluation of the Bumper Standard - As Modified

in 1982 ••

5. Report Date

February 1987

6. Performing Orgoniiation Code

7. Author's)

Warren G. La Heist and Frank G. Ephraim

8. Performing Organization Report No.

9. Performing Organiiatlon Name and Addroti

Office of Standards Evaluation

National Highway Traffic Safety Administration

Washington, D.C. 20590

10. Work Unit No. (TRAIS)

11, Contract or Grant No.

12, Sponsoring Agency Nome and Address

Department of Transportation

National Highway Traffic Safety Administration

Washington, D.C. 20590

13. Type of Report and Period Covered

NHTSA Technical Report

4. Sponsoring Agency Code

l5. Supplementary Notes

Comprehensive evaluation of the benefits, costs and benefits to consumers of

the bumper standard as modified in 1982 compared to the previous standard.

16. Abitroct

An evaluation of the Bumper Standard was conducted to determine actual benefits and costs and

cost effectiveness of changes made (1n 49 C.F.R. Part 581) 1n 1982. These changes, effective

with the 1983 model year, reduced required damage resistance for passenger car bumpers from 5

mph longitudinal front and rear barrier and pendulum Impacts and 3 mph corner pendulum Impacts

to 2.5 and l.S respectively. The requirement that there be no damage to the bumper Itself

beyond a 3/8 Inch "dent" and 3/4 Inch "set" (or displacement) from original position was changed

to allow damage to the bumper Itself while still requiring no damage to safety-related parts and

exterior jurfacts not Involving the bumper. The evaluation was conducted under requirements of

Executive Orders 12291 and 12498.

The evaluation compares collision damage experience and bumper system costs of 1983/84 models

(post-standard modification) to a two year baseline of 1981/82 models (pre-mod1f1cat1on).

Manufacturers were selective 1n Implementing the new minimum requirements, with only 35 percent

of the cars sold In the U.S. 1n 1983 being equipped with bumpers that were changed 1n a way

which reduced collision damage resistance when compared to the predecessor 1981/82 models. By

the 1984 model year, slightly over 50 percent of models sold were equipped with bumpers changed

1n comparison to 1981/82 models.

The principal conclusions are:

(1) The costs to consumers have not changed as a result of the

modification of the bumper standard from 5 to 2.5 mph.

(2) The net effect, over a car's 10 year life, 1s a small Increase 1n

repair cost, which 1s offset by a reduction 1n the cost of the bumpers.

(3) The change 1n the bumper standard has not affected the protection

of safety-related parts.

17. Key Word.

Bumper Standard; Exterior Protection;

CFR 49 Part 581, Title I-MVICS;

Evaluation; statistical analysis;

Cost Effectiveness

18. Distribution Statement

Document is available to the public

through the National Technical

Information Serv'ce, Springfield,

Virginia 22161

19. Security Clatiif. (ol thi« report)

Unclassified

20. Security Claisif. (of thi s page)

Unclassified

21. No. of Pages

159

22. Price

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized
TABLE OF CONTENTS

PAGE

SUMMARY i x

1. INTRODUCTION AND BACKGROUND 1

1.1. Evaluation of Federal Motor Vehicle Safety

Standards 1

1.2. The Bumper Standard 2

1.3. The Evaluation of the Bumper Standard --

Apri 1 1981 4

1.4. Modification of the Bumper Standard — 1982 5

2. BUMPER DESIGN, WEIGHTS AND COSTS 9

2.1. Bumper Design Changes 10

2.1.1. Sample Selection 10

2.1.2. Model Year Compari sons 11

2.1.3. Bumper Design Classification 12

2.1.4. Design Change Classification and

Analysi s 13

2.2. Market Effects 16

2.3. Bumper System Weights and Costs 18

2.4. Bumper Weight and Cost Differences

Between Model Years 19

2.4.1. Bumper Facebar Changes 25

2.4.2. Structural Changes 26

2.4.3. Energy Absorber Changes 26

2.4.4. Structural and Energy Absorber Changes 27

2.4.5. Summary of Design Change Effects 28

3. ON-THE-ROAD COLLISION EXPERIENCE 30

3.1. Measures of Bumper Effectiveness 31

3.1.1. Damage Frequency 31

3.1.2. Extent of Damage 32

3.1.3. Bumper Override and Underride 33

3.2. Data Requirements and Sources 33

3.3. The Driver Survey 35
3.3.1. Survey Design 36

3.3.2. Collision Damage Frequency — Results of the

Dri ver Survey 37

3.3.3. Damage Repair Costs — Unreported Low Speed

Collisions 40

3.3.4. Damage to Parts in Unreported Low Speed

Collisions 44

3.3.4.1 Number of Parts Damaged 44

3.3.4.2 Severity of Damage to Parts 46

3.4. Insurance Claim Data 50

3.4.1 Description of State Farm Files 51

3.5. Analysis of Effectiveness Based on Insurance

Claim Data 53

3.5.1 The Proportion of Bumper-Related Insurance

Claims 53

3.5.2 The Average Repair Cost of Bumper Damage Based on

Insurance Claims 55

3.6. The Effect of the Type of Bumper System Changes Made

in Response to the Bumper Standard Modification 57

3.6.1. Damage Frequency by Change Category 58

3.6.2. Average Repair Cost by Change Category 62

3.7. Damaged Parts in Collisions for Which an

Insurance Claim was Filed 63

3.8. Bumper Mismatch in Unreported, Low Speed

Col 1 i sions 64

4. BENEFITS AND COSTS 67

4.1. Description of Factors Involved in the Calculation

of Lifetime Benefits and Costs 68

4.1.1. Selection of Inflation Rate 68

4.1.2. Establishment of a Base Year for Analysis 69

4.1.3. Controlling for a Changing Vehicle Size Mix 69

4.1.4. Low Speed Collisions Reported to the Police 70

iiv
4.1.5. Effect of Secondary Weight 71

4.1.6. Collision Incident Rates 72

4.1.7. Discounting Applicability and Methods 73

4.2. The Effect of the Bumper Standard Modification in

Terms of Benefi ts and Costs 76

4.2.1. Incremental Gross Discounted Lifetime

Benef 1 ts 76

4.2.2. Incremental Lifetime Costs 79

4.2.3. Net Benefits 82

4.3. Effects on Net Benefits by Type of Bumper Design

Change 85

4.3.1 Incremental Gross Lifetime Discounted Benefits by

Bumper Design Change Category 85

4.3.2. Incremental Lifetime Benefits and Costs by

Bumper Design Change 88

4.3.3. Net Benefits by Design Change Category 88

4.4. Effects of Additional Factors 91

4.4.1. Time and Inconvenience 92

4.4.2. The Cost of Insurance and Legal Fees 94

4.4.3. The Effect of Damage Not Repaired 95

4.4.4. The Effect of High Speed Collisions 99

4.4.5 Interest Savings 99

4.4.6. Combined Effect of Additional Factors on Relative

Net Benefits 101

APPENDIX A: DESCRIPTION OF BUMPER STANDARDS 103

APPENDIX B: MODELS STUDIED, SALES AND MARKET

SHARE 109

APPENDIX C: NAMEPLATES INCLUDED IN 1981 THRU 1984 COMPARISONS 110

APPENDIX D: BUMPER DESIGN CHANGE CATEGORIES BY MAKE/MODEL

IN 1983 AND IN 1984 Ill

APPENDIX E: MODEL FOR CALCULATING NET BENEFITS 112

APPENDIX F: DISCOUNT CALCULATION PROCEDURE 120

REFERENCES 123
LIST OF TABLES

Table 1-1 Summary of Bumper Standards Since 1972 3

2-1 Automobile Bumper and Curb Weights 9

2-2 Bumper a/eights, by Model Year,

Production/Sales Weighted Average 20

2-3 Bumper Costs, by Model Year, Production/Sales

Weighted Average 21

2-4 Weight and Cost Difference: 1983 vs 1901/32 22

2-5 Weight and Cost Difference: 1904 vs_ 1901/02 23

2-6 Weight and Cost Difference: 1983/04 vs 1981/82 24

3-1 Damage Frequency ~ Survey of Low Speed Collisions; Net

Difference Between Changed and Unchanged Bumper Systems:

1903 vs 1981/82 Models 38

3-2 Damage Frequency - Survey of Low Speed Collisions;

Net Difference Between Changed and Unchanged Bumper

Systems: 1934 vs 1901/82 Models 39

3-3 Damage Frequency - Survey of Low Speed Collisions; Net

Differences Between Changed and Unchanged Bumper Systems:

1903/84 vs 1981/02 Models 41

3-4 Damage Repair Costs for Unreported Low Speed Collision

Incidents in the Survey; Net Differences Between Changed

and Unchanged Bumper Systems: 1983/84 vs 1981/82

Model s 77 42

-5 Distribution of Unreported Low Speed Collisions by

Number of Damaged Parts 45

3-6 Damage Severity to Front Exterior Parts; Part Damage

by Model Year for Unchanged and Changed Bumper Systems 48

3-7 Damage Severity to Rear Exterior Parts; Part

Damage by Model Year for Unchanged and Changed

Bumper Systems 49

3-8 Proportion of Insurance Claims for Bumper Related Damage;

Net Difference Between Changed and Unchanged Bumpe,r

Systems 54

3-9 Average Damage Repair Cost for Bumper - Related Damage

Insurance Claims; Net Difference Between Changed and

Unchanged Bumper Systems 56

vl
3-10 Proportion of Insurance Claims for Bumper Related

Damage for Four Change Categories; Net Difference

Between Changed and Unchanged Bumpers Systems: 1983/84 yi

1981/82 59

3-11 Average Damage Repair Cost for Bumper Related Insurance

Claims for Four Change Categories; Net Differences Between

Changed and Unchanged Bumper Systems 1983/84 y_£

1981/82 60

3-12 Frequency of Damaged Parts in Bumper Related Insurance

Claims; Front and Rear Combined; Net Difference Between

Changed and Unchanged Bumper Systems: 1983/84 y_£

1981/82 65

3-13 Frequency of Bumper Contact in Two-Car Unreported

Collisions; Net Difference Between Changed and Unchanged

Bumper Systems: 1983/84 vs

1981/82 66

4-1 Vehicle Miles Discounted over 10 Year Life 75

4-2 Incremental Gross Lifetime Discounted Benefits;

Net Difference Between Changed and Unchanged Bumper

Systems 78

4-3 Incremental Costs, Including Lifetime Discounted Fuel

Costs; Net Difference Between Changed and Unchanged Bumper

Systems 80

4-4 Relative Net Benefits; Net Differences (Benefits less Costs)

Between Changed and Unchanged Bumper

Systems 83

4-5 Incremental Gross Lifetime Discounted Benefits

for 4 Change Categories; Net Difference Between

Changed and Unchanged Bumper Systems 86

4-6 Incremental Costs, Including Discounted Fuel Costs

for 4 Change Categories; Net Difference Between

Changed and Unchanged Bumper Systems 89

4-7 Relative Net Benefits; Net Differences (Benefits

less Costs) Between Changed and Unchanged Bumper

Systems for 4 change Categori es 90

4-8 Adjustment to Net Difference in Gross Benefits

(from Table 4-2) 97

4-9 Adjustment to Net Difference in Gross Benefits

(from Table 4-5) 98

4-10 Adjustment to Net Difference in Incremental

Costs for Interest Savings 100

4-11 Relative Net Benefits Adjusted for Additional

Factors 102

vn
SUMMARY

On April 9, 1971, the National Highway Traffic Safety Administration

(NHTSA) issued its first regulation on passenger car bumpers. Federal

Motor Vehicle Safety Standard (FMVSS) 215, "Exterior Protection," was

initially effective on September 1, 1972, and imposed requirements which

prohibited damage to specified safety-related components such as headlamps

and fuel systems in a series of perpendicular barrier impacts, at 5 mph

for front and 2.5 mph for rear bumper systems.

Under subsequent legislation and regulations, performance requirements

were changed several times. For the 1979 model year, the standard

required that there be no damage to safety-related parts and exterior

surfaces not involving the bumper system—a requirement known as Phase

I—at impact test speeds of 5 mph. The most stringent requirements were

in effect for 1980 to 1982 models, and required 5 MPH longitudinal front

and rear barrier and pendulum impacts, as well as no damage to the bumper

itself beyond a 3/8 inch "dent" and 3/4 inch "set" or displacement from

original position. These latter requirements which limited damage to the

bumper are referred to as "Phase II." The last change in the bumper

standard took place on May 14, 1982 when the requirements were modified,

reducing the test impact speeds from 5 mph to 2.5 mph for longitudinal

impacts and from 3 mph to 1.5 mph for corner pendulum impacts. The Phase

II damage requirement was dropped and replaced with the previous Phase I

requirement.
Drawing on the best available data and public comments, NHTSA completed a

Final Regulatory Impact Analysis (FRIA) in support of the final rule

amending the bumper standard to the 2.5 mph, Phase I requirement. The new

requirement became effective on July 6, 1982, affecting 1983 and

subsequent model year cars.

Executive Order 12291, dated February 17, 1981, requires Federal agencies

to perform evaluations of their existing regulations, including those

rules which result in an annual effect on the economy of $100 million or

more. The objectives of an evaluation are to determine the actual

benefits and costs of equipment, systems and devices installed in

production vehicles in connection with a regulation — and to assess cost

effectiveness. Evaluation of standards is also consistent with, and part

of, the Regulatory Program initiated under Executive Order 12498, dated

January 4, 1985.

This evaluation compares the collision damage experience and bumper system

costs of 1983 and 1984 models to a two year baseline consisting of 1981

and 1982 models which correspond to the period before the standard was

modified. An important aspect of this comparison is the fact that

manufacturers were selective in implementing the new minimum requirements

of the regulation. In 1983, for example, only 35 percent of the cars sold

in the United States were equipped with bumpers that, upon close scrutiny

and analysis, were changed in a way which reduced collision damage

resistance ••- in comparison to their 1981 and 1982 model predecessors.
In 1984, additional models were found to incorporate strength reducing

changes, and other models, whose front bumpers had been reduced in 1983,

now also were given reduced strength rear bumpers. By the 1984 model year

slightly over 50 percent of the models sold were equipped with changed

bumpers when compared to 1981 and 1982 models. Most of the changes were

made to both the front and rear bumpers of a model.

It is important to define the term "changed," since the technique used for

evaluating the effect of the bumper standard modification relies entirely

on the difference between "changed" and "unchanged" bumper systems and

comparing each of these populations to their 1981 and 1982 predecessors.

Changed bumper designs are those make/model bumpers which in 1983 and/or

1984 were reduced in strength when compared to their 1981/1982

predecessors. Reduced strength was determined on the basis of a detailed

examination of bumper designs and parts; it was not measured directly

(i.e., by impact test). Unchanged bumper designs are the make/model

bumpers which in 1983 and/or 1984 were essentially identical to their

1981/1982 predecessors. The cars with unchanged bumpers serve as the

control group in the experimental design for the evaluation.

When referring to changes, alterations to general styling, aerodynamic

flow shape and other "cosmetic" changes are excluded from the analyses and

only the energy management components — the major portion of a bumper

XI
system — are considered. Consequently, the changes found in 1983 and 1984

bumpers were categorized into four mutually exclusive groups:

o Facebar thinning or downgauging

o Structural reductions or eliminations involving mounting brackets,

reinforcements, end caps, etc.

o Energy absorber replacement with rigid brackets

o A combination of structural and energy absorber changes

The fifth category is composed of those bumpers which were left unchanged from

their 1981 and 1982 predecessors that had to meet the 5 mph, Phase II

standard. Overall, the population of cars with changed bumpers averaged a

curb weight of 2,690 lbs. in contrast to 2,920 lbs. for cars with unchanged

bumpers. There appears to have been a tendency to change bumpers on the

smaller models — subcompacts and compacts — more often than on intermediates

and standard sized passenger cars.

As has been the practice for evaluations of regulations, the analyses of

weight, cost and component identification were supported by "teardown"

methodology, a complete disassembly and analysis performed under contract, on

an average of 60 make/models for each of the four (1981 through 1984) model

years in the study. Each year this number represented at least 85 percent of

domestic production and 55 percent of Import sales, or approximately 80

percent of the combined fleets. These data form the primary basis for the

cost side in the benefit-cost analysis.

XI 1
Estimation of benefits is based on differences in both damage frequency and

repair cost between changed and unchanged systems, in 1983 and 1984, relative

to their respective 1981 and 1982 predecessors, in low-speed collisions.

To focus on low-speed, bumper-related collisions two data sets are

needed. One is obtained from a national survey of incidents not reported

to insurance companies. The other is derived from a sample of insurance

claim files screened to exclude incidents involving injuries and cases

where the vehicle had to be towed from the scene. These sources and

procedures are essentially the same as those used in the bumper evaluation

published in April 1981.

The primary conclusion of the evaluation is that after two years in which

certain design changes were made to a growing population of bumpers — in

response to a modified bumper regulation -- the road experience in terms

of low-speed bumper-related collisions for the cars with changed bumpers

has remained the same as the experience with cars equipped with bumpers

manufactured to the previous 5 mph standard.
The principal findings and conclusions of the evaluation are the following:

Principal Findings

Bumper System Weights and Costs

o Combined front and rear bumper systems that were changed — that

is reduced in strength — after the standard was modified, weighed

less than their 1981 and 1982 model predecessors. The 1983 model

bumpers weighed 72 lbs. compared to 85 lbs. for the 1981/82

models. In 1984, the average bumper that was changed, weighed 74

lbs.--a slight gain over 1983 models.

o Costs of bumpers decreased from $138 (1984 dollars) for the

1981/82 models to $114 for 1983 models. By 1984, bumper costs

went back up to $125 because more energy-absorbing materials were

added to certain bumper designs, and in some cases, aluminum was

substituted for steel in facebars.

o In 1984 more than 50 percent of the new passenger car fleet was

equipped with bumpers that incorporated a design change which

reduced the strength of the bumper.

o The dominant design change was a reduction in the number of

structural bumper parts such as reinforcements to facebars,

brackets and end caps. In 1984, one quarter of the cars produced

had bumpers with this change. They were 13 lbs. lighter and cost

$21 less than their 1981/82 model predecessors.

xiv
o Another design change was the thinning of the main bumper strength

member—the facebar. This was done on 14 percent of the 1984

passenger car fleet and resulted in a 6 lb. weight drop and a $7

cost reduction relative to 1981/1982 models.

o A combination of changes was made on 10 percent of the 1984

production fleet, including the replacement of hydraulic or

similarly actuated plunger-type bumper energy absorbers with rigid

brackets. Selected structural parts were also eliminated. The

substitution of rigid brackets for hydraulic energy absorbers

would normally result in a cost reduction and little or no change

in weight, but due to the use of more costly high impact absorbing

plastics instead of standard plastics for the fascia, prospective

cost savings were offset to yield only a net reduction of $3.

Weights of this group of bumper designs dropped by 7 lbs. due

solely to the elimination of structural parts.

o In 2 percent of the 1984 production fleet, the only design change

affecting energy management was the substitution of rigid brackets

for hydraulic energy absorbers. This group also included the use

of aluminum in place of steel for facebars or reinforcements. The

added cost of this change in material offset most of the drop in

costs for replacing the energy absorbers with brackets yielding a

net reduction of $6. A substantial weight reduction of 18 lbs.,

relative to 1981/82 predecessor models, was due entirely to the

material substitution.

xv
Collision Damage Frequency

o The 1984 and combined 1983 and 1984 changed bumper models did not

encounter a significantly different rate of damage frequency,

compared to unchanged bumper models, in low-speed unreported

collisions.

o Based on collisions for which an insurance claim was filed, there

was an increase of 6 percentage points (from 59 to 65 percent) in

the proportion of bumper-related damage claims for 1983/1984

changed bumper-equipped models. Most of the increase was

attributable to claims for rear end damage. Beyond a fairly low

impact speed, a bumper offers little or no protection. In frontal

collisions, the bumper is less of a factor in preventing damage

since these generally involve higher impact speeds than rear

collisions. Therefore, increased damage is more likely when rear

bumpers are built to a reduced standard.

Damage Repair Cost

o In unreported low-speed collisions, the average cost to repair

damage is $450. There was no significant difference in damage

repair cost between changed and unchanged 1983/1984 bumper models,

relative to their 1981/1982 predecessors, when front and rear

bumper systems are combined.

XVI
o Bumper-related damage that is severe enough for an insurance claim

costs, on the average, $1,000 to repair. This average value is

based upon reported incidents involving both changed and unchanged

bumper systems for the whole range of 1981 through 1984 models.

Repair costs of 1983/1984 changed models showed a statistically

significant reduction of $62 when compared to their 1981/1982

predecessors.

Damage to Safety and Other Parts

o In unreported low-speed collisions, there is no statistically

significant difference in the damage frequency of safety-related

and other bumper protected parts in models equipped with changed

bumpers compared to models with unchanged bumpers.

o The Insurance data revealed that parts such as lamps, radiators,

trunks and fuel tanks showed no significant change in damage

frequency in cars protected by changed bumper systems. Only hood

latches incurred a higher rate of damage in cars protected by

changed bumper systems. Past studies have shown that hood latches

rarely malfunction and when hoods fly open, they seldom cause

collisions.

x vn
Override and Underride

o The bumper standard modification did not change bumper height

requirements. The difference in bumper contact frequency of

1983/1984 changed bumper systems (86 percent) and their 1981/1982

predecessors (83 percent) is not statistically significant.

Benefits and Costs

o Collision damage repair costs dropped for both changed and

unchanged 1983/84 models, relative to their 1981/82 predecessors.

The unchanged model repair costs dropped more, but the $36

difference between these and the changed systems is not

statistically significant. The Final Regulatory Impact Analysis

(FRIA) prepared in 1982 projected a $76 increase (in 1984 dollars)

in lifetime collision damage repair cost for bumpers designed to

meet the 2.5 mph standard.

o The lifetime cost of the combined front and rear bumpers of

changed systems relative to unchanged systems dropped by $44. The

FRIA in 1982 projected a bumper system cost reduction of $91 (in

1984 dollars) for bumpers designed to meet the 2.5 mph standard.

xvin
o The net benefit of changed versus unchanged systems is $8 ($44

decrease in bumper cost minus the $36 increase in lifetime

collision damage repair), over the life of a car, but this change

is not statistically significant. There still were no significant

differences in net benefits between changed and unchanged bumper

systems even when benefits and costs were disaggregated by

facebar, structural, energy absorber and a combination of

structural and energy absorber changes. The 1982 FRIA projected

a $15 net benefit.

Time and Inconvenience

o The driver survey of low-speed, unreported collisions yielded

estimates of the average time spent in connection with incidents

involving damage, as follows:

At the scene:

Filling out forms:

Getting repair estimates:

Getting car repaired:

Time without use of car:

35 minutes

78 minutes

4 hours

1.5 days

2 days

xix
There was no difference in the amount of time expended per

Incident between cars with changed bumpers compared to cars with

unchanged bumpers. However, on a lifetime basis, given the

respective collision damage rates of changed and unchanged cars,

there is a net increase in cost of $4 for cars equipped with

changed (reduced strength) bumpers.

Conclusions

o The costs to consumers have not changed as a result of the

modification of the bumper standard from 5 to 2.5 mph.

o The net effect, over a car's 10 year life, is a small increase in

repair cost, which is offset by a reduction in the cost of the

bumpers.

o The change in the bumper standard has not affected the protection

of safety-related parts.

xx
CHAPTER 1

INTRODUCTION AND BACKGROUND

1.1 Evaluation of Federal Motor Vehicle Safety Standards

The National Traffic and Motor Vehicle Safety Act of 1966 [14]

provides the authority for issuing safety standards and specifies that

these standards be practicable, meet the needs of motor vehicle safety and

provide objective criteria. The first bumper standard issued under the

1966 Act was Federal Motor Vehicle Safety Standard (FMVSS) 215 - Exterior

Protection [4] which called for passenger cars, beginning with model year

1973, to withstand 5 mph front and 2 1/2 mph rear impacts against a

barrier without damage to certain safety-related components. Under

subsequent legislation and regulation, performance requirements were

changed several times since the first standard was promulgated. The

purpose of this evaluation is to determine the change in benefits and

costs of the latest regulatory changes which took effect on July 6, 1982,

[7] and which are applicable to passenger cars manufactured for 1983 and

subsequent model years.

Executive Order 12291, dated February 17, 1981, requires Federal

agencies to perform evaluations of their existing regulations, including

those rules which result in an annual effect on the economy of $100

million or more [5]. Evaluation of standards is also consistent with, and

part of, the Regulatory Program [8] initiated under Executive Order 12498,

dated January 4, 1985.
1 -2 The Bumper Standard

After passage of the National Traffic and Motor Vehicle Safety Act

of 1966, work began toward the development of a safety regulation for

exterior protection—the bumper standard, designated FMVSS 215. The final

rule, issued on April 9, 1971, required that passenger cars, beginning

with model year 1973, be in compliance with the standard. As shown in

Table 1-1, the standard was changed for model year 1974 by requiring

compliance with impact tests of 5 mph front and rear. This standard

remained in place through model year 1978.

In October 1972, Congress enacted the Motor Vehicle Information

and Cost Savings Act (MVICS Act) [13] which included, under Title I, the

authority to issue bumper standards which would yield the maximum

feasible reduction of costs to the public, taking into account:

o The cost of implementing the standard and the benefits

attainable as a result of implementation;

o The effect on the cost of insurance and legal fees;

o Savings in terms of consumer time and inconvenience; and

o Health and safety considerations.
The initial requirements under the MVICS Act were integrated with

FMVSS 215 and promulgated in March 1976 as a new bumper standard (49

C.F.R. Part 581) applicable to passenger cars beginning with model year

1979 and referred to as the Part 581, Phase I standard. At the same time,

a "no damage" requirement (Part 581, Phase II) was placed on bumper

systems for model year 1980 and subsequent years (see Table 1-1). The

description of Part 581 bumper standards is included in Appendix A.

TABLE 1-1

Summary of Bumper Standards

Standard

FMVSS 215

FMVSS 215

Part 581

incorporating

FMVSS 215

As above

As above

Model Year(s)

Applicable

1973

1974-1978

1979

1980-1982

1983 and

thereafter

Barrier/Pendulum Speed

and Parts Affected

5 mph front and 2 1/2 mph rear impact

with barrier. Safety-related parts only.

5 mph front and rear impacts with

barrier and pendulum; 3 mph corner

impact with pendulum. Safety-related

parts only. Pendulum test established

bumper height between 16 and 20 inches.

As above, plus no damage to exterior

surfaces, except bumper facebar and its

fasteners.

As above, except face bar can have no

permanent deviation in contour or

position greater than 3/4 inch, and no

permanent localized surface deviation

greater than 3/8 inch.

2.5 mph front and rear impacts with

barrier and pendulum; 1.5 mph corner

impact with pendulum. No damage to

safety-related parts and exterior

surfaces, except bumper facebar and

fasteners.
1•3 The Evaluation of the Bumper Standard - April 1981

The National Highway Traffic Safety Administration began to

evaluate its existing regulations in 1975—in accordance with both

Department of Transportation policies and the subsequent Executive Order

12044, dated March 1978. A bumper standard evaluation was begun in 1979

and completed, with a report published in April 1981 [10]. The evaluation

determined the net benefits (the change in costs) to the consumer

attributable to each successive standard (applicable through model year

1980) in relation to unregulated bumper systems in model year 1972 and

prior years.

The evaluation findings were that bumper systems complying with

the standard requirements for model years 1979 and 1980 (most, if not all,

bumpers were built to the 1980 "no damage" standard in 1979) tended to

show net consumer losses—based on a 10~year car life—when compared to

unregulated bumper systems. When taken separately, front bumpers were

cost effective, although yielding very small net benefits, but this was

negated by a consistent net loss for rear bumper systems through each

successive standard requirement.

Much of the history, design practice and techniques used by

manufacturers to meet the bumper standards are covered in the April 1981

evaluation report and will not be repeated here. In brief, after the

standard was first promulgated, bumpers became heavier and extended away

from the car body. Redesign during the mid to late seventies, as part of

the downsizing programs, reduced bumper weights and manufacturers often
replaced exposed facebars with elastomeric covered steel or aluminum

extrusions to meet the 1980, Phase II requirements.

While the costs of 1979/1980 systems were lower than those in 1974

through 1978, they were between $150 to $200 higher than unregulated

bumpers (1972 and earlier model years).

A review of all NHTSA regulations in 1981 took cognizance of the

1981 bumper evaluation findings in light of the criterion in the MVICS Act

which stipulated that bumper standards yield the maximum feasible

reduction of costs to the public.

1.4 Modification of the Bumper Standard - 1982

In 1981, the agency began rulemaking proceedings which included a

Notice of Proposed Rulemaking [6], accompanied by a Preliminary Regulatory

Impact Analysis [16], which outlined a series of bumper system impact test

alternatives, and scheduled public hearings. Based on testimony, docket

submissions and extensive agency analysis, a Final Regulatory Impact

Analysis (FRIA, May 1982) [9] was prepared in support of the final rule

amending the bumper standard by reducing the test impact speeds from 5 mph

to 2.5 mph for longitudinal front and rear barrier and pendulum impacts.

Phase I damage resistance criteria were substituted for Phase II
criteria. The final rule [7] was issued on May 14, 1982, and became

effective on July 6, 1982, thereby affecting 1983 and subsequent model

year passenger cars.

The discussion in the final rule summary included a statement that

"(I)nnovation, variety and a range of implemented choices in the

marketplace will permit the agency to monitor cost and benefit trends and

collect data about different performance levels of bumpers in the

future." This evaluation addresses these trends through a series of

analyses designed to establish the change in net benefits between bumper

systems manufactured in response to the 2.5 mph standard and those

manufactured under the previous 5 mph standard.

How does this objective contribute to the quest for the maximum

feasible reduction In costs to the public? A "maximum feasible reduction"

suggests that there is an optimum impact speed at which, theoretically,

such a cost reduction would occur. This impact speed will differ from

model to model, and for the aggregate model year fleet would depend on how

many cars of a particular make are sold. Moreover, manufacturers have the

choice of bumper design, limited only by a minimum performance standard.

As will be shown in subsequent chapters, lowering impact test requirements

from 5 mph to 2 1/2 mph did not, at least through model year 1904, result

in bumper system changes for all of the passenger car fleet.
It should be clear at the outset that modification of the bumper

standard only allows an iteration toward the Congressionally mandated goal

of a "maximum feasible reduction in costs to the public" on the basis of

on-the-road collision experience with bumpers, some changed, others

unchanged as a result of a modified standard. The first determination

must, therefore, be the discovery of which post-standard modification

models (the evaluation is based on 1983 and 1984 models) were

changed—considering factors such as weight reduction, down-gauging

(reducing the thickness of main structural parts such as facebars), parts

elimination or substitution.

The analysis of net benefit changes between bumpers built under

the modified (2 1/2 mph) standard and their counterparts built under the 5

mph standard can yield three outcomes. A positive (net benefit) result

would tend toward the goal of "maximum feasible cost reduction." A

negative result (net loss) would mean the opposite. The third possibility

is where no significant change is found or where the change is so small

that more on-the-road data are needed to establish the significance of the

result.

The analytic procedures and methods closely parallel those used in

the first bumper evaluation (April 1981). The evaluation design differs

since the first evaluation determined the effect of successive standards,

each with more stringent minimum requirements than the one before,
although manufacturers were free to design bumper systems to any impact

test level above the minimum. During that period, it was evident that

bumper systems were strengthened in most cases. The evaluation design,

therefore, compared respective model year fleets without disaggregation by

design within that fleet. The evaluation of the effect of the modified (2

1/2 mph) standard separates the effects of bumpers that have been changed

(reduced) from those that were not changed—and thus likely to have

continued to meet the previous 5 mph, Phase II requirements.

The following chapters deal with the evaluation design, bumper

weights and costs, the incidence, frequency and damage repair costs of

bumper-related collisions, the sources and use of data sets, the analysis,

and results in terms of any change in effectiveness, net benefits and

costs that emerged from the bumper standard modification that took effect

on July 6, 1982.
CHAPTER 2

BUMPER DESIGN, WEIGHTS AND COSTS

During the past decade the design of bumpers has undergone

significant change brought about by the need to conserve energy and reduce

the risk of low speed collision damage, while at the same time making

bumper systems as cost effective as possible. Bumper weights have

declined since 1978 as the effect of downsizing began to take hold. The

"weighted average" curb weight of the 1984 model fleet was 2780 lbs. in

contrast to 3768 lbs. for the 1973 model fleet. To reduce bumper weight,

materials such as aluminum, elastomerics and hard plastics are being

used. Table 2-1 illustrates, in the aggregate, the relative bumper and

curb weights. With the modification of the bumper standard for 1983 and

subsequent model years, bumper designs were changed in several model lines

in 1983 and additional models in 1984, but a sizable portion of both

domestic and imported fleets retained their pre-standard modification

(1981/82 model) designs.

Model

Year

1972

1973

1974

1979

1980

1981

1982

1983

1984

TABLE 2-1

AUTOMOBILE BUMPER AND

Standard

Unregulated

5/2.5

5/5

5/5, Phase I

5/5, Phase II

5/5, Phase II

5/5, Phase II

2.5/2.5, Phase I

2.5/2.5, Phase I

Bumper

Weiqhts (lbs.)

79

126

150

118

114

89

85

82

80

CURB WEIGHTS

Curb

Weiaht (lbs.)

3599

3768

3672

3180

2867

2863

2694

2778

2780

Ratio of Bumper

to Curb Weioht

.022

. .033

•- .041

.037

.040

.031

.032

.030

.029
2.1 Bumper Design Changes

In the 1983 model year, 35 percent of the fleet had bumpers which

were changed in apparent response to the modified bumper standard. In

1984, this figure rose to 51 percent. The term "changed" in this context

means that the energy management components of the bumper system were

reduced by either eliminating parts, substituting components, and/or

reducing the size and weight of strength members.

2.1.1

To identify changes, and to establish weights and costs of bumper

systems, a sample of 1981 through 1984 model bumpers were analyzed in

detail using the "teardown" method [11], [12]. The 1981 model year

passenger car sample consists of 51 nameplates, 39 of which are identical

to the 1982 models and 12 which are different. Of the total, 39 are

domestic and 12 are imports. For 1982, 56 sets of front and rear bumpers

were analyzed (44 domestic and 12 imports). The 1983 model sample totals

58 nameplates (46 domestic, 12 imports), and the 1984 sample includes 62

nameplates of which 50 are domestic and 12 are imports. Each model year

sample represents at least 85 percent of the domestic production and 55

percent of the import sales.

Both the domestic and import samples were constructed by starting

with the highest sales volume nameplate and adding subsequent models in

descending order to reach the 85 and 55 percent sales volumes. In

assembling each model year sample several factors were considered to

assur e—t o the degree possible—that the same nameplates appear for each

model years' list. In addition, the sample was designed to represent each

10
major manufacturer, market class (vehicle size), design and major bumper

material content. Information obtained by the agency from major

manufacturers describing bumper design changes made to 1983 and 1984

models was also used for sample selection.

The final lists of models studied together with their sales

volume and market shares are shown in Appendix B.

2.1.2 Model Year Comparisons

Most models in each of the 4 model year samples retained their

nameplates over the 4 model years so that 1983 or 1984 models could be

compared with their 1981 and/or 1982 predecessors to determine changes in

weight and cost. For example, the Ford Mustang was manufactured in 1981,

1982, 1983, and 1984 and for each model year, ranked sufficiently high in

sales volume to be included in the respective model year samples. Some

make/model nameplates changed only slightly, such as the 1982 Mercury

Grand Marquis which was replaced with a new model in the same market

class. Others, such as the Datsun 210 served as an equivalent predecessor

to its replacement, the Nissan Sentra.

In 1983 and in 1984, several new nameplates, without equivalent

predecessors, were introduced by manufacturers, such as the Ford Tempo and

Topaz models in 1984, at about the time Ford discontinued the Fairmont. A

few models were not included in the 1983 or 1984 samples because their

market shares shrank considerably, e.g., the Pontiac Phoenix and

Bonneville.
The nameplates that are included in the 1981 through 1984

comparisons are shown in Appendix C.

2.1.3 Bumper Design Classification

The front and rear of a passenger car design includes both

integrated and component bumper systems. Many front bumpers are covered

with a one-piece plastic fascia material that includes the grille, bumper

facebar or reinforcement cover, and the valence panel. Turn signals

and/or side-marker lamps can also be integrated with the bumper system.

In the teardown analysis, bumper system parts were classified into two

groups: energy management and cosmetic (and the total of both). Where

possible, however, parts of bumper systems not related to energy

management were excluded from the study. For example, the Ford Mustang

fascia has a clear line between the grille and the front bumper

reinforcement cover. The grille was cut off the fascia at that line

before the fascia was weighed and its consumer cost was estimated. In

other instances, parts could not be separated because they were clearly

integral to the assembled bumper system even though they served no

energy-management function. Optional parts that are not necessary in

order to comply with the standard—based on manufacturer information—were

included with the "cosmetic" group. Thus bumper guards were classified as

energy management if they were part of the basic vehicle bumper system,

but were classified as cosmetic if they were optional equipment added on

later to meet market demand.

12
The data sets for each system are, as shown in the contractor

reports, identified as "Total", "Energy Management" and "Cosmetic." It is

the energy management portion which will be the focal point of the

analysis.

2.1.4 Design Change Classification and Analysis

Changes in energy management bumper parts were classified into 5

groups (a no-change group plus 4 levels of change). To determine if and

what changes were made to 1983 and 1984 model bumper systems, each of the

systems were compared to their 1982 model counterparts or "predecessors."

Each change fits only into one group for a given make/model comparison. A

given make/model may, for instance, have no change, or a different type

change in either the front or rear bumper system (this was found in 10

percent of the 83 to 82 and 84 to 82 comparisons). Combinations of change

groups can likewise be compared.

The definition of each design change classification is based on

judgments of its effect on energy management. For example, changes in

facebar thickness and changes from hydraulic energy absorbers to stamped

brackets are likely to decrease the energy absorption capability of bumper

systems. The classifications are ranked from the least to the most effect

on energy management.

No change - All energy management parts of 1983 and 1984 model

bumper systems when compared to their corresponding

1982 model bumper system parts are essentially

unchanged. Bumper systems with minor changes in

fascia design were included in this "no change" group

if the first criterion was met.

n
Facebar change - Bumper system parts designated as "facebars" for

exposed bumper systems, or "reinforcement" for

bumper systems covered with pliable plastic or

rubber fascia material were compared to parent 1982

parts to determine changes in the gauge or the

amount of material when the overall bumper

dimensions (length, height, offset) remained

unchanged. If other changes were minor such as

removal of shims or attaching parts (bolts, nuts,

washers) along with facebar changes, the bumper

systems were included in this classification. Not

included as a facebar change is the substitution or

replacement of one material for another, such as

changes from steel to aluminum or high strength

steel to galvanized steel.

Without a detailed design analysis, it would not be

possible to determine if the material change resulted in

a change in energy management capability.

Structural Changes - When several 1983 and 1984 model bumper systems were

compared with their corresponding 1981 and/or 1982 model

bumper systems, and the facebar and energy absorbers

were unchanged, but other parts such as mounting

brackets, end caps, nerf strips, reinforcements (behind

the primary facebar or reinforcement) were reduced in

size or eliminated entirely. These design differences

were classified as structural changes.
Energy Absorber - For several 1983 and 1984 model bumper systems, the

Changes

only energy management design change made, compared

to their corresponding 1982 model bumper systems was

to replace the hydraulic energy absorber with a

stamped rigid assembly or bracket or with a rubber

block. Since this type of change would result in

potentially less energy absorption capability as

well as more crash energy being transmitted directly

to the bumper system itself, this classification was

considered a greater reduction in energy management

than either facebar or structural change.

Energy Absorber - In addition to changing the energy absorber to a

+ Structural

Change rigid bracket, some 1983 and 1984 model bumper

systems when compared to their 1982 model systems

included structural changes as previously defined.

This classification is assumed to result in bumper

systems with less energy management capability than

any of the aforementioned categories.

Bumper design change classifications by make/model for 1983

compared to 1982/1981 and for 1984 compared to 1982/1981 are shown in

Appendix D.
As already mentioned, the aggregate of bumper models in each of

the 5 groups, for both the 1983 and 1984 model year, were compared to

their predecessors in model years 1981 and or 1982. When a new nameplate

was introduced, such as the Tempo/Topaz in 1984, where no 1981 or 1982

predecessor was available, the new bumper systems were first analyzed to

determine what components it contained and to what degree these differed

from typical 1982 installations. For example, the Ford Tempo has a bumper

system similar to other unchanged 5 mph bumpers, that is, it has energy

absorbers and equivalent facebar structures. Therefore, the Tempo bumpers

were included in the "unchanged" 1984 group which also included the Datsun

2OOSX, Mazda GLC, Ford Escort, Oldsmobile Cutlass Supreme, Buick Skylark,

etc. The sales weighted average weight and cost of this group became the

"dummy" weight and cost values of an equivalent 1982 model Tempo and Topaz

(e.g., 248,202 Ford Tempos were sold in 1984 and this volume was applied

to both the 1982 and 1984 weights and costs for the Tempo).

2.2

Because passenger cars of equal size, except for luxury and

specialty cars, have similar sales prices, their size categories are

called market classes. Passenger car size is expressed several ways:

curb weight, wheel base (length), and interior passenger and luggage

compartment volumes. The energy crises of the 1970's resulted in a shift

toward smaller vehicle dimensions for all market classes. In addition,

passenger car sale trends changed and more smaller cars were purchased

than larger cars. However, during the 1980's and especially during 1983

and 1984, the public reverted to buying somewhat larger cars again.

16
Bumper system designs, material, weight and cost are generally

similar in a market class. If the distribution of cars in each market

class does not change appreciably from year to year, each model year's

sales weighted average bumper weight and cost can be compared from year to

year to determine differences. In other words, if consumer buying

preferences do not change from year to year, the sales weighted average

bumper system weights and costs will not only reflect the respective model

year fleet data but can be directly compared to determine true

differences. The bumper data comparisons shown in the contractor final

report [11] are based on averages weighted using the respective model year

sales volumes and the differences reflect both changes in design and sales

distribution due to market shifts. Therefore, those figures were not used

as provided in the contractdr report to avoid biasing data, as explained

below.

If, for example, there 1s an upward shift toward larger cars from

one year to the next, the average bumper weights and costs for the most

recent year will reflect this. To remove any potential market effect,

sales volumes among models from one model year to the next should be held

constant. The 1984 model year was selected as the basic year and its

sales volume distribution was applied to the other model years to

establish comparative weight and cost differences between model years.

The analysis and tables that follow address straight differences

in bumper system weight and cost for the respective years. The costs are

consumer costs expressed in 1984 dollars. Consumer cost is developed from

manufacturing costs by mark-ups to account for burden and dealer profit.

Manufacturing cost is estimated from an assumed full vehicle production

17
process. Hence consumer costs are not to be confused with replacement

part costs that one would pay a dealer to obtain parts. Details of the

costing methodology are contained in the contractor's final report.

In a subsequent chapter, where the net changes in benefits are

computed, the bumper weights and costs will be converted to lifetime net

discounted costs, including secondary weight considerations and fuel costs,

2.3 Bumper System Heights and Costs

In this section, bumper weights, costs and model year differences

are presented in a series of tables. Given the large number of

disaggregations possible (nearly 500), it is best to begin with the model

years that will be used not only for determining weight and cost changes,

but will also align with collision frequency, damage incidence and repair

cost data that will be part of net benefit calculations later on. The

model year sets to be compared are as follows;

1983 vi 1981 + 1982

1984 vs 1981 + 1982

1983 + 1984 yi 1981 + 1982

Each set will be subdivided into Front plus Rear, Front only and

Rear only bumper systems. The total, and energy management only portion

will be shown for each of the three sets. As explained earlier, weight

and cost values are also grouped by "change category", of which there are

six namely: Unchanged bumper systems, Facebar, Structural, Energy

Absorber, Structural plus Energy Absorber and All Design Changes (the

aggregate of the last four).
Table 2-2 shows bumper weights by model year (1981 through

1984). These are U.S production/import sales weighted values based on the

1984 model year market distribution. Bumper costs are shown in Table 2-3.

These two tables constitute the basic weight and cost data set,

but one aspect has to be explained to clarify what the values represent.

As the notes on each table state, the columns for both 1981 and 1982

models list the weights and costs for both 1983 and 1984 successor models,

respectively. This is because in each post-standard modification model

year (1983 and 1984) the make/models that were changed are different. In

1983, changes were made to Chrysler, Honda and several GM models. In

1984, changes were extended to more nameplates, and in both years there

were cases where only the front or rear of a model was changed or the rear

bumper was changed in 1983 followed by the front bumper in 1984, and vice

versa.

2.4 Bumper Height and Cost Differences Between Model Years

Each of the three pre/post-standard modification comparisons are

presented in Tables 2-4 through 2-6. Weight and cost differences are

shown only for the energy management portion of bumper systems.

19
TABLE 2-2

BUMPER WEIGHTS BY MODEL YEAR

Production/Sales Weighted Averages

(Weight in lbs.)

o

1981

Predecessor Year 1/

Unchanged Bumpers 2/

Total 3/

Energy Kgt.

Changed Bumpers 2/

Facebar

Total

Energy Hgt.

Structural

Total

Energy Hgt.

Energy Absorber

Total

Energy Hgt.

Struct.+ Energy Abs

Total

Energy Mgt.

All Changes Combined

Total

Energy Mgt.

Front

+ Rear

1983

97

90

92

86

114

108

104

100

.4/

62

57

94

89

1984

95

89

89

83

107

101

96

SI

62

58

93

87

Front

1983

48

45

46

41

57

53

56

52

30

28

47

44

198

48

44

40

36

55

51

49

45

30

28

46

43

Rear

1983

43

45

46

45

56

54

49

48

32

29

47

45

1984

47

45

49

47

52

50

47

46

31

29

47

45

Front

+ Rear

1983

95

88

82

76

104

98

104

100

60

54

87

81

1984

93

87

83

77

102

95

97

91

60

55

89

83

1932

Front

1983

47

43

43

38

49

45

5S

52

30

27

43

39

1984

46

42

38

34

51

47

43

45

30

28

44

40

Rear

1983 1

48

45

39

38

55

53

49

48

31

27

44

42

1/ The 1983 and 1984 model years have differenc models in each design

category, thus both 1981 and 1982 models ara grouped in the same manner.

2/ See Section 2.1.4 for design definitions.

3/ See Section 2.1.3 for definitions of total and energy management.

4/ Design change included both structural and energy absorber changes.

1984

47

45

45

42

51

49

48

46

30

27

46

43

Front

+ Rear

95

88

77

70

94

89

77

74

51

45

78

72

1983

Front

47

43

41

36

45

41

46

44

25

22

39

35

Rear

48

45

36

34

50

47

31

30

26

22

39

36

Front

+ Rear

93

87

81

74

91

85

78

73

52

49

80

74

1954

Front

45

42

38

34

46

42

47

44

25

24

40

36

Rear

47

45

43

40

45

43

31

30

27

25

41

38
TABLE 2-3

BUMPER COSTS BY MODEL YEAR

Production/Sales Weighted Averages

(1984 Dollars)

Predecessor Year 1/

Unchanged Bumpers 2/

Total 3/

Energy Mgt.

Changed Bumpers

Facebar

Total

Energy Mgt.

Structural

Total

Energy Mgt.

Energy Absorber

Total

Energy Mgt.

Struct.+ Energy Abs.4/

Total

Energy Mgt.

All Changes Combined

Total

Energy Mgt.

1/ The 1983 and 1984 model years have different models in each design

category, thus both 1981 and 1982,raodels are grouped in the same manner.

2/ See Section 2.1.4 for design definition for design definitions.

3/ See Section 2.1.3 for definitions of total and energy management.

4/ Design change included both structural and energy absorber changes.

Front

+ Rear

1983

168

150

138

126

179

161

162

149

4/

133

122

156

141

1984

169

154

152

132

170

151

159

141

134

123

158

140

1981

Front

1983

87

77

67

58

93

83

84

75

66

61

79

70

1984

89

80

75

61

89

78

81

70

66

61

81

70

Rear

1983

81

73

71

68

86

78

78

74

67

61

77

71

1984

80

74

77

71

81

73

78

71

68

62

77

70

Front

+ Rear

1983

170

150

135

122

172

154

162

149

124

109

149

134

1984

167

152

154

131

166

147

160

141

125

111

155

136

1982

Front

1983 1

88

77

70

61

86

76

84

75

62

55

76

67

87

78

77

63

85

74

82

70

62

56

79

68

Rear

1983

82

73

65

61

86

78

78

74

62

54

73

67

1984

SO

74

77

68

81

73

78

71

63

55

76

68

Front+

Rear

169

150

130

107

156

134

145

136

102

87

133

114

1983

Front

87

77

71

54

78

66

79

73

50

43

68

57

Rear

82

73

59

53

78

68

66

63

52

44

65

57

Front+

Rear

168

153

151

125

149

128

147

136

124

112

145

125

1984

Front Rear

88

79

77

60

78

66

82

75

59

54

74

63

80

74

74

65

71

62

65

61

65

58

71

62
TABLE 2-4

BUMPER WEIGHT AND COST DIFFERENCES 1/

1983 vs. 1981 and 1982

(Weight in lbs., 1984 Dollars)

Unchanged Bumpers 2/

Weight

Cost

Production/sales (000

% of fleet

3/

Front

+ Rear

-1

0

6730

65

Front

-1

0

Rear

0

0

Changed Bumpers

Facebars

Weight

Cost

Production/sales (000)

% of fleet

-11

-17

828

-4

-6 -11

Structural

Weight

Cost

Production/sales (000)

% of fleet

Energy Absorber

Weight

Cost

Production/sales (000)

% of fleet

Structural and Energy Absorber

Weight

Cost

Production/sales (000)

% of fleet

All. Changes Combined

weight

Cost

Production/sales (000)

% of fleet

-14

-24

1553

15

-27

-14

311

3

-11

-30

932

9

-13

-23

3624

35

-8

-14

_2

—5

-16

-6

-11

-C

-10

-18

-12

-6

-14

-7

-12

1/ Differences are between the energy management portion of bumper

systems as defined in Section 2.1.3.

2/ See Section 2.1.4 for design definitions.

3/ Base Year is 1984.

22
TABLE 2-5

BUMPER WEIGHT AND COST DIFFERENCES

1984 vs. 1981 and 1982

(Weight in lbs., 1984 Dollars)

1/

Unchanged Bumpers 2/

Weight

Cost

Production/sales (000)

% of fleet

Changed Bumpers 2/

Facebars

Weight

Cost

Production/sales (000)

% of fleet

Structural

Weight

Cost

Production/sales (000)

% of fleet

Energy Absorber

Weight

cost

Production/sales (000)

% of fleet

Structural and Energy Absorber

Weight

Cost

Production/sales (000)

% of fleet

All changes Combined

Weight

Cost

Production/sales (000)

% of fleet

Front

+ Rear

-1

2

5073

49

Front

-1

1

Rear

0

1

-6

-7

1449

14

-13

-21

2588

25

-18

-6

207

2

_7

-3

1035

10

-11

-13

5280

51

-2

-2

-7

-10

-2

5

-4

-4

_5

-6

-4

-5

-6

-11

-16

-11

-3

1

-6

-7

1/ Differences are between the energy management portion of bumper

systems as defined in Section 2.1.3.

2/ See Section 2.1.4 for design definitions.

23
TABLE 2-6

BUMPER WEIGHT AND COST DIFFERENCES

1983 + 1984 vs. 1981 and 1982

(Weight in lbs., 1984 Dollars)

1/

Unchanged Bumpers 2/

Weight

Cost

Production/sales (000)

% of fleet

Front

+ Rear

—1

0

5798

56

Front

-1

0

Rear

0

0

changed Bumpers 2/

Facebars

WeightCost

Production/sales (000)

% of fleet

Structural

WeightCost

Production/sales (000)

% of fleet

Energy Absorber

Weight

Cost

Production/sales (000)

% of fleet

Structural and Energy Absorber

Weight

Cost

Production/sales (000)

% of fleet

Ail Changes Combined

Weight

Cost

Production/sales (000)

% of fleet

-8

-10

1139

11

-14

-22

2071

20

-23

-10

311

3

-9

-16

1035

10

-12

-17

4555

44

-3

— 3

-7

-11

-6

1

-5

~9

-6

-8

-5

-7

-7

-11

-17

-11

-4

-7

-6

—9

1/ Differences are between the energy management portion of bumper

systems as defined in Section 2.1.3.

2/ See Section 2.1.4 for design definitions.

24
The weight and cost of bumper systems that had not changed in the

1983 and 1984 model years, those that presumably retained at least a 5 mph

impact capability, show very little difference—a pound or less and two

dollars or less—when compared to their predecessor 1981 and 1982 models.

This largely confirms judgments about whether or not a particular bumper

system underwent a strength reduction change after the 2.5 mph bumper

standard went into effect.

The unchanged systems, representing 65 percent of the 1983 models

and 49 percent of the 1984 models, are used as the control group, against

which the effect of changed bumpers will be measured.

2.4.1 Bumper Facebar Changes

Thinning or using less material in the main load-bearing bumper

components—the facebar or reinforcement behind the fascia—was probably

done in response to the change from the Phase II no-damage bumper

requirement to Phase I (Phase II which applied to 1980 through 1982 models

required that test damage be held to a 3/8 inch diameter dent on the

bumper and a 3/4 inch set back from the original outer bumper contour).

In the samples, seven 1983 models and twelve 1984 models incorporated

"thinned" facebars, representing 8 and 14 percent, respectively of the

fleet. The weight reduction ranged from 6 to 11 pounds per system and the

cost dropped by between 7 and 17 dollars.

The facebar change was found principally on General Motors cars

such as the 1984 Buick Regal and Electra, the Olds Omega, the Chevrolet

Celebrity and Chevette.

25
2.4.2 Structural Changes

Structural changes are defined as a size reduction or elimination

of bumper system parts such as support brackets, and caps, nerf strips and

reinforcements behind the primary energy management facebar or fascia

covered structure. It is a specific change category which does not

include facebar changes, described previously (in Section 2.1.4), nor

energy absorber changes covered in the next category.

About 15 percent of the 1983 model bumpers had structural changes

when compared to predecessor 1981 and 1982 models. This increased to 25

percent in !984. The changes amounted to a weight reduction of 14 pounds

and a drop in costs between $20 and $24.

Structural changes to bumper systems were made by several

manufacturers for a number of their carlines, and included GM, Ford,

Toyota, Nissan, Volvo and BMH.

2.4.3

The removal of energy absorbers 1s perhaps the leading basis for

reciassifying bumpers from Phase II to Phase I and the most likely design

change expected after the modified bumper standard went into effect. So

far, at least, no industry-wide absorber eliminations have taken place.

This category and the next account for 13 percent of the fleet through

1984. Some imported and domestic models had adopted elastomeric

absorption materials even before the standard changed (and met 5/5 Phase

II compliance test requirements).

26
The change from plunger type energy absorbers to rigid brackets,

without any other change, was only found in certain Chrysler products,

based on the samples that were torn down. At between 2 and 3 percent of

the new fleet, this category is very small, particularly when sampled for

collision data.

2.4.4 Structural and Energy Absorber Changes

About 10 percent of the 1983 and 1984 sales volume included cars

with bumpers having both structural and energy absorber changes. All

vehicles in this category are either subcompacts or compacts manufactured

by Honda and Chrysler. The design changes, especially for some of the

1983 sample, reflect the greatest potential change in the bumper energy

management capability.

After a decline in 1983 models, costs for the 1984 models

increased substantially in the representative sample, largely due to

Honda's bumper change on their 1984 Accord and Civic models. The bumper

weight increased by 5 lbs. on the Civic and 8 lbs. on the Accord (sales of

147,000 and 131,000, respectively). The Accord bumper system cost $48 in

1983 and $91 in 1984. The Civic system jumped from $39 in 1983 to $76 in

1984. Most of the cost increase went into energy management rather than

the cosmetic portion of the bumper systems. The Civic fascia, apparently

a new plastic material, doubled in cost and the rubber block that serves

as an energy absorber cost $3 in 1983 and $10 in 1984.
Overall, the sample fleet incorporating a combination structural

and energy absorber change for 1984, represented slightly over 1 million

cars, and showed a 50 lb. increase in curb weight over its predecessor

sample for 1983. For example, Chrysler Reliant/Aries models which

included a combination structural and energy absorber change went from a

2323 lb. curb weight in 1983 to 2372 in 1984. The Honda Accord's curb

weight increased by 98 lbs. in the same period.

2.4.5 Summary of Design Change Effects

The sum of all design change categories (facebar, structural,

energy absorber, structural plus energy absorber) are shown below, using

1983 and 1984 yj. the 1981/82 baseline years. To highlight the aggregate

effect of the changed bumper systems, they are compared to the unchanged

systems.

Weight and Cost Differences

1983 Jiii 1981/82

Unchanged Bumper Systems

Bumper Systems with Design Changes

Wt. (lbs.) Cost ($) Ht. (lbs.) Cost_(l).

Total System

Energy Mgmt. -1 0 -13 -23

The net differences between systems that were changed and those

that were not is 12 lbs. and $23 for the energy management portion of the

bumper system.

28
Weight and Cost Differences

1984 vs^ 1981/82

Unchanged Bumper Systems

Bumper Systems with Design Changes

Wt. (lbs.) Cost ($) Wt. (lbs) Cost ($)

Total System

Energy Mgmt. -1 -1 -10 -13

By 1984, some weight had been put back on bumper systems (about 3

lbs.) and the weighted average cost had risen $8 relative to the 1983

model bumpers. One factor was the "Honda effect" discussed earlier, where

the manufacturer incorporated costlier parts in their 1984 system in

contrast to the 1983 bumpers which had been reduced in weight and cost

after the change in the bumper standard.

Given that 1981/82 bumpers weighed 85 lbs. the change in the

standard, from 5 to 2 1/2 mph, by 1984 has resulted in a weight drop of

approximately 12 percent (10 lbs.) for those bumper systems that were, in

fact, changed from their 1981/82 predecessors.

The actual cost effect—a $13 basic drop by 1984—will be covered

in more detail in a subsequent chapter which will take into account fuel

consumption and secondary weight reductions.

29
CHAPTER 3

ON-THE-ROAD COLLISION EXPERIENCE

The main purpose of bumpers, in compliance with the standard, is

to minimize damage in low speed collisions. The actual speed can, at

best, only be estimated since drivers are not likely to be looking at

their speedometer at the instant of collision. Moreover, speedometers are

not very accurate - particularly at low speeds. This accuracy range is

generally within + 4 mph, which obviously negates any precision in the

collision cases of interest. In a low speed collision there is often

little or no damage, and few if any injuries. The amount of damage and

degree of injury is used as a surrogate measure of collision speed in

accident reconstruction, but clearly this approach is applicable only to

more severe collisions in contrast to those for which a bumper is designed

to be effective in preventing, by its energy management capability,

relatively light (and repairable) damage. When the collision speed

exceeds a certain threshold, bumpers are not physically capable of

absorbing all the impact energy and the vehicle frame or other main body

structure or system is damaged. When this happens the car usually cannot

be driven from the scene of the accident.

30
In identifying a low speed, or light, collision - involving the

bumper - incidents with injuries and/or vehicles that had to be towed from

the scene should be screened out.

Another factor in a low speed collision is that it may not be

reported, either to the police, or for insurance claim purposes, and thus

no record exists. Police reports are only required when damage exceeds a

certain dollar amount (and the amounts vary from State to State) or when

persons are injured. When damage is below a driver's deductible for

collision insurance (typically $100), an insurance claim may not be

filed. Unreported cases are, however, an Important data need, and the

method used to obtain such data will be described later in this chapter.

3.1 Measures of Bumper Effectiveness

The evaluation of bumper effectiveness measures the changes in

damage sustained by cars meeting the 2.5 mph as compared with those

meeting the 5 mph bumper standard. There are two quantities which measure

effectiveness, one is the damage frequency and the other the extent of

damage.

3.1.1 Damage Frequency

The probability or frequency of damage in a low speed collision

is defined as the ratio of the number of low speed bumper-involved

accidents in which damage occurred, to the total number of low-speed

31
collisions. Assuming a similar distribution with respect to impact speed

for both pre- and post-standard cars, the change in damage frequency will

reflect the degree to which effectiveness of exterior protection has

changed on cars built to the modified (2.5 mph) standard.

3.1.2

There are several ways to measure the change in the extent of

damage in low-speed collisions: The numbers of damaged parts, the number

of damaged parts by degree of damage, and the cost to repair the damage.

The "number of damaged parts" measurement is a simple count of how many

bumper and safety-related parts were damaged. This does not, however,

reflect the considerable variation in damage severity which is possible

for any given part. A qualitative assessment of severity can be made by

classifying damage as major or minor and whether the damage can be

repaired or the part has to be replaced. This is an improvement over a

simple parts count, but still falls short because it is difficult to use

in making comparisons between benefits and costs of a standard since it

can only indicate shifts in damage severity for individual parts.

Measuring the cost to repair damage eliminates many of the

problems of the damaged part counts. It is a single value reflecting

collision severity, and allows comparisons (changes) in effectiveness

between pre~ and post-standard modification bumper systems to be made.

3?
3.1.3 Bumper Override and Underride

Another measure of effectiveness is bumper mismatch

frequency—determining whether regulating bumper height leads to damage

reduction. Uniform heights should allow bumpers to meet head-on, avoiding

potential damage caused by over or underride. Both mismatch and match

frequencies of 1981 through 1984 models together with their respective

damage, will be compared to provide a measure of uniform height

effectiveness.

3.2 Data Requirements and Sources

The evaluation design calls for data on four model years: 1981

through 1984. Specific data requirements are:

o The number of low speed, bumper-involved collisions

o The number of collisions when damage has occurred, and

the extent of the damage in terms of,

- the number of parts damaged,

- the severity of damage to each part,

- repair cost estimates (and/or replacement cost).

o In a two-vehicle collision, whether bumpers made direct

(head on) contact, or if one bumper overrode the other.

The report on the evaluation of the bumper standard published in

April 1981 [10] covered, in some detail, a series of potential data

sources including police accident reports, repair shop records, etc.
After a review and discussion of the data, the report came to the

conclusion that the most promising methods/sources were a national sample

of drivers, obtained by survey, whose bumper-involved low-speed collisions

went otherwise unreported. The source for insurance-reported collisions

screened to eliminate injury and/or towaway incidents, likewise remains

insurance claim files.

The survey was conducted under contract [17] over a period of six

months beginning in January 1985. Hhile this method is designed to

primarily obtain data on unreported collisions, insurance reported cases

were also counted (in contrast to the survey in 1979) in order to measure

the possible shift in damage severity that could occur as a result of the

bumper standard modification.

Insurance claim cases were obtained from the State Farm Insurance

Company computerized files and from a repair cost estimating service.

Both sources compiled data sets for the insurance data analysis conducted

under contract [1], [2], [3].

Throughout this report where data are collected using sampling

techniques, results are compared with their 95 percent confidence

intervals to determine if the result is statistically significant ( oi =>

0.05). If the result is within the range of the interval (+ or -) , it is

judged not to be statistically significant. If the result lies outside

the interval, the result is either significantly higher (an increase) or
lower (a decrease). All terms used in reference to a result's

significance are defined in terms of statistical significance as stated

here.

3.3 The Driver Survey

The driver survey was conducted under a design that would yield a

sample of U.S. households who owned or had exclusive use of 1981 through

1984 model year passenger cars. The key measures to be obtained from the

survey include:

o The frequency of low-speed collisions;

o The proportion of such collisions resulting in damage;

o The proportion of damaged cars in which an insurance

claim was filed or a police report prepared.

o The extent of damage; and

o The amount of owner/driver time and inconvenience

resulting from a damaged car.

This survey, in comparison to the one performed in 1979, included

questions relating to insurance claims (although the protocol was an

abbreviated version for these cases) and questions about delay and

inconvenience - the time spent at the collision scene, in filling out

accident reports and insurance claims, in getting repair estimates, in

having the car repaired, as well as the time the respondent was without

use of the car, and which substitute transport modes were used during that

time.

35
3.3.1 Survey Design

A total of 84,578 households were screened by telephone using

random digit dialing procedures. Eligible vehicles (1981 through 1984

models) were located in 20,915 households which yielded 2,823 qualifying

(no injury, car driveable) bumper incidents. The data base consisted of

the separate surveys - an initial and a follow-up survey - each using a

four-month retrospective reporting period.

Two potential problems in designing a survey are memory decay and

telescoping. Memory decay is a significant problem on surveys in which

respondents must retrospectively report over a large period of time,

particularly when trying to recall relatively minor incidents. This

problem can be alleviated by appropriate questioning. The techniques

employed in the survey used an unaided question followed by a series of

aided questions to optimize incident recall. The other potential problem,

telescoping, consists of a reported event being displaced in time. By

using only a four month retrospective reporting period the effect of

telescoping was judged to be self cancelling [17].

Following the practice of the 1979 survey which showed no

significant difference in damage reported by the respondent and damage

observed by inspection of the car on site, in-person visits were

conducted. These were limited to 3 percent of the total incidents

involving damage. The inspections largely substantiated the accuracy of

damage reported in the survey.
The survey methodology 1s described in detail in the reference

indicated above, to which the survey instrument is appended.

3.3.2 Collision Damage Frequency - Results of the Driver Survey

It will be recalled that the primary purpose of the driver survey

was to obtain data on unreported, low-speed bumper-related collisions.

The results will, 1n a subsequent chapter, be combined with insurance

claim data to determine net changes in benefits associated with the bumper

standard's modification. In Tables 3-1 through 3-3, damage incidence of

1983 and 1984 cars are compared to their respective 1981 and 1982

predecessors, both for cars with changed as well as unchanged bumper

systems.

Table 3-1 shows the effect of low-speed collisions on changed

(i.e., reduced strength) 1983 bumper systems. Overall there is a drop in

the frequency with which these bumpers are damaged. However, when broken

down between front and rear incidents, there is no statistically

significant difference between changed 1983 bumpers and their 1981/82

predecessor systems—relative to differences for systems that were not

changed, i.e., when bumper strength remained at prior levels.

The 1984 bumper model experience is shown in Table 3-2 with

results opposite to those for 1983 bumpers. In essence, 1984 bumpers had

a higher damage frequency than their 1981/82 predecessors. This

difference was, however, not statistically significant.

37


Combining the two model years before and after the bumper

standard modification yields a larger sample size, and the comparison is

shown in Table 3-3. The net difference in collision damage frequency,

when comparing changed 1983/84 bumper systems to their 1981/82

predecessors, is essentially nil. This may appear to be counterintuitive

since one might expect a larger incidence of damage to bumpers and other

parts when protected by systems with lesser strength. The fact that these

data are based only on unreported incidents likely screens out the more

severe damage cases which are reported.

3.3.3 Damage Repair Cost - Unreported Low Speed Collisions

Damage repair costs for 520 cases of unreported low-speed

collision damage were estimated (under a separate contract). The cases

covered the 1981 through 1984 model years. While these data will be

combined with much larger insurance claim case files for the overall net

benefit analysis, it is of interest to see both the repair cost level and

trends for bumper systems that were changed as a result of the bumper

standard modifications.

Table 3-4 shows the net repair cost differences - and their

statistical significance - between changed and unchanged front and rear

bumper systems. The comparison first establishes differences between

respective changed and unchanged 1983 + 1984 vs 1981 + 1982 predecessor

models. Then the net differences between changed and unchanged are shown

AO


followed by an indication of whether changed 1983 and 1984 bumper system

collision repair costs were significantly higher or lower or whether there

was no significant difference relative to unchanged bumpers.

Both the front and combined front and rear results show no

significant differences between pre/post changed bumper systems. The

average repair cost of unreported rear end collisions with damage is

significantly lower for cars with changed bumper designs as compared to

their predecessors and to cars with unchanged designs. This can be

accounted for by the fact that more bumper-involved rear end collisions

for the changed bumper group were reported to insurance companies (as will

be shown later). This would occur if changed bumper designs resulted in a

greater amount of damage which would cause people to place an insurance

claim. The net effect of an increase in insurance claims is to leave a

group of lower cost unreported cases in which damage occurred.

The survey data, in summary, indicates that little, if anything,

has changed for cars with modified bumper designs in 1983 and 1984 when

these are compared to their 1981 and 1982 predecessors. The frequency

with which damage occurs has essentially remained the same for incidents

that are not reported and for which no insurance claim is filed—although

it is possible that there are more cases of extensive damage which would

not show up in the survey. The cost to repair damage has not changed

either, with the exception of repair cost to the rear bumper and rear body

43
area. That has declined significantly and analyses of insurance claims

and parts damaged in the following sections may explain the reasons for

lower repair costs for rear end damage.

3.3.4 Damage to Parts in Unreported Low Speed Collisions

One method for determining the magnitude of damage in unreported

low-speed collisions is to count the number of damaged parts. The bumper

standard specifies that certain safety-related parts remain undamaged or

at least continue to be operable after impact testing. Damage limitations

also apply to certain front and rear exterior sheet metal parts. The

following list contains the parts that were included for damage screening

in the survey of unreported collisions.

Front bumpers Rear bumper

Grille Rear lamps

Front lamps Rear reflectors

Front reflectors Right rear fender

Front right fender Left rear fender

Front left fender Trunk lid

Hood Trunk latch

Hood latch Tail pipe

Radiator Fuel tank or filler neck

3.3.4.1 Number of Parts Damaged

Table 3-5 is a distribution of unreported collisions by the

number of damaged parts. These data are from the driver survey (another

similar data set will be shown later, based on insurance claim cases).

The statistical analysis included in the table shows mixed

results for damage to safety-related and other bumper protected parts in

models equipped with changed (i.e., reduced strength) bumpers.

The significance tests reveal shifts from 1983 to 1984 relative

to 1981/82 models in each group—no damage, one, two and three or more

parts damaged—that appear to signal reversals. For example, in 1983

there was a significant reduction in collisions where a one or two parts

were damaged. In 1984 models, these groups were not significantly

different when compared to the 1981/82 pre-standard modification base. In

the case of three or more damaged parts, 1984 models experienced a

significant increase.

To determine the total effect of changed bumpers on damage to

safety-related and other parts, the 1983 and 1984 data were combined and

the damage percentages summed after weighting each category by the number

of damaged parts. Using this approach, the net difference between changed

and unchanged bumpers in terms of damaged parts, is 1.2% and the 95%

confidence Interval is ± 3.5%. This means there is no statistically

significant difference in the aggregate in the number of damaged parts for

changed versus unchanged bumpers.

3.3.4.2 Severity of Damage to Parts

In addition to the number of parts, the damage severity for

changed and unchanged bumper systems is of interest. For this purpose a

classification of severity and descriptive terms for such a classification

were provided to respondents in the survey. The survey in 1979 used these

levels of damage severity - major, moderate, minor and none. This proved

46
to be excessive since most major damages required part replacement and

minor damage was repaired. The current survey used major, minor and none,

with relevant examples of what each category could involve.

Tables 3-6 and 3-7 show damage severity for each of nine front

and nine rear parts, respectively. Each table is broken down into changed

and unchanged bumper design groups. Analyses are provided at the bottom

of each table on whether or not there is a significant difference in the

percentage of parts suffering major or minor damage in 1983 or 1984, in

contrast to 1981/82.

For changed bumper designs there were significantly fewer front

parts with either major or minor damage—both in 1983 and 1984. Only

right front fenders showed an increase—in minor damage—in 1983, and in

1984 there were more cases of minor damage to front lamps.

In the case of rear end damage, Tables 3-7, the first year (1983)

that changed bumper designs were on the road, they incurred a lesser

amount of damage overall, but in 1984 there was a significant increase in

the extent of damage to parts, particularly the rear bumper itself, and to

the fenders.

Given the sample size, it is difficult to show conclusions for

each post-standard model year. It appears that in the aggregate there is


no significant difference between changed and unchanged bumper designs in

terms of damage severity to safety-related and other bumper protected

front and rear parts.

3.4 Insurance Claim Data

Collision and liability are the two major forms of property

damage insurance coverage. Collision insurance provides protection for

damage to the insured driver's car. Liability insurance protects the

driver at fault by paying for damages to the other car (liability claims

are also made for personal injury, but such accidents are not included in

the definition of low-speed collisions in this evaluation).

The objective in analyzing insurance claim data is to establish

the change 1n both damage frequency and claim amount which can be

attributed to the modification of the bumper standard. These measures

again require that claim cases: (1) be screened to exclude injury and

towaway incidents; and (2) be limited to front and rear bumper-related

collisions. A detailed discussion of sources is included in the April

1981 evaluation of the bumper standard [103. The same sources and

approaches are used in this evaluation. Specifically, the computerized

State Farm Insurance Company file was selected as the primary source of

insurance data. It contains the detailed data needed to evaluate bumper

effectiveness, for the years 1981 through 1984, and includes both

collision and liability claim data. To check the representativeness of

the single main data source, it was compared to the distribution of claim

'30
frequency and damage repair cost obtained from an estimating service which

obtains case files from a number of insurance companies. An additional

source, the Highway Loss Data Institute (HLDI) provides information on

collision claims (not liability claims) for many major insurance

companies, including State Farm, and this source was used to determine the

average loss payments per insured vehicle year.

3.4.1 Description of State Farm Files

State Farm Insurance Company maintains a detailed data file of a

sample of claims made at its drive-in claim centers throughout the

country. File tapes are assembled for each model year containing both

collision and liability claims data. In 1983, the first model year to

which the modified bumper standard was applicable, State Farm began to use

a computerized estimating service - ADP Collision Estimating Services Inc.

(Audatex System) - for processing damage claims at many of their drive-in

service centers. Other centers continued to use "manual" procedures that

had been in place prior to 1983.

Comparing the results of automated with manual estimates (for

example 1983 yj. 1982) yielded consistent differences in both the amount of

damage repair cost - and the proportion of bumper-related claims to all

claims. Further research into the data tapes by the insurance data

analysis contractor (KLD Associates, Inc.) revealed that computer

estimates (by the estimating service) contained claims with severe

51
damage. They also found claims in the manual estimates which included

towing charges reflecting a collision severity which was to be excluded,

as previously noted. The computer estimates included cases where State

Farm representatives performed a field inspection of damage since the

vehicle was not driveable. Such cases were, as before, not to be included

in the analysis. Removing towables by an appropriate filtering method

yielded data sets which were usable for comparative analysis.

In preparing data sets for analysis, every effort was made to

assure year to year compatibility. The various data set adjustments,

including testing by the contractor and the recommendations for use, are

documented in the contractor final reports [13, [23, [33. In each case

the largest possible case file was utilized and, for the years in which

both manual and automated procedures were used to estimate repair costs or

to identify bumper related cases, both sets were combined.

Three basic comparisons are made for changed and unchanged bumper

systems between pre- and post- bumper standard modifications. The

relative net change in effectiveness (pre/post) is derived by the

difference in damage frequency and damage repair cost between changed and

unchanged bumper systems, as was done for the data sets used in the

analysis of unreported collisions in the previous sections. As has

already been stated, the pre/post comparisons always involve matched data

for changed and unchanged bumper systems. For example the 1983 changed

bumper systems are compared to their 1981/82 nameplate predecessors.

5?
3.5 Analysis of Effectiveness Based on Insurance Claims Data

The reduction of the bumper standard from 5 to 2.5 mph could have

several effects. It could increase the rate at which bumpers are damaged

in a low-speed collision. The cost to repair the damaged bumper system

will vary depending on the extent of damage and whether it is repaired, or

if several parts have to be replaced. Both measures - the proportion of

bumper damage claimed to all claims, and the average damage repair cost -

are presented and discussed in the following sections.

3.5.1 The Proportion of Bumper Related Insurance Claims

The insurance claims data base consists of a sample of property

damage insurance claims, which include those that involved the bumper

(both front and rear). The objective, in this section, is to determine

the difference between the claim made for collisions involving cars with

changed bumpers compared to claim rates for unchanged designs. Table 3-8

shows that net difference - and its statistical significance - between

changed and unchanged bumper insurance claim rates.

In every case there has been a significant increase in the

proportion of claims for rear end bumper-related collisions, which, when

combined with claims for front end damage, also show a significant

increase for 1983 and 1984 models.

53

Beyond a fairly low impact speed, the bumper offers little or no

protection. In frontal collisions, the bumper is less of a factor in

preventing damage since these generally involve higher impact speeds than

rear collisions. Therefore, damage is more likely when rear bumpers are

built to a reduced standard.

3.5.2 The Average Repair Cost of Bumper Damage Based on Insurance Claims

The average repair costs for bumper-involved claims for the 3

sets of comparisons are arrayed in Table 3-9 in the same format as the

claim frequencies. It shows the average repair costs and the net

differences between changed and unchanged post-standard bumper systems

relative to their pre-standard predecessors.

The cost to repair collision damage, based on insurance claims,

averages $1000, compared to $450 when collision damage is not reported and

claimed under insurance coverage. Repair cost dropped by $62 for 1983/84

models compared to their 1981/82 counterparts, largely the result of less

expensive bumper systems.

Those models which were equipped with changed (reduced strength)

bumpers encountered a significant decrease in damage repair cost for 1983

and 1984 models as well as for the aggregate of both years.

55

The Insurance repair estimates for frontal and rear damage claims

declined significantly, a $36 net differential for frontal and $38 for

rear claims, based on the relative differences between changed and

unchanged bumpers. Claims for frontal damage of 1983 models was slightly

lower than for 1984 models but both showed statistically significant

decreases in average repair cost for changed bumper designs. Rear end

claims showed a somewhat different change -- 1983 models with changed

bumpers had a higher average repair cost whereas 1984 models showed a

significant decrease. In the aggregate, rear claims had significantly

lower changes in repair costs in about the same magnitude as frontal

claims.

Much of the reduction in average repair cost can be attributed to

lower costs of changed bumper systems. The repair cost reductions are

larger than the estimated reductions in consumer cost of bumpers. This

can occur because automotive replacement part costs are generally about 4

times higher than the original consumer cost.

3.6 The Effect of the Type of Bumper System Changes Made in

Response to the Bumper Standard Modification

As will be recalled, the changes made to 1983 and 1984 bumper

systems were analyzed and placed into four categories: Facebar,

Structural, Energy Absorber, and the combination of Structural and Energy

Absorber. Each category had different effects on the weights and costs

of bumpers and this section explores these effects on damage frequency and

its average repair cost. Since each of the categories is a subaggregate

57
of all changes combined, the data sets are smaller, and in order to have

enough of a sample size to show statistical significance, only one

comparison is made - 1983 and 1984 y_s 1981 and 1982 cases. Tables 3-10

and 3-11 show the damage frequency and average repair costs for each

category, respectively.

3.6.1 Damage Frequency by Change Category

The proportion of bumper-related damage claims for cars with

bumper systems that were not altered (after the standard was modified to

2.5 tnph) did not change in relation to the experience of their 1981/82

predecessors. This was already shown in Table 3-8; the values

(proportions) are listed in Table 3-10 merely for comparing the proportion

levels to the change categories.

Statistically significant increases in the proportion of damage

claims were found in cases where thickness (gauge) of the bumper's facebar

was reduced, and also where structural parts (reinforcements, brackets,

etc.) were either eliminated or reduced in size. These two change

categories represent 17 and 24 percent of the cars produced in 1983 and

1984, respectively. In both of these categories, damage to the rear of

the struck cars contributed to the significantly higher damage rate. It

was the 1983 and 1984 GM compacts and subcompacts such as the Citation,

Skyhawk, Chevette, and Century models that had downgauged facebars, and

Chrysler Reliant, Omni and the 400 as well as the Honda Civic and Accord

5 8

TABLE 3-11

AVERAGE DAKAGE REPAIR COST FOR BUMPER RELATED INSURANCE CLAIMS

By Design Change Categories 1/

Net Difference Between Changed and Unchanged Bumper Systems

1983+1984 vs. 1981 +1S82

(1984 Dollars)

UNCHANGED BUMPER SYSTEMS CHANGED BUMPER SYSTEMS

CHAHG8 CATEGORY 1/

Facebar

Front -i- Rear

Front

Rear

Structural

Front T Rear

Front

Rear

Energy Absorber

Front + Rear

Front

Rear

Structural s Energy Absorber

Front + Rear

Front

Rear

A. B.

1983+1984 1981+1982

C.

(A-3)

41003

$1112

$838

£iG03

$1112

$838

il003

$1112

$838

$1112

$838

£1181

$982

tJ.105

fll81

$982

fcllOS

£1181

$932

fcilOS

$1181

$982

-$102

-$69

-$144

-$102

-$69

-$144

-$102

-$69

-$144

-$102

-$69

-$144

1/ see section 2.1.4 for deelgn change category definitions.

2/ 95 Percent Conficence Level

3/ Significant>0 where Ho: pl=p2 vs. HI: pl>p2, Alpha=0.05

D. E.

1983+1984 1981+1982

SB 27

&9S2

$710

$962

$1096

$820

$973

$1102

$835

:>S48

IS881

!>793

F.

(D-S)

$962 -$135

$1048 -$66

$895 -$185

$1060 -£98

$1172 -$76

$937 -$117

$1083

$1225

$9 21

$1049

$995

$1104

Net Diff.

(F-C)

Conf. 2/ Significant

Interval Incr. or Deer, of

- or + Changed Bumper Systems 3/

-$33 11 Signif. Decrease

+$3 15 No Signif. change

-$41 19 Signif. Decrease

+$4 11 No Signif. Change

-$7 18 No Signif. Change

+$27 16 Signif. Increase

-$8 72 No Signif. Change

-&54 110 No Signif. Change

+$58 70 No signif. Change

-$99 22 Signif. Decrease

-$45 19 Signif. Decrease

-$167 51 Signif. Decrease
that reduced or eliminated structural parts, together with substituting

brackets for hydraulic energy absorbers in 1983. The complete list of

make/models by change category for 1983 and 1984 is in Appendix D.

Where only the energy-absorbers were removed, and replaced by

bracketry—and this group represents only 2 percent of the production

fleet in 1983 and 1984—no significant change in the proportion of

bumper-related collision damage could be detected. Of the bumper systems

analyzed, approximately 60 make/models for each of the 4 model years, only

Chrysler models, specifically the LeBaron, 600, E Class and New Yorker

were in this category. It is possible that sample size may be a factor

since there were only 500 bumper claims cases in this sample set in

contrast to between 6000 and 12,000 for the other design change

categories. It would, in any event, take a sizeable sample to detect even

a small claim rate change.

There was a significant increase in damage claim rates for cars

whose bumpers underwent certain structural changes, such as reducing or

eliminating reinforcements to the facebar, eliminating brackets, pads,

etc. These changes, in 1983, were made to intermediate and larger GM

models such as the Bonneville, Cadillac, LeSabre, Electra and Camaro, and

were extended to the Cavalier, and Chevrolet group in 1984. Nissan's

Sentra, the Toyota Tercel, as well as the Volvo models, were also in this

category. The increase in damage rate appears to be borne equally by

front and rear collision cases. The production/sales volume of cars whose

bumpers incorporated this change was 15 percent in 1983 and 25 percent in

1984.

61
3.6.2 Average Repair Cost by Change Category

Bumpers which were subjected to the more extensive design changes

appear to cost significantly less to repair after a collision. As Table

3-11 shows, the combination of a structural revision and the elimination

of hydraulic energy absorbers produces a significant decrease in damage

repair costs—an aggregate of $99 per front or rear incident. As

mentioned in the last section, this category contains primarily Chrysler

Reliant/Aries, Omni/Horizon, and Honda Accord/Civic models in the

make/model sample used in this evaluation.

The category which includes intermediate and large GM models,

Nissan's Sentra, the Toyota Tercel, and Volvo models showed that as a

result of structural changes (e.g., bumper reinforcement or bracket part

reductions) there was no significant change in repair costs overall, but

that there was a significant increase in repair cost attributable to rear

end collisions.

Each change category either showed a significant decrease or no

change in damage repair costs relative to 1981/82 predecessor incidents,

except for incidents involving rear bumpers whose changes were in the

structural category. The effect of just eliminating energy absorbers,

while only applicable to about 2 percent of the cars produced and/or sold

in 1983 and 1984, shows no significant change in repair cost, although as

already mentioned, the sample size is relatively small (about a 10 percent

sample would be needed to judge significance).

6 2
The overall trend for 1983 and 1984 model collisions shows a

tendency for damage to occur more frequently, although at a lower repair

cost, than the 1981/82 predecessors of the models whose bumpers were

changed.

3.7 Damaged Parts in Collisions for Which an Insurance Claim was

Fill

Property damage claims were screened to identify those insurance

claims where any of the following parts v/ere damaged: headlamps, parking

lamps, tai1 lamps, hood, radiator, trunk and fuel tank. This list is

shorter, and less specific, than the one used in the driver survey. The

limitation is due to the fact that while repair cost estimates are based

on all damaged parts, retrieval of this computerized information depends

on widely differing manufacturer part numbers.

Lamps represent one third of all parts cited in insurance claims

and, as Table 3-12 shows, this percentage holds for both the changed and

unchanged bumper systems in model years 1983 and 1984. There is also no

significant difference in the incident rate for lamp damage between the

changed 1983/84 bumper systems and their 1981/82 predecessors.

The other safety-related parts—hood, radiator, trunk and fuel

tank, excluding hood latches, showed no significant change in damage

frequency between 1983/84 modified designs and their 1981/82 predecessors,

and the hood mechanisms are only a small portion of damaged part claims in

any case.

63
3.8 Bumper Mismatch in Unreported. Low Speed Collisions

As expected, since the bumper standard modification in 1982 did

not change the bumper height requirements (16 to 20 inches above road

level) there was no significant difference in incidence of over- or

underride. Table 3-13 shows the bumper contact frequency, which, while it

indicates a small net increase in cases where bumpers met—and conversely

would result in a lesser frequency of bumper over- or underride, is not

statistically significant between the 1983/84 changed bumper systems and

their 1981/82 predecessors.
TABLE 3-12

FREQUENCY OF DAMAGED PARTS IN BUMPER RELATED INSURANCE CLAIMS

FRONT AND REAR COMBINED

Net Difference Between Changed and Unchanged Bumper systems 1/

(Percent Present in Claims)

1983+1984 vs. 1981 +1982

UNCHANGED BUMPER SYSTEMS CHANGED BUMPER SYSTEMS

PART

Headlamps

Tailamps

Parking Lamps

Total Lamps

Hood

Radiator

Trunk

Fuel Tank

A.

1983+1984

10

11

16

37

19

4

5

1

B.

1981+1982

15

8

10

33

16

4

5

1

C.

(A-B)

-5

+3

+6

+4

+3

0

0

0

1/ See Section 2.1.4 for explanation of changed bumper systems.

2/ 95 Percent confidence Level

3/ Significant >0 where Ho: pl=p2 vs. HI: pl>p2, Alpha=0.05

D.

1983+1984

13

11

13

37

21

3

5

1

E.

1981+1982

15

8

10

33

16

4

5

1

F.

(D-E)

-2

+3

+3

+4

+5

-1

0

0

Net Diff. Conf. 2/ Significant

Interval Incr. or Deer, of

(F-C) - or + Changed Bumper systems 3/

+3 1 Signif. Increase

0 1 No Signif. change

-3 1 Signif. Decrease

0 1 No Signif. change

+2 1 Signif. Increase

-1 1 No Signif. Change

0 1 No Signif. Change

0 1 No Signif. Change
TABLE 3-13

FREQUENCY OF BUMPER CONTACT IN TWO CAR UHREPORTED COLLISION

Net Difference Between Changed and Unchanged Bumper Systems 1/

(Percent of Collisions where Bumpers Met)

1983+1984 VS. 1981 +1982

UNCHANGED BUMPER SYSTEMS CHANGED BUHPER SYSTEMS

End of Respondant's car

Pront

Rear

A.

1983+1984

83

88

B.

1981+1982

82

34

C.

(A-3)

+ 1

+4

1/ See Section 2.1.4 for explanation of changed bumper systems.

2/ 95 Percent Confidence Level

3/ Signif icant >0 where Ho: pl=p2 vs. HI: pl>p2, Alpha=0.05

D.

1983+1984

85

88

E.

1981+1982

82

84

F.

(D-E)

+3

+4

Net Diff.

(F-C)

+2

0

Conf. 2/

Interval

- or +

4

3

Significant

Incr. or Deer, of

Changed Bumper Systems 3/

No Signif. Change

No Signif. Change
CHAPTER 4

BENEFITS AND COSTS

The basic measure used to determine the effects of the

modification of the bumper standard from 5 mph (Phase II) to 2.5 mph

(Phase I) is the change in net benefits (in dollars). Net benefits are

the difference between the change in lifetime benefits and the change in

lifetime costs of bumper systems for the respective pre- and post-standard

systems. The change in lifetime benefits is based on differences in

damage repair costs for the total number of low-speed collisions that

occur in an average car's life. The change in lifetime costs includes the

difference in bumper system costs to the consumer plus the fuel costs

attributable to the bumper weight change. Since both benefits and costs

involve consumer dollar outlays, the change in net benefits can also be

thought of as a change in costs to consumers.

This approach is identical to one used in the bumper standard

evaluation published in 1981 CIO] except that in the present case the

relative differences between bumper systems that remained unchanged (the

control group) and those that changed in 1983 and 1984 (relative to their

1981 and 1982 predecessors) must be taken into account.

67
This chapter addresses the calculation of relative net benefits

using the following steps (a detailed model with definitions is included

in Appendix E.):

o Description of factors involved in the calculation of

lifetime benefits and costs.

o Calculation of lifetime benefits,

o Calculation of lifetime costs.

o Relative net benefits as a result of the bumper standard

modification.

4.1 Description of Factors Involved in the Calculation of Lifetime

fits, iind jCpj. is.

Several factors, which are either part of the net benefit

calculations or which constitute the basis for assumptions, are described

in the following paragraphs.

4.1.1 Sfilfi£tifln_Qf .J

In cases where bumper cost or damage repair cost data were

reported or estimated at their current year prices, inflation factors were

applied to convert these to 1984 dollars. Bumper costs were adjusted

using the Bureau of Labor Statistics Consumer Price Index (CPI) for new

car prices. Damage repair cost estimates for both unreported incidents as

well as insurance claims were adjusted using the CPI for auto maintainance

and repair.

68
4.1.2 Establishment of a Base Year for Analysis

In order to compare dollar values of benefits and costs from

different time periods, a base year is established to which the other

years' dollar values are adjusted. The year 1984 was selected since it

was the latest full year for which actual economic data were available at

the time this evaluation was reaching completion. While the survey of

unreported low-speed collisions was conducted in the first half of 1985,

all repair cost estimates for cars with collision damage were in 1984

dollars. Insurance claim damage repair estimates which were obtained for

1981 through 1984, following each respective calendar year, were adjusted

as necessary. Analyses of bumper cost to the consumer, which were

conducted for each of the four model years in this evaluation, were

adjusted as well.

4.1.3 Controlling for a Changing Vehicle Size Mix

During the time period under consideration, the vehicle size mix

changed relatively little. Major downsizing programs resulted in the

introduction of many new nameplates in 1981 - the Chrysler K cars, Ford

Escorts, and GM 3 and A series. Average curb weights for the 1981 through

1984 model fleet were 2863, 2694, 2778, and 2780 pounds, respectively.

69
In order to ensure that differences in net benefits and costs

reflect the effect of the bumper standard modification, the vehicle mix of

1984 model cars sold in 1984 was used as the constant vehicle mix for

weighting and calculating: (1) the proportion of bumper-involved

insurance claims, (2) the repair cost for damage in bumper-involved

insurance-claimed crashes, and (3) the incremental consumer cost of the

standard modification.

4.1.4 Low-Speed Collisions Reported to the Police

A low-speed collision - one that results in property damage - may

have to be reported to the police. This depends on dollar value

thresholds which vary from State to State. Generally, if an injury

occurs, the collision must be reported. For some of the property damage

collisions, although a police report is completed, no insurance claim is

filed since the estimated repair cost is about the same as the deductible

amount in the driver's insurance policy.

The driver survey showed that about 6 percent of the low-speed

collisions involving the bumper were reported to the police only - no

insurance claim was filed. Given that collisions reported only to the

police represent a relatively small portion and that the cost of damage

repair is probably quite close to that of an unreported collision, they

are grouped with the latter. Damage descriptions for police reported

collisions were combined with the unreported collisions to compute average

repair cost estimates.

70
4.1.5 Effect of Secondary Weight

According to auto manufacturers, certain design characteristics

affect the weight of dependent systems such as the suspension, brakes,

frame, etc. A bumper weight change would tend to have a secondary effect

on the design of load and/or power related systems. When a bumper's

weight is measured, a proportional increase is also assigned to these

other systems - and is referred to as the "secondary weight." A decrease

in bumper weight relative to preceding models would likewise involve a

weight reduction to dependent systems. Both the 1981 bumper evaluation

[10] and the 1982 Final Regulatory Impact Analysis (FRIA) [9] include

discussions of the subject and use various secondary weight factors in the

analytic process.

Secondary weight factors ranging from 0.35 to 1.0 pounds of

secondary weight per pound of primary weight change were used in the 1981

evaluation. The FRIA was based on factors of 0.7 and 1.0, and these

values are used here in addition to the base net benefit calculation which

excludes the effect of secondary weight (i.e., secondary weight factor =

0 ) .

There are two costs associated with secondary weight - consumer

cost of the weight increment and the effect on lifetime fuel cost. Since

secondary weight is assigned to a variety of dependent systems an average

cost per pound is derived.

71
The FRIA used a cost of $0.60 per lb. (in 1981 dollars) which

reflected the cost of added material plus the variable manufacturing

cost. These costs were in turn derived from teardown studies and auto

manufacturers comments to the bumper docket in 1981 and 1982. Using the

ratio of 1984 to 1981 Consumer Price Indices for new car prices, a value

of $0.66 is obtained for 1984.

The lifetime fuel cost for the secondary weight increment is the

product of the lifetime fuel requirements (1.25 gallons per pound as

calculated in Appendix E) , the cost of fuel (see Appendix E) , the change

in weight due to the standard's modification, and the secondary weight

factor.

4.1.6 Collision Incident Rates

The low speed collision incidence rate of all cars on the road

each year is a measure of the frequency with which cars are involved in

collisions where no insurance claims are filed - although damage may have

been sustained. The driver survey yielded 1829 such collisions over an

eight month period from a population of 22,393 cars of model years 1981

through 1984 in the survey. This comes to a 12.2 per cent annualized

involvement rate.

72
The range based on a 95 percent confidence level is from 11.9 to

12.6 percent -- and the incidence rate for each model year (1981, 82, 83

and 84) fell within this range. The average annual value found from the

survey is slightly lower than the 13.7 percent found in the survey

performed as part of the bumper evaluation completed in 1981. At that

time the surveyed population covered 15 model years and included about

half as many cars in total. Factors peculiar to the two different time

periods (1979-80 versus 1985) such as weather, road conditions, vehicle

mix, traffic laws (right-turn-on-red) and their enforcement and economic

conditions might account for the differences.

4.1.7 Discounting Applicability and Methods

Discounting is the process by which a future stream of benefits

are valued in present dollars. The purpose of the calculation is to bring

expected benefits that accrue over varying future car lives back to a

common base in order to obtain a comparative present value of net

benefits. The discounting process is applicable to the "benefit" side of

the equation since it measures the difference in lifetime dollar values

of damage repair cost per car, per collision. It also applies to fuel

costs over a car's life - fuel costs being part of the "cost" side of the

equation. The cost of the bumpers and cost differences between pre- and

post-standard modification models are not subject to the discounting

procedure since their costs are in "present" terms (adjusted to 1984

dollars) and essentially disposed of when purchasing a car.

73
For the purpose of discounting, a car's life is assumed to be 10

years during which it travels 95,345 miles (mileage is based on in-house

studies of vehicle mileage and survival data used for fuel economy). It

is also assumed that benefits will accrue on a mileage basis over a car's

life. Since the frequency of low-speed collisions is dependent, to a

certain degree, on the amount of miles a car is driven, the benefits will

also depend on mileage. To determine the rate that benefits accrue per

mile of driving, gross benefits are divided by lifetime vehicle miles.

Estimates of annual travel by car age, weighted by survival

probability each year and summed over 20 years, is 106,952 based on

current available data. This means that the sum for the last 10 years is

11,607 miles, and that during the first 10 years 90 percent of the total

miles are accumulated. To discount future benefits properly, the miles

driven each year are discounted back, to the current time using the

discount factor for each year. Then the total discounted miles are

divided by the actual miles to establish the gross discount factor. Table

4-1, using a 10 percent discount rate, shows how a gross factor of .7393

is derived.

Future benefits are discounted to the year of purchase, except

they are stated in 1984 dollars. A 1984 model year car, for example, is

considered to be new with ten years to go for discounting purposes. A

sample procedure for a discount calculation is included in Appendix F. A

discount rats of 10 percent is used throughout [15] (see Table 4-1).

74

4.2 The Effect of the Bumper Standard Modification in Terms of

Benefits and Costs

This section presents and discusses the results obtained by a

comparative analysis of the changes in benefits and costs for bumper

systems manufactured before and after the modified standard. As we have

seen, there is a mix of both changed and unchanged systems, relative to

their pre-modification predecessors, in the respective 1983 and 1984 model

fleets. And as explained at the beginning of this chapter, it is the

relative net benefit between changed and unchanged bumper systems that

reflects the actual effect of the standard modification.

Before addressing this "bottom line" result, it is useful to

separate benefits from costs since the former is based on what happened to

changed bumpers in terms of damage incidence and the cost of damage

repair. Changes to bumper systems resulted almost exclusively in a weight

and cost reduction, as was shown in Chapter II, but it is important to

analyze the cost change separately with the attendant secondary weight and

fuel cost effects.

4.2.1 Incremental Gross Discounted Lifetime Benefits

The term "Incremental Gross Discounted Lifetime Benefits" means

the difference in damage repair costs between pre- and post-standard

bumper designs adjusted to present values via the discounting process. In

simpler terms, it is the monetary value of damage repair that is either

76
saved or has to be spent over the 10-year operating life of a car whose

bumpers are made to meet the 2.5 mph rather than the 5 mph standard. It

does not factor in the reduction in car purchase price, which at least in

theory would come from a less costly bumper system.

The incremental benefits (gross lifetime, discounted) are shown

in Table 4-2. They are listed for bumper systems that were changed as

well as those that remained essentially the same when compared to their

respective 1981/82 predecessors.

Compared to the typical lifetime discounted benefits — averaging

$600 and based on both insurance claimed and unreported repair costs —

the net difference between changed and unchanged bumper systems is small.

The $7 decrease in benefits shown for 1983 changed systems is not

statistically significant, although by 1984, there is a significant $66

decrease in lifetime benefits for the models whose bumpers were reduced in

strength — when compared to bumpers which were not changed.

When data for both post-standard model years are combined, the

outcome is a decrease of $36 in incremental lifetime benefits — which is,

however, not statistically significant.

The incidence and repair cost of damage to the rear of a car,

while averaging half that of frontal damage — $200 y_s $400 — is a main

contributor to a decrease in benefits over a car's lifetime if the car is

equipped with changed bumpers.

77

There appears to be a downward trend -- although not significant

so far for front bumper systems — for lifetime benefits (i.e., losses),

due to more frequent damage in bumper-related collisions on cars with

changed bumper systems.

The Final Regulatory Impact Analysis [9] prepared in 1982,

projected a $76 (in 1984 dollars) loss in gross lifetime benefits per car

as a result of the change from a 5 to 2.5 mph bumper standard. This value

was, however, based on the assumption that all of a year's new

production/sales would be equipped with bumpers designed to meet the

lowered 2.5 mph standard. So far this has probably not occurred, since

only half the bumpers were changed and the changed bumpers were not

necessarily designed for speeds as low as 2.5 mph.

4.2.2 Incremental Lifetime Costs

Weight and cost differences between the pre- and

post-modification bumpers were presented and discussed in Chapter II. The

incremental lifetime costs shown in Table 4-3 reflect the basic cost

difference between changed and unchanged bumper systems, adjusted for each

secondary weight (three different values are shown) and decreasing costs

of fuel over the car's 10 year life, discounted to 1984.

The effect of secondary weight is considerable. It nearly

doubles the lifetime cost of a bumper system when one pound of secondary

weight is added for each pound of primary weight.

79
TABLE 4-3

INCREMENTAL COSTS, INCLUDING LIFETIME DISCOUNTED FUEL COSTS 1/

Net difference Between Changed and Unchanged Bumper Systems 2/

(1984 Dollars)

UNCHANGED BUMPER

A. B.

SYSTEMS

SECONDARY

WEIGHT

FACTOR 3/ 1983

FRONT+REAH

FRONT

REAR

00

o

FRONT+REAR

FRONT

REAR

0.0

0.7

1.0

0.0

0.7

1.0

0.0

0.7

1.0

0.0

0.7

1.0

0.0

0.7

1.0

0.0

0.7

1.0

1981/82

C.

1983 Vs. 1981/82

(1983-31/82)

CHANGED

D.

1983

BUMPER

E.

SYSTEMS 2/

F.

1981/82 (1983-81/82)

1984 1981/82

1984 Vs. 1981/82

(1984-81/82) 1984 1981/82 (1984-81/82)

202

290

328

100

143

162

102

147

166

£228

$330

$373

ill3

^162

$183

fcll5

£168

S190

Net Diff.

Set (F-C)

FSONT+REAR

FRONT

REAR

0.0

0.7

1.0

0.0

0.7

1.0

0.0

3.7

1.0

1983+1984 Vs. 1981/82

1983/84 1981/82 (1983/84-81/82) 1983/84 1981/82 (1983/84-81/82)

1/ See Appendix E for equation defining "C"—Gross Cost.

2/ See Section 2.1.4 for explanation of bumper systems changes.

3/ See Section 4.1.5 for definition of secondary factor.
When bumpers were changed and their weight and cost reduced (in

1933/84) the drop 1n cost relative to unchanged bumper systems ranged from

$17 to $34 without secondary weight considerations. A larger lifetime

cost reduction of between $28 and $55 is attributable to a secondary

weight factor of 1.0

As was discussed in Chapter II, the first year's changes (1983)

to bumper systems reflected cases where relatively extensive design -- and

weight-- changes were made to selected nameplates, some of which reverted

to more damage resistant bumpers in 1984. This is reflected in the

overall results when in 1983 the net difference in lifetime bumper costs

(changed relative to unchanged bumpers) was a $53 reduction (0.7 secondary

weight factor) for both the front and rear systems. In 1984 the

equivalent reduction was $38.

Again, referring back to the 1982 Final Regulatory Impact

Analysis, the projected bumper system cost reduction, inflated to 1984

dollars was $91, an amount almost twice the $44 (at 0.7 secondary weight

factor) for the combined 1983/84 y_i 1981/82 comparison. Another

consideration here is the effect of a change in the way fuel costs are now

calculated. Using the 1.0 gallons/pound from the FRIA instead of 1.25

gallons/pound used in this evaluation would alter the $44 amount to $39.

81
4.2.3

Net benefits are the algebraic differences between incremental

gross lifetime benefits and lifetime costs which were presented separately

in the previous two sections. The net benefits, as already discussed, are

relative values since on-the-road experience by both the changed and

unchanged bumper systems in the post-standard model years (1983 and 1984)

is compared relative to respective predecessor experience in 1981 and

1982. Net benefits for each of the three pre- and post-comparisons are

shown in Table 4-4, The table gives net benefit outcomes for all the

major variables that constitute the evaluation.

Since the previous two tables list incremental gross lifetime

discounted benefits and costs separately, Table 4-4 shows only the values

of the net difference (Benefits less Costs) which are here designated as

relative net benefits. The relative benefit is the amount in dollars over

the 10 year life of a car that is either gained (benefit) or lost (loss or

disbenefit) as a result of the changes made to bumpers — in those models

where, in fact, system changes were made — to meet (or exceed) the

modified (2.5 mph) bumper standard.

Looking first at the combined front and rear results, it appears

that in 1983 the changed bumpers, those with a reduced strength relative

to their 1981/82 predecessors, yielded net benefits ranging from $31 to

$52 depending on the secondary weight factor. The 1984 changed models did

not

82

fare so well in comparison to their predecessors (and as normalized for

differences that affected unchanged bumpers). They show a net loss of

between $-24 and $-41 over the car's 10 year life. Given that the 1984

"changed bumper" fleet accounted for 51 percent of the new cars sold, up

from 35 percent for the 1983 fleet, and that the variance in insurance

repair estimates was large, the effect for 1984 is that there is a net

loss, but it is not statistically significant.

The relative "weight" of the 1984 statistics carries over into

the combined analysis — 1983/84 y_i 1981/82. Although this is the maximum

available data set, it still shows that there is no statistically

significant difference in net benefits (or losses) over a 10 year car

life. This is due to changed bumper systems and their low speed collision

experience (more accidents, less damage per accident), when compared to

cars still equipped (in 1983/84) with systems identical to their 1981/82

predecessors.

The $8 relative net benefits is comparable to a value of $15 (in

1984 dollars) projected in the 1982 FRIA ($28 in 1981 dollars and

methodology).

Separating the analysis into front and rear damage and bumper

cost effects shows that, for the 1983 changed models, the net benefit is

derived from the cost effectiveness of front bumper systems which yield a

$36 to $44 lifetime net benefit, in contrast to the rear bumpers which are

only a third as cost effective. Both front and rear 1984 changed bumper

84
systems show a net loss, but this is too small to be significant. When

the data for the respective two years before and after the standard's

modification are analyzed, front changed bumpers show benefits and rear

bumpers incur losses — but neither result is statistically significant.

The primary conclusion of the evaluation is that after two years

in which certain design changes were made to a growing population of

bumpers -- in response to a modified bumper regulation — the road

experience in terms of low-speed bumper-related collisions for the cars

with changed bumpers has remained the same as the experience with cars

equipped with bumpers manufactured to the previous 5 mph standard.

4.3 Effects on Net Benefits bv Type of Bumper Design Change

To establish the effects - incremental gross discounted lifetime

benefits, lifetime costs and relative net benefits - for each type of

bumper design change, the same procedures described in the previous

section (4.2) are used. Since sample sizes shrink in this subaggregate

analysis, only the comparison between the two post- and two pre-bumper

standard modification years is made.

4-3.1 Incremental Gross Lifetime Discounted Benefits bv Bumper DesIgn

Change Category

Table 4-5 lists the four change categories into which

make/models were placed after an analysis of changes to their bumper

85

systems to determine the type of change, relative to 1981/82 model

predecessors. Although not statistically significant in most cases, every

category contributed to a decrease in lifetime benefits (changed relative

to unchanged bumper systems) except for front bumpers whose energy

absorbers were replaced by rigid brackets. This category only represents

a small, two to three percent, part of the new car sales population in

each post standard year.

As can be seen in Table 4-5, reductions in facebar thickness

(downgauging) are significant contributors to lifetime losses, apparently

driven by repair costs for rear end damage. Structural changes,

particularly the elimination of reinforcement bars and reductions in the

size of brackets also lead to lifetime losses. Reducing the gauge of a

facebar could reflect the reversion to a Phase I bumper system, where

damage to the bumper itself is allowed, in contrast to Phase II where a

dent is to be no larger than 3/8 inch. With many designs incorporating an

elastomeric facia which covers metal facebars, this kind of damage also

becomes less visible.

Minor structural changes accompanying the replacement of energy

absorbers — found in 10 percent of the new fleet (1983 and 1984) — and

the relatively small number of designs where only energy absorbers were

replaced with rigid brackets, appear to lead to somewhat lower lifetime

loss values. However, as has already been pointed out, these results are

not statistically significant.
4.3.2 Incremental Lifetime Costs by Bumper Design Change Category

The lifetime cost of bumper systems, including the fuel penalty

and secondary weight effect for each of the four change categories, is

shown in Table 4-6. The analysis is limited, as in the previous section,

to a combination of 1983/84 vs. 1981/82 model years. Only values for a

secondary weight factor of 0.7 are shown.

Lifetime bumper cost reductions range from $28 to $55 for the

combined front and rear bumper systems. The latter value appears to be

attributable to rear bumpers whose only change in strength reduction is

the substitution of energy absorbers with rigid mounting brackets. This

is, however, only a very small population of the new fleet for 1983 and

1984 (approximately 2 percent) and the main contribution to weight

reduction is a downsized bumper system, or in some cases a substitution of

aluminum for steel.

Overall the lifetime cost of a typical bumper system is in the

$400 range for unchanged bumpers and between $250 to $400 for changed

designs, depending on the kind of change.

4.3.3 Net Benefits by Design Change Category

Table 4-7 summarizes the relative net benefits (and losses)

contributed by each of the four design change categories. In each case

the result is not statistically significant.

8 8

DESIGN CHANGE

CATEGORY 2/

TABLE 4-7

RELATIVE NET BENEFITS 1/

Net Differences (Benefits less Costs)

Between Changed and Unchanged Bumper Systems

By Design Change Categories 2/

(1984 Dollars and 0.7 Secondary Weight Factor) 3/

1983+1984 Vs. 1981/82

Relative Confidence Significant

Net Interval 4/ Incr. or Deer, of

Benefit - or + Changed Bumper Systems 5/

FRONT + REAR

Facebar -!

Structural -:

Energy Absorber +!

Structural + Energy Absorber

FRONT

Facebar -!

Structural -i

Energy Absorber +!

Structural + Energy Absorber

REAR

Facebar -i

Structural

Energy Absorber +i

Structural + Energy Absorber -;

54 2

525

565

-$9

)1 1

119

!3 3

i-$3

>3.l

-$6

?32

512

54

52

149

64

43

41

135

39

31

30

79

44

NO

No

No

No

NO

No

NO

No

NO

No

No

No

Signif.

Signif.

Signif.

Signif.

Signif.

Signif.

Signif,

Signif .

Signif.

Signif.

Signif.

Signif.

Change

Change

Change

Change

Change

Change

Change

Change

Change

Change

Change

Change

1/ See Appendix K for Algorithm defining net benefit.

2/ See Section 2.1.4 for for explanation of design changes.

3/ See Section 4.1,5 for definition of secondary weight factor.

4/ 95 percent Confidence Level.

5/ Significant>0 where HO: pl=p2 vs. Hi: pl>p2, Alpha=0.05.

90
I

The relatively larger net benefit values for the energy absorber

change category reflect a wide variation due to the small sample size in a

population that is only a 2 percent of new vehicle sales in 1983 and

1984. The other net benefit or loss amounts — over a 10 year lifetime --

are quite small so that in summary the overall results, which show no

difference between changed and unchanged bumper systems relative to their

respective 1981/82 predecessors, are not explained or further clarified by

disaggregation into design categories.

4.4 Effects of Additional Factors

The Motor Vehicle Information and Cost Saving Act [13] calls for,

in addition to the benefits and costs attributable to the bumper standard,

an accounting of the effects of insurance and legal fees and costs,

effects on consumer time and inconvenience and a consideration of health

and safety, including emission standards.

The driver survey, described and analyzed in Chapter III,

included questions on the time spent at the collision scene, in filling

out forms/police reports, in getting repair estimates, in getting the car

repaired, the time without the use of the car, and transportation

alternatives used when the car was unavailable as a result of a low-speed

collision.

91
The question of safety is essentially limited to the changes in

damage to certain vehicle parts such as lamps, latches, etc. The analysis

in Chapter III presented the results based on both the driver survey and

insurance claim data. Other aspects of the safety issue were discussed at

length in the FRIA of 1982 and no new data has emerged to change the

conclusions therein that there would be no adverse effect on

safety-related parts.

4.4.1 Time and Inconvenience

Persons whose cars were involved in low speed collisions in which

damage occurred were asked, as part of the driver survey, questions on

delay and inconvenience. Almost no difference was found in the amount of

time involved at the scene, filling out reports, getting repair estimates

and being without a car — when cars with changed bumpers were compared to

cars with unchanged bumpers. In summary, these time values are:

Time Period

At Scene 35 minutes

Filling out Forms 78 minutes

Getting Estimates 245 minutes

Total Time 358 minutes

Time getting car repaired 1-1/2 days

Time without use of car 2 days

92
About 15 percent of the persons with damaged cars in low speed

collisions, who chose to get their cars repaired, had to obtain alternate

means of transportation (other than from family members) while their car

was being fixed. These persons used a variety of modes. No reliable

out-of-pocket cost estimates are available.

The analysis in the 1982 Final Regulatory Impact Analysis assumed

the amount of time per damaged car was about the same regardless of bumper

design. The FRIA further assumed that the difference in delay time among

the car owners had to be caused by the number of low speed collisions with

damage that occurred during a cars' life. From both the driver survey and

insurance claim analysis, the lifetime number of low-speed

damaged-involved collisions is 1.07 for cars with unchanged bumpers and

1.14 for car with changed bumpers. The FRIA further assumed 1.5 people

were in the car at the time of a collision so that the 35 minutes spent at

the scene should be increased by 50 percent to 53 minutes. This means the

total time per damage collision is 6.3 hours. The FRIA also used an

average wage rate of $7.10/hour in 1981 and valued inconvenience at

$10-$25 per case. Bringing both these values to 1984 dollars yields $8.33

per hour and $12-$29 per case for inconvenience. Applying these rates to

the time per damage collision results in a $64-$81 cost per collision.

93
Combining the lifetime collision rates with the cost per collision

and discounting over a 10 year car life results in a cost of $50-$64 for a

car with unchanged bumpers and $54-$68 per car with changed bumpers. This

is a net increase in delay and inconvenience of $4, for owners of cars with

changed bumpers.

4.4.2 The Cost of Insurance and Legal Fees

No new information on the cost of insurance premiums and legal

fees was obtained as part of this evaluation. From data collected and

analyzed as part of the 1982 FRIA, 26 percent of insurance premiums are

essentially fixed costs per claim. Also the costs associated with legal

fees are incorporated in insurance premiums. Applying the 26 percent to

the portion of lifetime discounted benefits from insurance claims in Table

4-2, results in a $10 lifetime decrease in benefits for 1983/84 models

with changed front and rear bumpers when compared to models with unchanged

bumpers. Table 4-2 shows a $36 decrease in lifetime benefits for 83/84

front and rear models which would increase to $46 if fixed costs are

included. The confidence interval is + $54, therefore the finding in

Table 4-2, that there is no significant change in lifetime benefits,

remains.
4.4.3 The Effect of Damage Not Repaired

The current driver survey found essentially the same unrepaired

damage frequency as the 1980 survey—64 percent with unreported damage

went unrepaired (the 1980 survey found 69 percent). There was no

statistically significant difference between cars with different bumper

designs.

No additional information was collected on the value placed on

unrepaired damage by the public. When valued at 100 percent, unreported

damage amounts to about 20 percent of the gross discounted lifetime

benefits.

The 1982 FRIA valued unrepaired damage at 50 and 75 percent of

repair estimates to adjust for some vehicle owners not repairing the

damage. To completely evaluate the effectiveness of bumpers in reducing

repair costs, the total (100 percent) estimate to repair all damage —

actually repaired or not -- would be included. This evaluation, as in the

1981 evaluation, values unreported damage at 100 percent of repair

estimates. For comparison purposes with the 1982 FRIA, adjustments in

relative net benefits for unrepaired damage valued at both 50 percent and

at 75 percent have been calculated.

95
From the 1982 FRIA, the average consumer cost for damage when all

damage was repaired was compared to the average consumer cost when

unrepaired damage was valued at 50 percent and then at 75 percent. The

FRIA assumed that only 50 or 75 percent of the damage would be repaired at

lower speeds. For purposes of adjusting net benefits, ratios based on

averaging the FRIA data were used. The data base consisted of a

distribution of the number of lifetime accidents in each speed cell (e.g.,

0-3 mph, 3-4 mph, etc.) and the average repair cost within that speed

cell. Nith these data, weighted average lifetime repair costs were

estimated for 100, 75, and 50 percent repair values. The average repair

estimate for 50 percent and for 75 percent were each divided by the

average repair estimate for the 100 percent level.

The ratios of average consumer cost for 50 and 75 percent, when

compared to the average cost for 100 percent repaired damage, are 0.845

and 0.923 respectively. These ratios have been applied to the incremental

gross lifetime discounted benefits in Tables 4-2 and 4-5. The net effect

of valuing unrepaired damage at 50 percent and at 75 percent are shown in

Table 4-8. This shows a net decrease of $6 in gross benefits when

unrepaired damage is valued at 50% and a decrease of $3 when unrepaired

damage is valued at 75% for changed bumpers. Table 4-9 shows the

adjustment to net differences in gross benefits for unrepaired damage by

design change category. At the 50% level value for unrepaired damage, the

adjustment ranges from an increase of $1 to a decrease of $12. At the 75%

level the adjustment ranges from + $1 to -$6.

9 6
TABLE 4-8

ADJUSTMENT TO NET DIFFERENCES IN GROSS BENEFITS

(from Table 4-2)

(1984 Dollars)

UNREPAIRED DAMAGE VALUED AT

50% 25%

1983 vs. 1981/82

Front+Rear -1 0

Front +3+ 1

Rear -4 -1

1984 vs. 1981/82

Front+ Rear -10 -4

Front -5 -2

Rear -5 -3

1983 + 1984 vs. 1981/1982

Front+Rear -6 -3

Front 0 -1

Rear -6 -2

97
TABLE 4-9

ADJUSTMENT TO NET DIFFERENCES IN GROSS BENEFITS

By Design Change Categories 1^

(from Table 4-5)

(1984 Dollars)

UNREPAIRED DAMAGE VALUED AT

50% 75%

1983 + 1984 vs. 1981/82

CHANGE CATEGORY 1 ;

Facebar

Front + Rear

Front

Rear

Structural

Front + Rear

Front

Rear

Energy Absorber

Front + Rear

Front

Rear

Structural & Energy Absorber

Front + Rear

Front

Rear

-11

-3

-8

12

-7

-5

+1

+5

-4

-7

-2

-5

-6

-2

-4

-6

-4

-2

+1

+2

-1

-3

-1

-2

1/ See Section 2.1.4. for design change category definitions.

9 8
4.4.4 The Effect of High Speed Collisions.

The 1982 FRIA took into account the repair costs of cars with

different bumpers which were involved in high speed collisions in which

the car was not a complete wreck (totalled). The FRIA used 0.16 high

speed collisions per car over its lifetime and considered only the

difference in bumper replacement cost. Manufacturing variable cost is

marked up twice to obtain consumer cost: a factor of 1.437 is applied to

obtain wholesale cost, which includes overhead, and wholesale cost is

marked up by 1.14 to obtain dealer cost to the consumer.

Applying these factors to the bumper costs in Table 2-3 and

discounting over a 10 year car life results in an increase in gross

benefits of $4.

4.4.5 Interest Savings

The 1982 FRIA also considered the effects of changes in consumer

costs of cars for changes in bumper costs and secondary weight. A 10

percent interest rate was used in the FRIA which still seems appropriate,

and the cost of secondary weight is 66 cents per pound. Assuming a

secondary weight and using cost differences shown in Tables 2-4, 2-5 and

2-6 results in the adjustments to gross costs for interest savings shown

in Table 4-10 which were +$2 for all changed bumpers.

99
TABLE 4-10

ADJUSTMENT TO NET DIFFERENCE IN INCREMENTAL COSTS FOR INTEREST SAVINGS

By Design Change Categories 1/

(from Tables 2-4, 2-5, 2-6)

CJJAN£E_£AIESQBY

(1984 Dollars)

1983 +

1983 vs. 1984 vs. 1984 vs.

1981/82 1981/82 1981/82

Unchanged Bumpers

Front + Rear

Front

Rear

Changed Bumpers

Facebar

Front + Rear

Front

Rear

Structural

Front + Rear

Front

Rear

Energy Absorber

Front + Rear

Front

. Rear

Structural & Energy Absorber

Front + Rear

Front

Rear

All Changed Categories Combined

Front + Rear

Front

Rear

0

0

0

-2

-1

-1

-3

-2

-1

-3

-1

-2

-3

-2

-1

-3

-1

-2

0

0

0

-1

0

-1

-3

-1

-2

-2

0

~2

-1

-1

0

-2

_1

-1

0

0

0

-1

0

-1

-3

-2

-1

-2

0CM _2

-1

-1

-2

-1

-1

.1/ See Section 2.1.4. for design change category definitions,

100
4.4.6 Combined Effect of Additional Factors on Relative Net Benefits.

The dollar values of each factor discussed on Sections 4.4.1

through 4.4.5 have been applied to the relative net benefits from Tables

4-4 and 4-7. The relative net benefits adjusted for these factors are

shown in Table 4-11. Only the 1983 + 1984 model years combined with 0.7

secondary weight factor are included in the table.

The statistical significance remained unchanged for combined

bumper changes, and for the Front+Rear and Front bumpers of each design

change category. For Rear bumpers with facebar changes, a statistically

significant decrease in relative net benefits was found, instead of no

significant difference for the unadjusted data. The relative net benefit

of the rear bumpers for the other design change categories was still not

statistically significant.

Taking into account all possible factors does not change the

finding that there was no statistically significant difference between

changed and unchanged bumpers, based on 14 of 15 comparisons in Table

4-11. The adjusted relative net benefit is either -$2 (unrepaired damage

valued at 50%) or +$1 (with 75% of damage repaired). The 1982 FRIA value

(in 1984 dollars) is $15. However, none of these values indicate any

significant difference between changed and unchanged bumper designs.

101
TABLE 4-11

RELATIVE NET BENEFIT ADJUSTED FOR ADDITIONAL FACTORS

Nee Differences (Benefits less Costs)

Between Cr.anged and Unchanged Bumper Systems

All Changes Combined and By Design Change Categories 2/

(1984 Dollars and 0.7 secondary Weight Factor) 3/

1983+1984 Vs. 1981/82

ADJUSTMENTS

DESIGN CHANGS

CATEGORY 2/

All Design Changes Combined

FRONT + REAR

FRONT

REAR

FRONT + REAR

Facebar

Structural

Energy Absorber

Structural + Energy Absorber

FRONT

Facebar

Structural

Energy Absorber

Structural + Energy Absorber

REAR

Facebar

Structural

Energy Absorber

Structural + Energy Absorber

Relative

Net

Benefit

+8

+14

-6

-42

-25

+65

-9

-11

-19

+33

+3

-31

-6

+32

-12

Delay &

Inconven.

-4

-2

-2

-4

-4

-4

-4

-2

-2

-2

-2

-2

-2

-2

-2

Insurance

Costs

-10

-6

-4

-10

-10

-10

-10

-6

-6

-6

-6

-4

-4

-4

-4

Unrepaired

Damage

^50% / 975%

-6/-3

Q/-1

-6/-2

-11/-6

-12/-6

+ 1/ + 1

-7/-3

-3/-2

-7/-4

+5/+2

-2/-1

-8/-4

-5/-2

-4/-1

-5/-2

High Speed

Collisions

+4

+ 3

+ 1

+4

+4

+4

+4

+3

+3

+ 3

+3

+ 1

+1

+1

+1

Interest

Savings

+2

+ 1

+1

+1

+3

+2

+2

0

+2

0

+1

+1

+1

+2

+1

TOTAL

ADJUSTMENT

-14/-11

-4/-S

-10/-6

-20/-15

-19/-13

-7/-7

-15/-11

-8/-7

-10/-7

0/-3

-6/-5

-12/-8

-9/-6

-7/-4

-9/-6

Adjusted

Relative

Net

Benefit

-6/-3

+10/+9

-16/-12

-62/-57

-44/-38

+58/+5S

-24/-20

-19/-18

-29/-26

+ 33/+30

-3/-2

-43/-39

-15/-14

+25/+36

-21/-18

Conf. 4/

Interval

- or +

54

33

24

54

52

149

64

43

41

135

39

32

30

79

44

Significant

Incr. or Deer.

of Changed Bumper

Systems 5/

No Signif. Change

No Signif. Change

No Signif. Change

Signif. Decrease

No Signif. Change

No Signif. Change

No signif. change

No Signif. Change

So Signif. Change

No Signif. Change

No Signif. Change

Signif. Decrease

No Signif. Change

No Signif. Change

No signif. change

1/ See Appendix E for' Algorithm defining net benefit.

2/ See Section 2.1.4 for for explanation of design changes.

3/ See Section 4.1.5 for definition of secondary weight factor.

4/ 95 percent Confidence Level

5/ Significant >0 where HO: pl=p2 vs. HI: pl>p2, Alpha=0.05.
Appomb'x A

Title 49—Transportation

Sec.

581.4

581.5

581.6

581.7

Definitions.

Requirements.

Conditions.

Test procedures.

AUTHORITY: Sec. 103, 118, Pub. L. 89-663,

80 Stat. 718 (15 U.S.C. 1392, 1407); sec. 102,

Pub. L. 92-513, 86 Stat. 947 (15 U.S.C. 1912)

delegation of authority at 49 CFR 1.50,

unless otherwise noted.

SOURCE: 42 FR 24059, May 12, 1977, unless

otherwise noted.

PART 581— BUMPER STANDARD

Sec.

581.1 Scope.

581.2 Purpose.

581.3 Application.

§ 581.1 Scope.

This standard establishes require

ments for the Impact resistance of ve

hides in low speed front and rear colli

sions.

§ 581.2 Purpose.

The purpose of this standard is to

reduce physical damage to the front

and rear ends of a passenger motor vehicle from low speed collisions.

§581.3 Application.

This standard applies to passenger

motor vehicles other than multipurpose passenger vehicles.

6 581.4 Definitions.

All terms defined in the Motor Vehicle Information and Cost Savings Act,

Pub. L. 92-513, 15 U.S.C. 1901-1991,

are used as defined therein.

"Bumper face bar" means any com

ponent of the bumper system that

contacts the impact ridge of the pendulum test device.

§581.5 Requirements.

(a) Each vehicle shall meet the

damage criteria of SS 581.5(c)(l)

through 581.5(c)(9) when impacted by

a pendulum-type test device in accordance with the procedures of § 581.7(b),

under the conditions of § 581.6, at an

impact speed of 1.5 m.p.h., and when

impacted by a pendulum-type test

device in accordance with the procedures of §581.f(a) at 2.5 m.p.h., followed by an impact into a fixed collision barrier that is perpendicular to

the line of travel of the vehicle, while

traveling longitudinally forward, then

longitudinally rearward, under the

conditions of § 581.6, at 2.5 m.p.h.

(b) [Reserved]

103
Chap. V—Nat. Highway Traffic Safety Admin., Dspf. of Trans. §581.6

(c) Protective criteria. (1) Each lamp

or reflective device except license

plate lamps shall be free of cracks and

shall comply with applicable visibility

requirements of S4.3.1.1 of Standard

No. 108 (§571.108 of this part). The

aim of each headlamp shall be adjustable to within the beam aim Inspection

limits specified in Table 2 of SAE Recommended Practice J599b. July 1970,

measured with a mechanical aimer

conforming to the requirements of

SAE Standard J602a, July 1970.

(2) The vehicle's hood, trunk, and

doors shall operate in the normal

manner.

(3) The vehicle's fuel and cooling

systems shall have no leaks or constricted fluid passages and all sealing

devices and caps shall operate in the

normal manner.

<4) The vehicle's exhaust system

shall have no leaks or constrictions.

(5) The vehicle's propulsion, suspension, steering, and braking systems

shall remain in adjustment and shall

operate in the normal manner.

(6) A pressure vessel used to absorb

impact energy in an exterior protection system by the accumulation of

gas pressure or hydraulic pressure

shall not suffer loss of gas or fluid accompanied by separation of fragments

from the vessel.

(7) The vehicle shall not touch the

test device, except on the impact ridge

shown in Figures 1 and 2, with a force

that exceeds 2000 pounds on the combined surfaces of Planes A and B of

the test device.

(8) The exterior surfaces shall have

no separations of surface materials,

paint, polymeric coatings, or other

covering materials from the surface to

which they are bonded, and no permanent deviations from their original

contours 30 minutes after completion

of each pendulum and barrier impact,

except where such damage occurs to

the bumper face bar and the components and associated fasteners that directly attach the bumper face bar to

the chassis frame.

(9) Except as provided in

§581.5(0(8), there shall be no breakage or release of fasteners or joints.

142 FR 24059, May 12, 1877, as amended at

42 PR 38900. Aug. 1, 1977; 43 FK 40233,

Sept. 11, 1978: 47 PR 21837, May 20, 1882)

§581.6 Conditions.

The vehicle shall meet the requirements of § 581.5 under the following

conditions.

(a) General. (1) The vehicle is at unloaded vehicle weight.

(2) The front wheels are in the

straight ahead position.

(3) Tires are inflated to the vehicle

manufacturer's recommended pressure

for the specified loading condition.

(4) Brakes are disengaged and the

transmission is in neutral.

(5) Trailer hitches, license plate

brackets, and headlamp washers are

removed from the vehicle. Running

lights, fog lamps, and equipment

mounted on the bumper face bar are

removed from the vehicle if they are

optional equipment.

(b) Pendulum test conditioiis. The

following conditions apply to the pendulum test procedures of §881.7 (a)

and (b).

(1) The test device consists of a

block with one side contoured as specified in Figure 1 and Figure 2 with the

impact ridge made of A1S1 4130 steel

hardened to 34 Rockwell "C." The

impact ridge and the surfaces in

Planes A and B of the test device are

finished with a surface roughness of

32 as specified by SAE Recommended

Practice J449A, June 1963. From the

point of release of the device until the

onset of rebound, the pendulum suspension system holds Plane A vertical,

with the arc described by any point on

the impact line lying in a vertical

plane (for § 581.7(a), longitudinal; for

! 581.7(b), at an angle of 30° to a vertical longitudinal plane) and having a

constant radius of not less than 11

feet.

(2) With Plane A vertical, the impact

line shown in Figures 1 and 2 is horizontal at the same height as the test

device's center of percussion.

(3) The effective impacting mass of

the test device is equal to the mass of

the tested vehicle.

(4) When impacted by the test

device, the vehicle is at rest on a level

rigid concrete surface.

(c) Barrier test condition. At the

onset of a barrier impact, the vehicle's

engine is operating at idling speed in

accordance with the manufacturer's

1 0 l\
§581.7

specifications. Vehicle systems that

are not necessary to the movement of

the vehicle are not operating during

impact.

(Sec. 102, Pub. L. 92-513, 86 Stat. 947 (15

U.S.C. 1912); sees. 103, 119, Pub. L. 89-563,

80 Stat. 718 (15 U.S.C. 1392, 1407); delegation of authority at 49 CFR 1.50 and 501.7)

[42 FR 24059, May 12, 1977, as amended at

42 FR 38909, Aug. 1, 1977; 48 FR 43331,

Sept. 23, 19831

e 581.7 Test procedures.

(a) Longitudinal impact test procedures. (1) Impact the vehicle's front

surface and its rear surface two times

each with the impact line at any

height from 16 to 20 inches, inclusive,

in accordance with the following procedure.

(2) For impacts at a height of 20

inches, place the test device shown in

Figure 1 so that Plane A is vertical

and the impact line is horizontal at

the specified height.

(3) For impacts at a height between

20 inches and 16 inches, place the test

device shown in Figure 2 so that Plane

A is vertical and the impact line is horizontal at a height within the range.

(4) For each impact, position the test

device so that the impact line is at

least 2 inches apart in vertical direction from its position in any prior

impact, unless the midpoint of the

impact line with respect to the vehicle

is to be more than 12 inches apart laterally from its position In any prior

impact.

(5) For each impact, align the vehicle so that it touches, but does not

move, the test device, with the vehicle's longitudinal centerline perpendicular to the plane that includes Plane

A of the test device and with the test

device inboard of the vehicle corner

test positions specified in § 581.7(b).

(6) Move the test device away from

the vehicle, then release it to impact

the vehicle.

(7) Perform the impacts at intervals

of not less than 30 minutes.

(b) Corner impact test procedure. (1)

Impact a front corner and a rear

corner of the vehicle one each with

the impact line at a height of 20

inches and impact the other front

corner and the other rear corner once

each with the impact line at any

Title 49—Transportation

height from 16 to 20 inches, inclusive,

in accordance with the following procedure.

(2) For an impact at a height of 20

inches, place the test device shown in

Figure 1 so that Plane A is vertical

and the impact line is horizontal at

the specified height.

(3) For an impact at a height between 16 inches and 20 inches, place

the test device shown in Figure 2 so

that Plane A is vertical and the impact

line is horizontal at a height within

the range.

(4) Align the vehicle so that a vehicle corner touches, but does not move,

the lateral center of the test device

with Plane A of the test device forming an angle of 60 degrees with a vertical longitudinal plane.

(5) Move the test device away from

the vehicle, then release it to impact

the vehicle.

(6) Perform the Impact at intervals

of not less than 30 minutes.

oirnV-i r ^

U M V, X

105
PART 581-BUMPER STANDARD

(Docket No. 74-11; Notice 12; Dock*} No. 73-1®; Notlca 9)

§ 581.1 Scops. This standard establishes requirements for the impact resistance of vehicles

in low speed front and rear collisions.

S 581.2 Purpose. The purpose of this standard is to reduce physical damage to the front

and rear ends of a passenger motor vehicle from

low speed collisions.

§ 581.3 Application. This standard applies to

passenger motor vehicles other than multipurpose passenger vehicles.

§ 581.4 Definitions. All terms defined in the

Motor Vehicle Information and Cost Savings

Act, P.L. 92-513, 15 U.S.C. 1901-1991, are used

as defined therein.

"Bumper face bar" means any component of

the bumper system that contacts the impact ridge

of the pendulum test device.

§ 581.5 Requirements.

(a) |Each vehicle shall meet the damage criteria

of S§ 581.5(c) (1) through 581.5 (c) (9) when impacted by a pendulum-type test device in accordance with the procedures of § 581.7(b), under the

conditions of % 581.6, at an impact speed of 1.5

m.p.h., and when impacted by a pendulum-type

test device in accordance with the procedures of

S 581.7(a) at 2.5 m.p.h., followed by an impact into

a fixed collision barrier that is perpendicular to the

line of travel of the vehicle, while traveling longitudinally forward, then longitudinally rearward,

under the conditions of % 581.6, at 2.5 m.p.h." (47

F.R. 2182-May 20,1982. Effective: July 4,1982)1

(b) [Reserved.!

(Rev. 7/4/82)

(c) Protective criteria.

(1) Each lamp or reflective device except

license plate lamps shall be free of cracks and

shall comply with applicable visibility requirements of S4.3.1.1 of Standard No. 108 (S 571.108

of this part). The aim of each headlamp shall

be adjustable to within the beam aim inspection

limits specified in Table 2 of SAE Recommended

Practice J599b, July 1970, measured with a mechanical aimer conforming to the requirements

of SAE Standard J602a, July 1970.

(2) The vehicle's hood, trunk, and doors

shall operate in the normal manner.

(3) The veliicle's fuel and cooling systems

shall have no leaks or constricted fluid passages

and all sealing devices and caps shall operate in

the normal manner.

(4) The vehicles' exhaust system shall have

no leaks or constrictions.

(5) The vehicle's propulsion, suspension,

steering, and braking systems shall remain in

adjustment and shall operate in the normal

manner.

(6) A pressure vessel used to absorb impact

energy in an exterior protection system by the

accumulation of gas pressure or hydraulic pressure shall not suffer loss of gas or fluid accompanied by separation of fragments from the

vessel.

(7) The vehicle shall not touch the test device, except on the impact ridge shown in Figures

1 and 2, with a force that exceeds 2000 pounds

on the combined surfaces of Planes A and B of

the test device.

PART 581-1

106
(8) The exterior surfaces shall have no separations of surface materials, paint, polymeric coatings, or other covering materials from the surface

to which they are bonded, and no permanent deviations from their original contours 30 minutes after

completion of each pendulum and barrier impact,

except where such damage occurs to the bumper

face bar and the components and associated fasteners that directly attach the bumper face bar to

the chassis frame.

(9) Except as provided in $ 581.5(c) (8),

there shall be no breakage or release of fasteners

or joints.

(10) Reserved.

(R*V. B/23/B3)

(11) Reserved.

§ 581.6 Conditions. The vehicle shall meet

the requirements of $ 581.5 under the following

conditions:

(a) General.

(1) The vehicle is at unloaded vehicle

weight.

(2) The front wheels are in the straight

ahead position.

(3) Tires are inflated to the vehicle manufacturer's recommended pressure for the specified

loading condition.

(4) Brakes are disengaged and the transmission is in neutral.

(5) [Trailer hitches, license plate brackets, and

headlamp washers are removed from the vehicle.

Running lights, fog lamps, and equipment mounted

on the bumper face bar are removed from the vehicle if they are optional equipment. (48 F.R.

43331—September 23, 1983. Effective: September

23, 1983)1

(b) Pendulum test conditions. The following

conditions apply to the pendulum test procedures

of S 581.7(a) and S 581.7(b):

(1) The test device consists of a block with

one side contoured as specified in Figure 1 and

Figure 2 with the impact ridge made of AI SI

4130 steel hardened to 34 Rockwell "C." The

impact ridge and the surfaces in Planes A and B

of the test device are finished with a surface

roughness of 32 as specified by SAE Recommended Practice J449A, June 1963. From the

point of release of the device until the onset of

rebound, the pendulum suspension system holds

Plane A vertical, with the arc described by any

point on the impact line lying in a vertical plane

PART 581-2

107
(for § 581.7(a), longitudinal; for § 581.7(b), at

an angle of 30° to a vertical longitudinal plane)

and having a constant radius of not less than

11 feet.

(2) With Plane A vertical, the impact line

shown in Figures 1 and 2 is horizontal at the

same height as the test device's center of percussion.

(3) The effective impacting mass of the test

device is equal to the mass of the tested vehicle.

(4) When impacted by the test device, the

vehicle is at rest on a level rigid concrete surface.

(c) Barrier Test Condition. At the onset of a

barrier impact, the vehicle's engine is operating

at idling speed in accordance with the manufacturer's specification. Vehicle systems that are not

necessary to the movement of the vehicle are not

operating during impact.

§ 581.7 Test Procedures.

(a) Longitudinal Impact Test Procedures.

(1) Impact the vehicle's front surface and

its rear surface two times each with the impact

line at any height from 16 to 20 inches, inclusive,

in accordance with the following procedure.

(2) For impacts at aheight of 20 inches,

place the test device shown in Figure 1 so that

Plane A is vertical and the impact line is horizontal at the specified height.

(3) For impacts at a height between 20

inches and 16 inches, place the test device shown

in Figure 2 so that Plane A is vertical and the

impact line is horizontal at a height within the

range.

(4) For each impact, position the test device so that the impact line is at least 2 inches

apart in vertical direction from its position in

any prior impact, unless the midpoint of the

impact line with respect to the vehicle is to be

more than 12 inches apart laterally from its

position in any prior impact.

(5) For each impact, align the vehicle so

that it touches, but does not move, the test device, with the vehicle's longitudinal centerline

perpendicular to the plane that includes Plane A

of the test device and with the test device inboard of the vehicle corner test positions specified in $ 581.7(b).

(6) Move the test device away from the vehicle, then release it to impact the vehicle.

(7) Perform the impacts at intervals of not

less than 30 minutes.

(b) Corner impact test procedure.

(1) Impact a front corner and a rear corner

of the vehicle once each with the impact line at

a height of 20 inches and impact the other front

corner and the other rear corner once each with

the impact line at any height from 16 to 20

inches, inclusive, in accordance with the following procedure.

(2) For an impact at a height of 20 inches,

place the test device shown in Figure 1 so that

Plane A is vertical and the impact line is horizontal at the specified height.

(3) For an impact at a height between 16

inches and 20 inches, place the test device shown

in Figure 2 so that Plane A is vertical and the

impact line is horizontal at a height within the

range.

(4) Align the vehicle so that a vehicle corner touches, but does not move, the lateral center

of the test device with Plane A of the test device

forming an angle of 60 degrees with a vertical

longitudinal plane.

(5) Move the test device away from the vehicle, then release it to impact the vehicle.

(6) Perform the impacts at intervals of not

less than 30 minutes.

41 F.R. 9346

March 4,1976

PART 581-3

1 0 8
APPENDIX B

Models Studied, sales and Market Share

MAKE/MODELS

TOYOTA CELICA

PONTIAC GRAND PRIX

VW RABBIT

BUICK REGAL

BUICK CENTURY

FORD THUNDERBIRD/MERCURY COUGAR

FORD EXP

OLDS CUTLASS SUPREME

MERCURY MARQUIS-GRAND MARQUIS

OLDS CUTLASS CIERA

AMC/RENAULT ALLIANCE

DATSUN 280ZX-300ZX

FORD LTD-CROWN VICTORIA

FORD TEMPO/MERCURY TOPAZ

FORD MUSTANG/MERCURY CAPRI

OLDS 88/98

FORD ESCORT/MERCURY LYNX

BUICK SKYLARK

AMC/RENAULT ENCORE

DATSUN 200SX

MAZDA GLC

FORD GRANADA/MERC COUGAR-FORD LTD/MERC MARQUIS

PONTIAC BONNEVILLE

CADILLAC DEVILLE

TOYOTA TERCEL

CHEVROLET CAVALIER

DATSUN 310-NISSAN PULSAR

BMW 320i-320i/318i-318i

VOLVO 240/260

PONTIAC J2000

DATSUN 210-NISSAN SENTRA

TOYOTA COROLLA

CHEVROLET IMPALA/CAPRICE

BUICK ELECTRA/LE SABRE

CHEVROLET CAMARO

CHEVROLET CHEVETTE

CHEVROLET CITATION-CITATION II

PONTIAC FIREBIRD

CHEVROLET CELEBRITY

CHEVROLET MONTE CARLO

OLDS FIRENZA

BUICK SKYHAWK

PONTIAC 1000

OLDS OMEGA

CHRYSLER E CLASS

CHRYSLER LE BARON "K"

CHRYSLER NEW YORKER E

DODGE 600-600 4DR

PLY HORI/DGE OMNI 2DR-PLY TURISMO/TC3/DGB CHGR/024

PLYMOUTH HORI/DODGE OMNI 4DR

PLYMOUTH RELIANT/DODGE ARIES

HONDA CIVIC

HONDA ACCORD/LX

DODGE 400-400/600 COUPE

PONTIAC PHOENIX

FORD FAIRMONT/MERCURY ZEPHYR

CHEVROLET MALIBU

Model

Year

1981

120025

106344

179635

332005

0

454022

61638

62800

78150

241498

268568

432705

200460

77062

62195

174994

19819

150915

121328

77980

31902

21817

159939

241603

184992

158194

123138

453982

300184

70899

157115

70194

147918

36311

151415

128116

410163

154698

172557

127869

277809

226727

Market

Share

Percent

1.33

1.20

2.00

3.69

0.00

0.00

0.00

5.05

0.68

0.00

0.00

0.70

0.87

0.00

2.68

2.98

4.81

2.23

0.00

0.86

0.69

1.94

0.22

1.68

1.35

0.00

0.87

0.35

0.24

0.00

1.78

2.68

2.06

1.76

1.37

5.05

3.34

0.79

0.00

1.75

0.00

0.00

0.78

1.64

0.00

0.40

0.00

0.00

1.68

1.42

4.56

1.72

1.92

0.00

1.42

3.09

2.52

Model

Year

1982

103879

80650

102664

225418

102965

6692

194337

77157

101320

63791

41943

166552

265178

418531

144560

76024

62195

177273

80440

137600

121328

195024

77950

31902

39288

118859

160077

241630

188178

175052

178808

243463

165647

116364

92314

92391

30108

47918

44469

77469

82003

85356

287596

154698

172557

34340

49165

166831

116125

Market

Share

1.34

1.04

1.33

2.91

1.33

0.00

0.09

2.51

1.00

1.31

0.00

0.82

0.54

0.00

2.15

3.42

5.40

1.87

0.00

0.98

0.80

2.29

1.04

1.78

1.57

2.52

1.01

0.41

0.51

1.53

2.07

3.12

2.43

2.26

2.31

3.14

2.14

1.50

1.19

1.19

0.39

0.62

0.57

1.00

0.00

0.00

0.00

0.00

1.06

1.10

3.71

2.00

2.23

0.44

0.63

2.15

1.50

Model

Year

1983

119140

87026

83150

233016

134804

164614

26471

314473

98341

169939

124687

68651

124650

141620

332398

403862

107363

37102

55418

200505

82002

173086

151052

216297

56180

34681

40783

75509

212793

144860

226750

216503

175004

183970

116460

93378

155953

98865

43042

69946

36286

56210

36610

81478

33494

30042

82317

96704

286409

139169

177219

31947

99295

107761

Market

Share

1.3/

1.00

0.96

2.68

1.5b

1.89

0.30

3.62

1.13

1.95

1.43

0.79

1.4.!

0.00

1.6J

3.8.

4.64

1.2J

0.00

0.4J

0.64

2.31

0.94

1.99

1.74

2.49

0.6b

0.40

0.47

0.87

2.45

1.67

2.61

2.49

2.01

2.12

1.34

1.07

1.79

1.14

0.50

0.80

0.44

0.65

0.42

0.94

0.39

0.35

0.95

1.11

3.29

1.60

2.04

0.37

0.00

1.14

1.24

Model

Year

1984

90784

23953

116585

224754

219858

301722

23016

309124

90341

280839

121015

75968

86084

273392

162122

370701

397858

111211

87609

63914

51906

321560

29269

160599

108889

462612

39131

30134

90592

169290

195355

159323

276492

228901

261592

243904

102205

128304

309288

136778

82475

145393

55083

52986

36494

111808

69746

36864

51799

290396

337947

161123

139152

23443

22847

106036

107761

Market

Share

0.B6

0.23

1.11

2.13

2.09

2.86

0.22

2.93

0.86

2.07

1. 15

0.72

0.82

2.60

1.54

3.').:

3. 78

1.0b

0.U3

0.61

0.49

3.05

0.2b

1.52

1.03

4. 39

0.3'

0.29

O.Hu

1.61

1.85

1.51

2.62

2.17

2.4«

2.32

0.47

1.2.

2.94

1.30

0.7b

1.3o

0.5.

0.5J

0.35

1.06

0.66

0.35

0.4 9

2.7 6

3.21

1.53

1.32

0.22

0.22

1.01

1.02

109
APPENDIX C

Nameplates included in 1981 thru 1984 Comparisons

1981/1982

TOYOTA CELICA

PONTIAC GRAND PRIX

VW RABBIT

BUICK REGAL

BUICK CENTURYU982 ONLY)

FORD EXP(1982 ONLY)

OLDS CUTLASS SUPREME

MERCURY MARQUIS

OLDS CIERA(1982 ONLY)

DATSUN 280 ZX

FORD LTD

FORD MUSTANG/MERC CAPRI

OLDS 88/98

FORD ESCORT/MERCURY LYNX

BUICK SKYLARK

DATSUN 200SX

MAZDA GLC

FORD GRANADA/MERC COUGAR

PONTIAC BONNEVILLE

CADILLAC DEVILLE

TOYOTA TERCEL

CHEV CAVALIER!1982 ONLY)

DATSUN 310

BMW 320i

VOLVO 240/260

PONTIAC J2000U982 ONLY)

DATSUN 210

TOYOTA COROLLA

CHEV IMP ALA/CAPRICE

BUICK ELECTRA/LE SABRE

CHEVROLET CAMARO

CHEVROLET CHEVETTE

CHEV CITATION

PONTIAC FIREBIRD

CHEV CELEBRITY(1982 ONLY)

CHEVROLET MONTE CARLO

OLDS FIRENZA(1982 ONLY)

BUICK SKYHAWK11982 ONLY)

PONTIAC 1000

OLDS OMEGA

CHRY LE BARON(1981 ONLY)

PLY HORI/DGE OMNI 2DR

PLY HORI/DGE OMNI 4DR

PLY RELIANT/DGE ARIES

HONDA CIVIC

HONDA ACCORD/LX

DGE 400/600CPEU982 ONLY)

PONT PHOENIX(1982 ONLY)

FORD FAIRMONT/MERC ZEPHYR

CHEVROLET MALIBU

1983

TOYOTA CELICA

PONTIAC GRAND PRIX

VW RABBIT

BUICK REGAL

BUICK CENTURY

FORD T1BIRD/MERC. COUGAR

FORD EXP

OLDS CUTLASS SUPREME

MERCURY GRAND MARQUIS

OLDS CUTLASS CIERA

AMC/RENAULT ALLIANCE

DATSUN 280ZX

FORD CROWN VICTORIA

FORD MUSTANG/MERC CAPRI

OLDS 88/98

FORD ESCORT/MERCURY LYNX

BUICK SKYLARK

DATSUN 200SX

MAZDA GLC

FORD LTD/MERC MARQUIS

PONTIAC BONNEVILLE

CADILLAC DEVILLE

TOYOTA TERCEL

CHEVROLET CAVALIER

NISSAN PULSAR

BMW 320i/318i

VOLVO 240/260

PONTIAC J2000

NISSAN SENTRA

TOYOTA COROLLA

CHEV IMPALA/CAPRICE

BUICK ELECTRA/LE SABRE

CHEVROLET CAMARO

CHEVROLET CHEVETTE

CHEV CITATION

PONTIAC FIREBIRD

CHEVROLET CELEBRITY

CHEVROLET MONTE CARLO

OLDS FIRENZA

BUICK SKYHAWK

PONTIAC 1000

OLDS OMEGA

CHRYSLER E CLASS

CHRYSLER LE BARON "K"

CHRYSLER NEW YORKER E

DODGE 600-600 4DR

PLY HORI/DGE OMNI 2DR

PLY HORI/DGE OMNI 4DR

PLY RELIANT/DGE ARIES

HONDA CIVIC

HONDA ACCORD/LX

DGE 400/600CPE

FORD FAIRMONT/MERC ZEPHYR

CHEVROLET MALIBU

1984

TOYOTA CELICA

PONTIAC GRAND PRIX

VW RABBIT

BUICK REGAL

BUICK CENTURY

FORD T'BIRD/MERC. COUGAR

FORD EXP

OLDS CUTLASS SUPREME

MERCURY GRAND MARQUIS

OLDS CUTLASS CIERA

AMC/RENAULT ALLIANCE

NISSAN 300ZX

FORD CROWN VICTORIA

FORD TEMPO/MERCURY TOPAZ

FORD MUSTANC/MERC CAPRI

OLDS 88/98

FORD ESCORT/MERCURY LYNX

BUICK SKYLARK

AMC/RENAULT ENCORE

DATSUN 200SX

MAZDA GLC

FORD LTD/MERC MARQUIS

PONTIAC BONNEVILLE

CADILLAC DEVILLE

TOYOTA TERCEL

CHEVROLET CAVALIER

NISSAN PULSAR

BMW 318i

VOLVO 240/260

PONTIAC J2000

NISSAN SENTRA

TOYOTA COROLLA

CHEV IMPALA/CAPRICE

BUICK ELECTRA/LE SABRE

CHEVROLET CAMARO

CHEVROLET CHEVETTE

CHEV CITATION II

PONTIAC FIREBIRD

CHEVROLET CELEBRITY

CHEVROLKT MONTE CARLO

OLDS FIRENZA

BUICK SKYHAWK

PONTIAC 1000

OLDS OMEGA

CHRYSLER E CLASS

CHRYSLER LE BARON "K"

CHRYSLER NEW YORKER E

DODGE 600-600 4DR

PLY HORI/DGE OMNI 2DR

PLY HORI/DGE OMNI 4DR

PLY RELIANT/DGE ARIES

HONDA CIVIC

HONDA ACOORD/LX

DODGE 600 CPE

110
APPENDIX D

BUMPER DESIGN CHANGE CATEGORIES BY MAKE/MODEL FOR 1983, FOR 1984

1983 CHANGED MODELS 1984 CHANGED MODELS

FRONT

CITATION

FIREBIRD

SKYHAWK

CHEVETTE

T1000

MALIBU,CHEVELLE

FRONT

VOLVO!240 ETC.)

SENTRA(210/B210)

BONNEVILLE

J2000

CAMARO

CADILLAC

TERCEL

GRAN PRIX

FACEBAR

REAR

CITATION

FIREBIRD

SKYHAWK

CHEVETTE

T1000

FIRENZA

CENTURY

STRUCTURAL

REAR

VOLVO(240 ETC.)

SENTRA(210/B210)

BONNEVILLE

J2000

CAMARO

CADILLAC

TERCEL

LESABRE

ELECTRA

FRONT

FIRENZA

SKYHAWK

CHEVETTE

OMEGA

MONTE CARLO

FIREBIRD

CELEBRITY

T1000

CITATION

FRONT

LESABRE

CHEVROLET

CAVALIER

3201/3181

CADILLAC

ELECTRA

J2000

VOLVO(240 ETC)

BONNEVILLE

TERCEL

COROLLA

SENTRA(210/B210)

CAMARO

GRAN PRIX

CELICA

REAR

FIRENZA

SKYHAWK

CHEVETTE

OMEGA

MONTE CARLO

FIREBIRD

CELEBRITY

T1000

CITATION

CENTURY

REGAL

REAR

LESABRE

CHEVROLET

CAVALIER

3201/3181

CADILLAC

ELECTRA

J2000

VOLVO(240 ETC)

BONNEVILLE

TERCEL

COROLLA

SENTRA(210/B210)

CAMARO

ENERGY ABSORBER

FRONT

400

LEBARON

600

E CLASS

OMNI/SHELBY/CHGR

NEW YORKER

REAR

LEBARON

600

E CLASS

OMNI/SHELBY/CHARGER

NEW YORKER

STRUCTURAL AND ENERGY

FRONT

E CLASS

LE BARON(K CAR)

NEW YORKER

600

REAR

E CLASS

LE BARON(K CAR)

NEW YORKER

600

FRONT REAR

CIVIC

RELIANT

OMNI

ARIES

ACCORD

HORIZON

400

CIVIC

RELIANT

OMNI

ARIES

ACCORD

HORIZON

FRONT

OMNI/SHELBY/CHGR

HORIZON

RELIANT

ARIES

CIVIC

ACCORD

RABBIT

REAR

OMNI/SHELBY/CHARGER

HORIZON

RELIANT

ARIES

CIVIC

ACCORD

1 1 I
APPENDIX E

MODEL FOR CALCULATING NET BENEFITS

Gross benefits are measured in lifetime repair costs resulting from

low-speed bumper involved collisions that occur over a cars life. The two

primary sources of information used to calculate gross benefits are a

national driver survey and analysis of State Farm insurance claim data.

The general equation for gross lifetime benefits discounted over a ten

year car life using average annual mileage, vehicle survivability factors

and a 10 percent discount rate is:

B- LCLKO.C.P.) + (N.I.K.)] CDF]

where: B= discounted gross lifetime benefits (Tables 4-2, 4-5)

L= average car life = 10 years

U= The low speed collision incident rate for cars in which no

insurance claim is filed (driver's survey found this

rate for 1981 thru 1984 model year cars to be 12.25 percent)

D= The damage frequency of cars per unclaimed collision (Tables

3-1, 3-2, 3-3).

i= subscript refers to data on a particular model year, bumper

design category, and end of car involved in collision.

C<= The average cost to repair damage per car in unclaimed

collisions (Table 3-4).

1 12
P= The proportion of cars in unreported collisions that were

struck in the front or rear (ratio).

N= The rate of property damage insurance claims per insured

vehicle year. This is the product of HLDI data collision

claims per insured vehicle year, multiplied by the ratio of

all property damage claims to collision claims from State

Farm data. Nine to 10 percent of cars have a collision claim

annually and another 3 percent have property damage liability

claims. The overall average for 1981 through 1984 models in

the first year was 12.3%.

1= The proportion of property damage insurance claims involving

the bumper to all property damage insurance claims (ratio).

(Tables 3-8, 3-10).

K= The average cost to repair damage in insurance claims involving the bumper. (Tables 3-9, 3-11).

DF= The discount factor for 10 year car life at 10 percent

discountable 4-1) =.7393.

The Gross Costs, including lifetime fuel discounted costs and secondary

weight considerations resulting in bumpers designed to meet a particular

performance standard, are shown in the following equation:

C- BC. + BW. [(FXDGX1+S) ] + (BW.)(S)(BS)

113
Where:

C= Gross cost of bumper systems, secondary weight and fuel

cost discounted over a car's ten year life, for operating

a passenger car considering the weight of the bumper systems

and secondary weight.

BC= Cost of the energy management portion of a bumper system

i= Subscript refers to data on particular Model year, bumper

design category and end of car.

BW= Weight of energy management portion of a bumper system

F= Number of gallons used per pound of car to operate it over a

ten year life (for this study F=1.25 gal/#)

To calculate the lifetime fuel use per pound of vehicle

weight, the ratio of vehicle curb weight and fuel economies

are considered as follows:

0 ft Fuel Economy Car 2 = (curb weight car/curb car 2) ' x

fuel economy of car 1

where

Curb weight car 1 - 2701# (curb weight of 1983/1984

changed

Models plus reduction in

bumper weight --12#)

114
Curb weight car 2 = 2689# (average curb weight of

1983/1984 models with

changed bumpers)

Fuel Economy car 1 = 27.041 mpg (average EPA fuel

economy 1983/1984 models

with changed bumpers)

and

Fuel economy car 2 = 27.137 mpg

Reduce both fuel economy values by 15% to obtain actual

on-road fuel economy.

Car 1 = 22.985 mpg

Car 2 » 23.067 mpg

Lifetime fuel use (10-year life - 95,345miles)

Car 1 - 95345/22.985 = 4148

Car 2 . 95345/23.067 . 4133

1 1

 r>
Difference in fuel use - 4148-4133 - 15 gallons

Difference in vehicle weight - 12 pounds

Ratio of gallons/pound - 15/12 « 1.25 gal/#

DG- discounted cost of fuel for a ten year car life based on 10

percent discount rate, current fuel price per gallon

projection, and using the same mileage and vehicle survival

values as for the repair cost discount factor (DF). For

this study DG- .83513.

FUEL PRICE DISCOUNTED OVER 10 YEAR LIFE 1/

A.

VEHICLE

AGE

(YEARS)

1

2

3

4

5

6

7

8

9

10

TOTAL

B.

AVERAGE ANNUAL

VEHICLE MILES

TRAVELED

14535

13924

12846

11378

10749

10119

9490

8860

8231

7601

C.

SURVIVAL

PROBABILITY

1.000

0.993

0.982

0.964

0.935

0.892

0.831

0.753

0.662

0.568

D.

(B*C)

14535

13827

12615

10968

10050

9026

7886

6672

5449

4317

95345

E.

PRESENT

WORTH

?ACTOR(10%)

1.000 0

0.9091

0.8264

0.7513

0.6830

0.6209

0.5645

0.5132

0.4665

0.4241

P.

(D*B)

14535

12570

10425

8241

6864

5604

4452

3424

2542

1831

70487

DISCOUNT FACTOR* 79625/95345- .83513

G.

FUEL

PRICE

(1984 $)

I

k

i

i

I

I

t

i

i

<

i

i

i

4

<

(

t

11.25

11.20

11.01

11.02

11.02

ill.06

Jl.12

11.18

il.23

il.28

H.

(P*G)

18169

15084

10529

8405

7001

5940

4986

4040

3127

2344

79625

1/ See Section 4.1.7 for discussion of average car life.

116
S» secondary weight factor values of 0.00, 0.70 and 1.00 were

used in this study. That is, for every pound of bumper

weight an additional 0, .7, or 1 pound of material was added

to weight-related vehicle parts (e.g. shock absorbers)

BS= Cost per pound of secondary weight. For this study, a cost

of 66#/lb of secondary weight was used. This represents

material and overhead cost/pound in 1984 dollars.

The difference in gross benefits, gross costs and net benefits between

cars with changed bumper designs and cars with unchanged bumper designs is

based on the following general alogarithm.

T " [P(C83, 84) ~P(c82, 82)] "P U83, 84) "P(U81, 82)]

where:

T = True difference in parameter

P(c83 84) = Parameter for 1983 and 1984 models with changed bumper

designs

Pc81 82) = Parameter f°r 1983 and 1984 models that are

predecessors of of 1983 and 1984 models with changed

bumpers

117
PU83 84)

 = Parameter f°r 1983 and 1984 models with unchanged

bumper design

PU81 82) = Parameter f°r 1981 ancl ig82 models that are predecessors

of 1983 and 1984 models with unchanged bumpers

The above alogarithm is two-fold. First, the difference between the 1983,

1984 model and its direct 1981, 1982 predecessor is determined; second,

the difference between the 1983, 1984 unchanged models and their

predecessors is deducted from the difference found for the changed models

with their predecessors models. The second step uses the unchanged 83, 84

models as a control group and helps remove any influences that may have

affected the 1983, 1984 model years differently from the 1981, 1982

models, regardless of bumper design such as weather, economic conditions

etc.

To determine the net benefit of cars with changed bumpers compared to cars

with unchanged bumpers, the true difference in gross benefits and gross

costs are first determined using the general alogarithm and then these

differences are subtracted from each other as follows:

Net Benefit - [Delta B (changed ) - Delta B (unchanged) ]

-

 CDelta C(changed) " Delta C(unchanged)]

118
where:

Delta B(changed)

Delta B(unchanged)1

Delta C(changed)

Delta D(unchanged)1

discounted gross benefit of 1983, 1984

cars with changed bumpers minus the

discounted gross benefit of 1981, 1982

predecessor models of those 83,84 cars

with changed bumpers,

discounted gross benefits of 1983, 1984

cars with unchanged bumpers minus the?

discounted gross benefit of 1981, 1982

predecessor models of those 83,84 cars

with unchanged bumpers,

gross cost of changed 1983, 1984 bumper

systems minus the gross cost of 1981,

1982 predecessor bumper systems,

gross cost of unchanged 1983, 1984 bumper

systems minus the gross cost of 1981,

1982 predecessor bumper systems.

] 19
APPENDIX F

DISCOUNT CALCULATION PROCEDURE

Future benefits are discounted to the base calendar year 1984

(end of year). A 1984 model year car, for example, is considered to be

new with ten years to go for discounting purposes. Likewise, a 1981 model

will have accumulated three "historical" years through calendar year 1984

and have seven "future" years over which benefits are still to be obtained.

To calculate discounted future benefits, a discount rate of 10

percent is used [15]. Discount factors to be applied in the calculation

are given in Table F-l below:

TABLE F-l

Discount Factors for a 10 Percent Rate

Year: 1 2 3 4 5 6 7 8 9 10

Factor: 1.000 0.909 0.826 0.751 0.683 0.621 0.564 0.513 0.467 0.424

1 2 0
The expression for discounted gross benefits is as follows:

B

B(discounted) =M

Y=H Y-10

A(Y) + A(Y) x S(Y-H)

Y-l Y-10

where:

B= The gross incremental benefit of post-standard (as

modified in 1982) changed bumper system in 1984 dollars.

M- Lifetime vehicle miles travelled.

A* Annual miles travelled over a car's ten year life.

Y- Year of car life, 1 through 10.

H= Number of "historical" years - the number of a years a

car model has been on the road through the base year for

discounting.

S= Discount factor at a 10 percent rate, (Table F-l).

121
REFERENCES

1. Abramson, P.A. and Yedlin, M. "Analysis of 1981 and 1982 Insurance

Claims to Determine Effect of 1981 and 1982 Bumpers on Crash Damage."

National Technical Information Service, Springfield Virginia, 1984.

2. Abramson, P.A. and Yedlin, M. "Analysis of 1983 Insurance Claim to

Determine Effect of 1983 Bumpers on Crash Damage." National Technical

Information Service, Springfield, Virginia, 1986.

3. Abramson, P.A. and Yedlin, M. "Analysis of 1984 Insurance Claims to

Determine Effect of 1984 Bumpers on Crash Damage." National Technical

Information Service, Springfield, Virginia, 1986.

4. Code of Federal Regulations, Title 49, Standard No. 215 - Passenger

Cars, Government Printing Office, Washington, 1981, Part 571.

5. Federal Register. Volume 46, No. 33, February 19, 1981, pp

13193-13198. Executive Order 12291 - Federal Regulation.

6. Federal Register. Volume 46, No. 190, October 1, 1981 pp 48262-48272.

Federal Motor Vehicle Safety Standards; Bumper Standard, Notice of

Proposed Rulemaking; Announcement of Public Hearing.

7. Federal Register. Volume 47, No.98, May 20, 1982 pp 21820 - 21840,

Bumper Standard, Final Rule, 49 CFR Part 581.

8. Federal Register. Volume 50, January 4, 1985, p 1036,

Executive Order 12498 - Regulatory Program.

9. "Final Regulatory Impact Analysis - Part 581 Bumper Standard."

National Highway Traffic Safety Administration, Washington, 1982.

10. LaHeist, W. G. and Ichter, K.D. "Evaluation of the Bumper Standard."

National Technical information Service, Springfield, Virginia, 1981.

(DOT HS-805-866).

11. Ludtke, N.F. and Cowie, G.O. " Cost Estimates of Post-Standard

Bumpers for Cost Evaluation of the 1982 Part 581 Bumper Standard and

Cost Estimates of Post-Standard (1983 and 1984 Model Year) Bumpers for

Cost Evaluation of the 1982 Bumper Standard." National Technical

Information Service, Springfield, Virginia, 1984. (DOT HS-806-610)

123
12. Ludtke, N.F. and Cowie, G.O. "Cost Estimates of 1985 Model Year (and

Selected Other Model Years) Bumpers for Monitoring Costs of the 1982

Part 581 Bumper Standard." National Technical Information Service,

Springfield, Virginia, 1986.

13 The Motor Vehicle Information and Cost Savings Act. Public Law

92-513, 15 United States Code 1901-1990.

14 The National Traffic and Motor Vehicle Safety Act of 1966. Public Law

89-563, as amended, 15 United States Code 1381-1431.

15 Office of Management and Budget, "Discount Ratio to be Used in

Evaluating Time Distributed Costs and Benefits." Circular A-94,

Washington, D.C . March 27, 1972.

16. "Preliminary Regulatory Impact Analysis - Bumper Standard Part 581."

National Highway Traffic Safety Administration, Washington, 1981,

17. Zdep, S.M. and Kilkenny, M.J. "Driver Survey of Low-Speed,

Bumper-Involved Collisions." National Technical Information Service,

Springfield, Virginia, 1986.

124