U.S. Department of 

Transportation

Federal Railroad 

Administration

Effect of Dynamic Envelope Pavement Markings 

on Vehicle Driver Behavior at a Highway-Rail 

Grade Crossing

Office of Research

and Development

Washington, DC 20590

DOT/FRA/ORD-14/04 Final Report

April 2014
NOTICE

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April 2014

3. REPORT TYPE AND DATES COVERED

Technical Report

4. TITLE AND SUBTITLE

Effect of Dynamic Envelope Pavement Markings on Vehicle Driver Behavior at a HighwayRail Grade Crossing

5. FUNDING NUMBERS

RR97A6/KT925

RR97A6/LT925 6. AUTHOR(S)

Scott H Gabree, Ph.D., Stephanie Chase Ph.D., and Marco daSilva

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

U.S. Department of Transportation

Research and Innovative Technology Administration

John A. Volpe National Transportation Systems Center

55 Broadway

Cambridge, MA 02142

8. PERFORMING ORGANIZATION 

REPORT NUMBER

DOT-VNTSC-FRA-13-05

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

U.S. Department of Transportation 

Federal Railroad Administration

Office of Railroad Policy and Development

Office of Research and Development

Washington, DC 20590

10. SPONSORING/MONITORING

AGENCY REPORT NUMBER

DOT/FRA/ORD-14/04

11. SUPPLEMENTARY NOTES

Program Manager: Tarek Omar, D.Sc.

12a. DISTRIBUTION/AVAILABILITY STATEMENT

This document is available to the public through the FRA Web site at http://www.fra.dot.gov.

12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200 words)

The U. S. Department of Transportation’s (U.S. DOT) Research and Innovative Technology Administration’s (RITA) John A. 

Volpe National Transportation Systems Center (Volpe Center), under the direction of the U.S. DOT Federal Railroad 

Administration (FRA) Office of Research and Development (R&D), conducted a research study to evaluate the effectiveness of 

roadway pavement markings placed within the dynamic envelope, the region between and immediately adjacent to the tracks at a 

highway-rail grade crossing, and new corresponding signage at the Commercial Boulevard grade crossing in Ft. Lauderdale, FL. 

The goal of the added markings and signage is to reduce the number of vehicles that come to a stop within the dynamic envelope,

a violation of most applicable State highway traffic laws, thus reducing the possibility that a vehicle is present on the tracks when 

a train approaches.

Results indicate that the addition of the dynamic envelope pavement markings and modified signage reduced the number of 

vehicles that stopped within the dynamic envelope zone and increased the number of vehicles that stopped properly—safely 

behind the stop line. Though these results seem to indicate that dynamic envelope pavement markings and signage may be an 

effective way to increase safe behavior, these safety enhancements have only been studied at one crossing. Additional field testing 

is necessary before recommendations for wider use can be made.

14. SUBJECT TERMS

highway-rail, grade crossing, driver behavior, violations, enhancement, safety, signage, pavement markings, dynamic envelope

15. NUMBER OF PAGES

49

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OF REPORT

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iv

METRIC/ENGLISH CONVERSION FACTORS

ENGLISH TO METRIC METRIC TO ENGLISH

LENGTH (APPROXIMATE) LENGTH (APPROXIMATE)

1 inch (in) = 2.5 centimeters (cm) 1 millimeter (mm) = 0.04 inch (in)

1 foot (ft) = 30 centimeters (cm) 1 centimeter (cm) = 0.4 inch (in)

1 yard (yd) = 0.9 meter (m) 1 meter (m) = 3.3 feet (ft)

1 mile (mi) = 1.6 kilometers (km) 1 meter (m) = 1.1 yards (yd)

1 kilometer (km) = 0.6 mile (mi)

AREA (APPROXIMATE) AREA (APPROXIMATE)

1 square inch (sq in, in2) = 6.5 square centimeters (cm2) 1 square centimeter (cm2) = 0.16 square inch (sq in, in2)

1 square foot (sq ft, ft2) = 0.09 square meter (m2) 1 square meter (m2) = 1.2 square yards (sq yd, yd2)

1 square yard (sq yd, yd2) = 0.8 square meter (m2) 1 square kilometer (km2) = 0.4 square mile (sq mi, mi2)

1 square mile (sq mi, mi2) = 2.6 square kilometers (km2) 10,000 square meters (m2) = 1 hectare (ha) = 2.5 acres

1 acre = 0.4 hectare (he) = 4,000 square meters (m2)

MASS - WEIGHT (APPROXIMATE) MASS - WEIGHT (APPROXIMATE)

1 ounce (oz) = 28 grams (gm) 1 gram (gm) = 0.036 ounce (oz)

1 pound (lb) = 0.45 kilogram (kg) 1 kilogram (kg) = 2.2 pounds (lb)

1 short ton = 2,000 pounds 

(lb)

= 0.9 tonne (t) 1 tonne (t) =

=

1,000 kilograms (kg)

1.1 short tons

VOLUME (APPROXIMATE) VOLUME (APPROXIMATE)

1 teaspoon (tsp) = 5 milliliters (ml) 1 milliliter (ml) = 0.03 fluid ounce (fl oz)

1 tablespoon (tbsp) = 15 milliliters (ml) 1 liter (l) = 2.1 pints (pt)

1 fluid ounce (fl oz) = 30 milliliters (ml) 1 liter (l) = 1.06 quarts (qt)

1 cup (c) = 0.24 liter (l) 1 liter (l) = 0.26 gallon (gal)

1 pint (pt) = 0.47 liter (l)

1 quart (qt) = 0.96 liter (l)

1 gallon (gal) = 3.8 liters (l)

1 cubic foot (cu ft, ft3) = 0.03 cubic meter (m3) 1 cubic meter (m3) = 36 cubic feet (cu ft, ft3)

1 cubic yard (cu yd, yd3) = 0.76 cubic meter (m3) 1 cubic meter (m3) = 1.3 cubic yards (cu yd, yd3)

TEMPERATURE (EXACT) TEMPERATURE (EXACT)

[(x-32)(5/9)] °F = y °C [(9/5) y + 32] °C = x °F

QUICK INCH - CENTIMETER LENGTH CONVERSION

0 1 2 3 4 5

Inches

Centimeters 0 1 2 3 4 5 6 7 8 9 10 11 12 13

QUICK FAHRENHEIT - CELSIUS TEMPERATURE CONVERSION

 -40° -22° -4° 14° 32° 50° 68° 86° 104° 122° 140° 158° 176° 194° 212°

 

°F

 °C -40° -30° -20° -10° 0° 10° 20° 30° 40° 50° 60° 70° 80° 90° 100°

For more exact and or other conversion factors, see NIST Miscellaneous Publication 286, Units of Weights and 

Measures. Price $2.50 SD Catalog No. C13 10286 Updated 6/17/98
v

Acknowledgements

The U.S. Department of Transportation (U.S. DOT) Federal Railroad Administration (FRA) 

Office of Research and Development sponsored the work leading to this report. The authors 

would like to thank Sam Alibrahim, Chief of the Train Control and Communications Division, 

FRA, and Tarek Omar, D.Sc., Program Manager, Train Control and Communications Division, 

FRA Office of Research and Development, for their guidance during the project and in 

developing this report.

The authors would like to thank Bianka Mejia, Surface Transportation Human Factors Division, 

U.S. DOT Research and Innovative Technology Administration’s John A. Volpe National 

Transportation Systems (Volpe Center), for her support in data collection and analysis. 

The authors would also like to thank William Baron, Security and Emergency Management 

Division, and Alan Kauffman of Computer Science Corporation, Volpe Center onsite contractor, 

for their technical support in data collection system development, installation, and maintenance.

Additional thanks to Brian Reeves, Florida Department of Transportation (FDOT) Office of 

Modal Development onsite contractor, as well as to the FDOT District Four field personnel for 

their part in supporting this evaluation effort. 
vi

Contents

Executive Summary........................................................................................................................ 1

1. Introduction ................................................................................................................. 2

1.1 Past Research............................................................................................................... 2

1.2 Background ................................................................................................................. 5

1.3 Overall Approach ........................................................................................................ 6

1.4 Organization of the Report.......................................................................................... 6

2. Pavement Markings and Signage ................................................................................ 7

3. Test Site Location and Data Collection..................................................................... 12

3.1 Test Site Location Characteristics............................................................................. 12

3.2 Data Collection.......................................................................................................... 16

4. Data Analysis Method ............................................................................................... 18

5. Results....................................................................................................................... 21

5.1 Traffic Patterns.......................................................................................................... 21

5.2 Motorist Stopping Behavior...................................................................................... 22

5.3 Violations .................................................................................................................. 30

5.4 Summary of Findings................................................................................................ 33

6. Conclusion and Discussion........................................................................................ 34

6.1 Next Steps.................................................................................................................. 34

7. Potential Limitations ................................................................................................. 36

8. References ................................................................................................................. 37

Appendix A. Additional Examples.............................................................................................. 38

Abbreviations and Acronyms ....................................................................................................... 41
vii

Illustrations

Figure 1. Barberville Rural Crossing with X-Box Markings (excerpted from Stevens and Long, 

2002) ....................................................................................................................................... 4

Figure 2. Example of Dynamic Envelope from MUTCD (Figure 8B-8) ....................................... 7

Figure 3. Schematic of Dynamic Envelope Zone Markings at Commercial Boulevard Grade 

Crossing .................................................................................................................................. 9

Figure 4. Accompanying Signage at Commercial Boulevard Grade Crossing ............................ 10

Figure 5. Dynamic Envelope Zone Pavement Markings at Commercial Boulevard.................... 11

Figure 6. Dynamic Envelope Zone Modified Signage at Commercial Boulevard ....................... 11

Figure 7. Commercial Boulevard Grade Crossing Satellite Image............................................... 12

Figure 8. Lane Coding Scheme for Commercial Boulevard Grade Crossing............................... 13

Figure 9. Example of Traffic Backed up on Westbound Lanes.................................................... 14

Figure 10. Example of Traffic Backed up on Eastbound Lanes................................................... 15

Figure 11. Camera Setup on Pole along Commercial Boulevard ................................................. 16

Figure 12. Camera and Solar Panel (left) and Utility Box (right) ................................................ 16

Figure 13. Camera Setup to Capture Eastbound (red) and Westbound (yellow) Traffic ............. 17

Figure 14. Zone Assignments....................................................................................................... 19

Figure 15. Proportion of Eastbound Vehicles Stopping by Zone ................................................. 23

Figure 16. Eastbound Zone 2 (yellow circles) and Zone 3 (red circle) Stopping Behaviors........ 23

Figure 17. Eastbound Zone 2 (yellow circle) and Zone 3 (red circles) Stopping Behaviors........ 24

Figure 18. Proportion of Westbound Vehicles Stopped by Zone ................................................. 25

Figure 19. Westbound Zone 1 (green circles) and Zone 4 (yellow circle) Stopping Behaviors... 26

Figure 20. Westbound Zone 1 (green circles), Zone 2 (yellow circle), Zone 3 (red circle), and 

Zone 4 (rightmost yellow circle) Stopping Behaviors.......................................................... 27

Figure 21. Example of a Vehicle Performing a U-Turn ............................................................... 29

Figure 22. Example of a Vehicle Changing Lanes to Exit Tracks................................................ 29

Figure 23. Eastbound Vehicles Trapped Inside Gates During an Activation ............................... 32

Figure 24. Westbound Vehicles Trapped Inside Gates During an Activation.............................. 32
viii

Tables

Table 1. Traffic Pattern by Lane: Pre- vs. Post-Installation ......................................................... 21

Table 2. Motorist Stopping Behavior by Zone ............................................................................. 22

Table 3. Vehicle Action in Zone 2, Zone 3, and Zone 4............................................................... 28

Table 4. Motorist Violations......................................................................................................... 30

Table 5. Pre-Installation Vehicles Stopped Beyond Gates During an Activation ........................ 31

Table 6. Post-Installation Vehicles Stopped Beyond Gates During an Activation....................... 31
1

Executive Summary

There are more than 212,000 highway-rail grade crossings in the United States. Deaths resulting 

from highway-rail grade crossing collisions and trespasser events account for approximately 95

percent of all rail-related fatalities each year. In 2013, there were 2,087 incidents at these 

highway-rail grade crossings. Of the 2,087 incidents, there were 943 injuries and 250 fatalities.1

In addition to the injuries and loss of life that occur at grade crossings, financial burdens from 

delays in service and damage to the train or track are also of concern. The Federal Railroad 

Administration (FRA) is involved with numerous wide-ranging engineering, education, and 

enforcement efforts to increase highway-rail grade crossing safety by reducing the number, 

frequency, and severity of incidents that occur each year. The study described in this document is 

a safety improvement effort being conducted by the Florida Department of Transportation 

(FDOT).

This study evaluated the effectiveness of pavement markings placed within the dynamic 

envelope, the region between and immediately adjacent to the tracks at a grade crossing, and new 

corresponding signage at the Commercial Boulevard grade crossing (ID# 628186E) in Ft. 

Lauderdale, FL. The goal of the added markings and signage is to positively influence driver 

behavior and reduce the number of vehicles that come to a stop within the dynamic envelope, 

thus reducing the possibility that a vehicle is present on the tracks when a train approaches,

which would not only be dangerous to the vehicle occupants but also to standers-by, train crews, 

and train passengers.

Researchers coded driver stopping behavior at this crossing for two 14-day periods. Vehicles 

were coded as having stopped in one of four zones: behind the stop line and gate arm (Zone 1), 

past the stop line but before the tracks (Zone 2), on the tracks (Zone 3), or immediately after the 

tracks (Zone 4). Stopping in Zone 3 is considered to be the most dangerous driver behavior, 

while stopping in Zone 1 is the safest.

Results indicate that the addition of the dynamic envelope pavement markings and modified 

signage reduced the proportion of vehicles that stopped in Zone 3. They also increased the 

proportion of vehicles that stopped in Zone 1. Additionally, fewer vehicles were found to stop in 

both Zone 2 and Zone 4, which are both moderately dangerous.

Despite the positive results with safe stopping behavior, there were less conclusive results when 

looking at motorists’ actions. Pavement markings and signage did not cause motorists to act 

differently once they had come to a stop in one of the dangerous zones, Zones 2–4 (i.e., drivers 

were not more likely to try to switch lanes or reverse to exit the crossing once stopped).

Though these results seem to indicate that dynamic envelope pavement markings and signage 

may be an effective way to increase safe stopping behavior, they have only been studied at one 

crossing. Additional field testing and analysis is necessary before more recommendations for 

wider use can be made.

 

1 Obtained from the FRA Office of Safety Analysis Web site: 

http://safetydata.fra.dot.gov/officeofsafety/default.aspx on April 4, 2014
2

1. Introduction

There are more than 212,000 highway-rail grade crossings in the United States. Deaths resulting

from highway-rail grade crossing collisions and trespasser events account for approximately 95 

percent of all rail-related fatalities each year. In 2013, there were 2,087 incidents at these 

highway-rail grade crossings. Of the 2,087 incidents, there were 943 injuries and 250 fatalities.

2

In addition to the injuries and loss of life that occur at grade crossings, financial burdens from 

delays in service and damage to the train or track are also of concern. FRA is involved with 

numerous wide-ranging engineering, education, and enforcement efforts to increase highway-rail 

grade crossing safety by reducing the number, frequency, and severity of incidents that occur 

each year. The study described in this document is a safety improvement effort being conducted 

by FDOT.

This study evaluated the effectiveness of pavement markings placed within the dynamic 

envelope and new corresponding signage at the Commercial Boulevard grade crossing (ID# 

628186E) in Ft. Lauderdale, FL. The goal of the added markings and signage is to reduce the 

number of vehicles that come to a stop within the dynamic envelope, thus reducing the 

possibility that a vehicle is present on the tracks when a train approaches.

1.1 Past Research

1.1.1 Pavement Markings and Signage

Though to our knowledge there have not been any studies of dynamic envelope pavement 

markings, studies on other types of pavement markings have been conducted since the 1960s. 

Early research studies on pavement markings, specifically edge line markings, were shown to 

reduce the likelihood of a crash (Musick, 1962; Basile, 1962). The safety benefit of edge line 

markings was shown in both studies to be most beneficial during nighttime driving, likely due to 

the reflectivity of the markings off the headlights. 

However, despite evidence that pavement markings (e.g., edge line markings) for roadway 

guidance purposes can provide added safety benefits, research on the safety benefits of pavement 

markings that are used for pedestrian or railroad crossings is less clear. For example, pedestrianmotor vehicle collisions were more than twice as likely to occur at sites marked with a crosswalk 

than at sites with no crosswalk markings; this was especially true at sites not accompanied by a 

traffic signal or stop sign, even after controlling for pedestrian and vehicle flow and crossing 

length (Koepsell, McCloskey, Wolf, Vernez-Moudon, Buchner, Kraus & Patterson, 2002). Other 

research has concluded that the addition of a sign prompting drivers to yield to pedestrians may 

help to improve safe driving behavior around pavement markings. Van Houten, Malenfant, and 

McCusker (2001) investigated driver behavior at pedestrian crosswalks after the installation of 

advance yield markings and an accompanying sign prompting motorists to yield to pedestrians at 

the markings. Findings showed that the pavement markings and corresponding signage increased 

the distance that motorists stopped in front of the crosswalk and decreased the number of motor 

 

2 Obtained from the FRA Office of Safety Analysis Web Site: 

http://safetydata.fra.dot.gov/officeofsafety/default.aspx on April 4, 2014
3

vehicle-pedestrian conflicts. This result was demonstrated with the signage placed at various 

distances from the pavement marking (10m, 15m, and 25m) all of which produced similar 

results. In 2004, Huybers, Van Houten, and Malenfant showed a similar change in driver 

behavior (i.e., reduction in vehicle-pedestrian conflicts and increased yielding distance) using 

advanced yield pavement markings and signage. However, they also determined that the same 

changes in driver behavior were found with only pavement markings, indicating that the 

pavement markings were the essential component producing safer driver behavior. 

Pavement markings and signage are also often used in an attempt to keep drivers from blocking 

intersections. The Manual of Uniform Traffic Control Devices (MUTCD) includes a section on 

“Do Not Block Intersection Markings.”3 The guidance in this section of the MUTCD includes 

pavement markings and signage. Pavement markings may include crosshatch lines or wording

such as “Do Not Block” or “Keep Clear.”. The signage described in the MUTCD says “Do Not 

Block Intersection” and is intended to be mounted before or above the intersection.

One such campaign aimed at reducing the number of vehicles stopping in major intersections 

was initiated in New York City in 1980. This effort, known as “Don’t Block the Box,” included 

the installation of crosshatch pavement markings covering several major intersections, along 

with accompanying signage which stated “Don’t Block the Box.” Ticket “blitzes” were also 

conducted to issue fines to individuals found to be blocking the intersection. However, a 2006 

report showed that the early positive impacts of this effort may have faded away (Stringer, 

2006)4. During a 9-hour period at 10 busy Manhattan intersections, 3,044 vehicles blocked the 

box and prevented traffic flow. Despite traffic officers being present for many of these incidents,

no tickets were issued. There is no known estimate of the number of vehicles blocking the box 

prior to this campaign, so the effect of this effort cannot be determined; however, a stronger 

enforcement presence may improve compliance.

1.1.2 Grade Crossing Pavement Markings and Signage

These previous studies show conflicting evidence regarding the safety benefits of pavement 

markings and accompanying signage. However, when such safety implementations are used at 

highway-rail grade crossings, different challenges must be considered. Specifically, at a 

highway-rail grade crossing it is important not only for vehicles to stop prior to the crossing 

when a train is present, but also for the safety instruments to alert drivers to a crossing ahead so 

that they do not come to a stop on the tracks at any point in time.

Driver stopping on the railroad tracks is an issue which has prompted the development of 

mitigation strategies to reduce this behavior. One such strategy is the preemption of traffic 

signals to turn green when gate activation occurs (Institute of Transportation Engineers, 1997). 

This preemption method is used across the United States and is intended to clear any possible 

queue of vehicles stopped on the tracks prior to the train’s arrival at the crossing. The MUTCD 

recommends that preemption be considered for any highway-rail grade crossing within 200 feet 

of a signalized intersection. The Institute of Transportation Engineers (ITE), a community of 

almost 17,000 transportation professionals, recommends preemption based on a detailed queuing 

 

3 http://mutcd.fhwa.dot.gov/htm/2009/part3/fig3b_18_longdesc.htm

4 http://www.mbpo.org/uploads/policy_reports/DONT%20BLOCK%20THE%20BOX.pdf
4

analysis. Such recommendations have prompted research into how best to manage traffic signal 

preemption at grade crossings based on characteristics of the crossing and traffic patterns (e.g., 

Long, 2003). 

Although preemption techniques can help to clear a crossing in the event that a train approaches 

the crossing, any situation in which a vehicle comes to a complete stop on the railroad tracks is 

dangerous. For example, a traffic signal near a grade crossing can create a situation where a line 

of vehicles builds up behind a red signal. If this line of vehicles backs up to the grade crossing, 

vehicles can choose to proceed forward onto the tracks behind the vehicle in front of them or 

wait a distance back. The best course of action that a driver can take is to wait to enter the 

crossing (i.e., stay behind the stop line where the gate arm is located) until the traffic has already 

cleared. This is the safest action that a motorist can take and never risks the driver being stuck on 

the tracks without a means to escape. However, motorists do not always behave safely and often 

enter the crossing before the traffic on the opposite site of the tracks has cleared, causing them to 

come to a stop on the tracks. One pavement marking design, the “X-box,” has been tested to 

measure its ability to keep drivers from entering the crossing until there is sufficient space on the 

opposite side of the track for their vehicle to exit the crossing. See Figure 1 for a representation 

of the “X-box” pavement marking, as shown in Stevens and Long, 2003.

Figure 1. Barberville Rural Crossing with X-Box Markings (excerpted from Stevens and 

Long, 2003)
5

The X-box is a 25-foot long rectangle with an “X” inside it that is drawn just beyond the tracks. 

This marking lets drivers know that if they cannot see the full “X,” there is not enough space for 

their vehicle to fit beyond the tracks and they should wait until the X-box has cleared before 

proceeding to cross the tracks. Stevens and Long (2003) studied two X-box installations to 

evaluate their effect on driver stopping behavior in an urban setting and in a rural setting, neither 

setting accompanied by signage. The urban environment tested in this study was on Commercial 

Boulevard in Ft. Lauderdale, FL, the same site being investigated in the current study. They 

found significant reductions in driver stopping behavior on or adjacent to the tracks in a rural 

setting, but found no significant change in driver stopping rates in an urban environment. 

Given that this X-box design was ineffective at increasing safe driver behaviors in an urban 

setting, it may be worthwhile to explore other options for alternative pavement markings or for 

added signage in an urban setting. The purpose of this study is to assess the effects of a new, 

more conspicuous pavement marking design and accompanying signage on driving behavior. 

This pavement marking design will not be placed after the crossing, but will completely fill the 

region known as the dynamic envelope between and around the railroad tracks.

1.2 Background

The Commercial Boulevard grade crossing in Ft. Lauderdale, FL, is a site where drivers often 

find themselves stopped on the railroad tracks. Since 1979, 20 incidents have been reported to 

FRA at this crossing and 18 of these incidents involved a vehicle coming to a complete stop on 

the tracks (the other two involved pedestrians)5

. The following vehicle-related incidents occurred 

at this crossing:

• The vehicle came to a stop on the tracks and could not or did not exit because of vehicles 

in front and a gate behind (n = 13).

• The vehicle was coded as having stopped before proceeding onto the tracks where it was 

then struck (n = 2).

• The vehicle went around the descended gates and was struck by the train (n = 1).

• The vehicle drove around the gates and into the train (n = 1). 

• The driver turned onto the tracks, mistaking the railway for a road (n = 1).

FDOT looked at driver behaviors at this crossing in a 2003 study of the South Florida Railroad 

Corridor. As a part of this effort, FDOT recorded video at several crossings along the South 

Florida Railroad Corridor, including the Commercial Boulevard grade crossing. During the 

study, 2,449 two-minute video clips were examined (for a total of more than 81 hours of video). 

According to these video clips, a total of 201 vehicles stopped on (149) or near (52) the tracks. 

The majority of those vehicles were stopping in inner lanes (i.e., not from the outermost lanes). 

Eastbound traffic at the Commercial Boulevard grade crossing was found to have the most 

problems of all the crossings studied. Seventy-two percent of the drivers who stopped on the 

tracks chose to take no action once stopped on the tracks (e.g., rather than reverse or change 

 

5 The 20 incidents can be found on the FRA Safety Data website. Incident numbers: 087907405, 088007405, 

078107404, 072981A, 108412407, 102284A, 1201874A, 128412403, 0904921, 1007931, 040494, 100112023, 

050312007, 112105, 000016942, 050906 (pedestrian), 010809 (pedestrian), 113075, 111909, 000081538
6

lanes). Lastly, drivers at this crossing also violated the crossing while the gates were in motion,

with westbound traffic violating more than twice as often as eastbound traffic.

FDOT decided to take action to increase safe driver behavior and reduce the number of incidents 

occurring at this crossing. FDOT determined that the best option for improving safe driving 

behaviors at this crossing was to add pavement markings to the area around the tracks known as 

the “dynamic envelope” and include accompanying signage instructing drivers not to stop in this 

area. The dynamic envelope is the area a train occupies as it passes through a crossing. Since a 

train extends beyond the track on which it travels, the dynamic envelope includes the track itself, 

the area between the rails, and 6 feet in either direction from the tracks (see section 2 for 

additional details). The goal of the pavement markings and signage is to make the zone on and 

around the tracks clearer to drivers. If the zone is more conspicuous, motorists may be more 

aware of the crossing and less likely to enter the tracks and be stuck as a train approaches.

1.3 Overall Approach

To understand the effect of the dynamic envelope pavement markings and signage on driving 

behavior, driver stopping behavior was coded both before and after the installation. Video data 

was collected 8 hours per day (from 7:30 to 9:30 a.m., 11 a.m. to 1 p.m., 4 p.m. to 6 p.m., and 10

p.m. to 12 a.m.) for 14 continuous days before installation and then again 4 weeks after 

installation. In total, 224 hours of video (112 before and 112 after dynamic envelope marking 

installation) were collected and analyzed to measure the effectiveness of this installation.

1.4 Organization of the Report

This report is organized as follows:

• Chapter 2 provides the dynamic envelope improvement specifications.

• Chapter 3 provides an overview of the test site location and data collection activities.

• Chapter 4 describes the analyses.

• Chapter 5 presents findings.

• Chapter 6 presents the conclusions of the study and offers recommendations for next 

steps.
7

2. Pavement Markings and Signage

The strategy that was chosen to reduce the number of motorists stopping on the railroad tracks 

was to paint the dynamic envelope with brightly colored paint and modify existing signage to 

match this new paint scheme. The MUTCD is a document developed by the Federal Highway 

Administration (FHWA) under 23 Code of Federal Regulations (CFR), Part 655, Subpart F,

which defines standards for the installation and maintenance of traffic control devices6. The most 

recent MUTCD (revised May 2012)7 defines the “Dynamic Envelope” as “the clearance required 

for light rail transit traffic or a train and its cargo overhang due to any combination of loading, 

lateral motion, or suspension failure.” Any object within the dynamic envelope has the potential 

to be struck by a train as the train passes through the crossing. Figure 2 shows an example of the 

dynamic envelope as defined in Figure 8B-8 of the MUTCD.

Figure 2. Example of Dynamic Envelope from MUTCD (Figure 8B-8)

 

6 http://mutcd.fhwa.dot.gov/

7 http://mutcd.fhwa.dot.gov/kno_2009r1r2.htm
8

For this implementation, the entire dynamic envelope was painted. The entire area between the 

two sets of tracks (and between each individual set of tracks) was painted yellow, while the area 

extending 6 feet outside the tracks was panted yellow with a white ‘X’ pattern. The schematic in 

Figure 3 shows where the yellow and white paint were applied to the crossing. 

In addition to the pavement markings, existing “DO NOT STOP ON TRACKS” (R8-8) signs 

were replaced with a modified R8-8 sign with a similar yellow and white pattern added to 

instruct motorists on how to behave at the crossing. The accompanying sign, which can be seen 

in Figure 4, displays the text ”DO NOT STOP ON TRACKS”. This modified signage replaced 

the existing signs on poles along the median of the boulevard and on the sidewalks on the 

opposite side of the tracks from the oncoming traffic. The signage facing eastbound traffic was 

placed at 65 feet (sidewalk sign) and 85 feet (median sign) past the stop line for the crossing. 

Both sidewalk and median signage facing westbound traffic were placed at 90 feet past the stop 

line for the crossing. Each newly modified sign was attached to the same poles to which the prior 

R8-8 sign had been secured. As with the original signage, this pole included flashing yellow 

lights to increase its conspicuity to approaching motorists. Images of the pavement marking (left 

and right) and signage (right) installation are shown in Figure 5 and Figure 6, respectively.

The installation occurred overnight over a 2-day period from December 9 to10, 2012. The 

installation of the pavement markings and associated signage at this crossing cost $37,000.
9

Figure 3. Schematic of Dynamic Envelope Zone Markings at Commercial Boulevard Grade Crossing8

 

8 Dynamic Envelope Plan obtained from FDOT District Four, April 2012
10

Figure 4. Accompanying Signage at Commercial Boulevard Grade Crossing9

 

9 Dynamic Envelope Plan obtained from FDOT District Four, April 2012
11

Figure 5. Dynamic Envelope Zone Pavement Markings at Commercial Boulevard

Figure 6. Dynamic Envelope Zone Modified Signage at Commercial Boulevard
12

3. Test Site Location and Data Collection

The site chosen for this effort was the grade crossing on Commercial Boulevard in Ft. 

Lauderdale, FL (ID# 628186E). This location was chosen by FDOT because of its historically 

high grade crossing crash risk.

3.1 Test Site Location Characteristics

There are two active railroad tracks which intersect with the Commercial Boulevard crossing.

According to the U.S. DOT Crossing Inventory data, approximately 51 trains move through this 

crossing daily at speeds ranging from 74 to 79 mph10. Both passenger (TriRail and Amtrak) and 

freight (CSX) trains pass through this crossing. The estimated daily highway user traffic at this 

crossing is 69,000 vehicles per day with a posted speed limit of 45 miles per hour (mph). Figure 

7 shows a satellite image of this area, with the specific crossing outlined by the white dashed 

box. 

Figure 7. Commercial Boulevard Grade Crossing Satellite Image

 

10 Grade crossing inventory data can be obtained from the FRA Safety Data website at 

http://safetydata.fra.dot.gov/OfficeofSafety/PublicSite/Crossing/Crossing.aspx. Data in this report was gathered on 

June 5, 2013.
13

3.1.1 Westbound

The location of the grade crossing is complex in many ways. First, the westbound traffic through 

the crossing is on a section of roadway immediately west of the off-ramp from Interstate 95.

There are four lanes for traffic traveling westbound through the crossing. Figure 8 shows the nine 

lanes that cross the tracks (four westbound and five eastbound) were coded numerically and are 

shown in Figure 8. 

Figure 8. Lane Coding Scheme for Commercial Boulevard Grade Crossing

Lane 1 includes primarily vehicles exiting from Interstate 95 South (I95S). There is a traffic light 

approximately 800 feet to the west of the grade crossing at Powerline Road; however, that road 

layout creates a situation in which traffic can back up into the crossing because of the long red 

light phase (the traffic light includes a 120-second red light and a 75-second green light phase). 

Figure 9 provides an example of traffic backing up through the crossing. Vehicles in both Lane 2 

and Lane 4 are backed up onto the tracks and a vehicle in Lane 4 has stopped before the tracks, 

but after the stop line.
14

Figure 9. Example of Traffic Backed up on Westbound Lanes
15

3.1.2 Eastbound

There are five lanes of traffic traveling eastbound through the crossing (see Figure 8 for 

representation of crossing). Lane 9 primarily includes vehicles entering the on-ramp for I95S. 

Vehicles typically use Lane 5 and Lane 6 to prepare to turn left after the traffic light to enter the 

on-ramp to I95N (this left turn is just after the I95 overpass that is to the east of the crossing in 

Figure 7). A traffic light approximately 150 feet from the grade crossing would likely create a 

traffic backup with a high volume of traffic pushed into the dynamic envelope for all lanes 

except Lane 9, which exits before the traffic light. Figure 10 shows an example of a traffic 

backup situation. No vehicles are stopped directly on the tracks in this example, but all lanes 

except Lane 9 are backed up and vehicles in Lane 5, Lane 6, and Lane 7 have all pulled past the 

stop line and risk being stuck inside the crossing if an activation occurs.

Figure 10. Example of Traffic Backed up on Eastbound Lanes
16

3.2 Data Collection

A video-based data collection system was installed at the crossing on May 23, 2012. Two 

separate systems were mounted on poles adjacent to the roadway to capture video of vehicles 

travelling in both directions on Commercial Boulevard. Each pole had a solar panel and camera 

mounted high on the pole to obtain a good vantage point from which to see vehicles passing 

through the crossing. Figure 11 shows an example of the pole with the solar panel and camera 

and utility box with battery and digital video recorder. Closer images of the camera and solar 

panel (left) and utility box (right) can be seen in Figure 12.

Figure 11. Camera Setup on Pole along Commercial Boulevard

 

Figure 12. Camera and Solar Panel (left) and Utility Box (right) 

Solar Panel and Camera

Utility Box
17

The utility box housed the following components: a solar controller, battery, fan, temperature 

and voltage loggers, temperature switch, and a digital video recorder (DVR).

Two of these setups (camera, solar panel, and utility box) were installed to monitor the 

Commercial Boulevard grade crossing traffic approaching from both sides. The locations of the 

two cameras can be seen in Figure 13. The red shading indicates the area captured by Camera 1, 

which was positioned to record westbound traffic, and the yellow shading indicates the area 

captured by Camera 2, which was positioned to record eastbound traffic.

Figure 13. Camera Setup to Capture Eastbound (red) and Westbound (yellow) Traffic

Camera 1

Camera 2
18

4. Data Analysis Method

The goal of this research study was to gain an understanding of how effectively the pavement 

markings on the dynamic envelope and accompanying signage at a highway grade crossing can 

influence driver behavior at grade crossings. The addition of the dynamic envelope markings and 

signage was intended to make this area more pronounced, resulting in fewer motorists entering 

the dynamic envelope if unable to exit the other side. 

To understand the effect of the dynamic envelope pavement markings and signage on driving 

behavior, driver stopping behavior was coded both before and after the installation. Video data 

was collected from the wayside cameras, 8 hours per day (between 7:30 and 9:30 a.m., 11 a.m. 

and 1 p.m., 4 and 6 p.m., and 10 p.m. and 12 a.m.) for 14 continuous days (a total of 112 hours of 

data before installation and then again 4 weeks after installation. The pre-installation data 

collection took place between May 26, 2012, and June 9, 2012 (no data was collected on 

Memorial Day, May 28). The pavement markings and signage modifications were installed on 

December 9 and 10, 2012, and the post-installation data collection took place between January 6 

and January 19, 2013. The 4 weeks between the installation of the markings and the postinstallation data collection allowed for drivers who frequently pass through this crossing to 

become familiar with the markings. The researchers ascertained that initial reactions to the new 

markings would likely not illicit behaviors that reflect long-term behavior changes. By delaying 

data collection for 4 weeks, the motorist behaviors as they approach the pavement markings were 

more likely to reflect longer term effects and not immediate novelty effects from the markings 

and signage. In total, 224 hours of video (112 before and after dynamic envelope marking 

installation) were collected and analyzed to measure the effectiveness of this installation.

A coder analyzed each of the 224 hours of video. If the coder was unsure how to code a specific 

vehicle, a second researcher was brought in to help make a determination. Researchers watched 

approximately 1 hour of videos alongside the coder initially to verify that the coding was being 

completed according to the established coding scheme. All data were entered into a Microsoft 

Excel spreadsheet for analysis.

Driver stopping behavior was coded based on four possible zones in which a motorist could 

come to a complete stop. The locations of these four zones are shown in Figure 14 below. A 

driver was considered to have stopped if:

• the driver’s forward momentum came to a complete halt, or

• the driver’s forward momentum slowed to a near stop because of stopped traffic directly 

ahead. 

Only vehicles that stopped in one of these four zones were coded (i.e., vehicles that passed 

through the crossing without stopping were not included in our study). In Zone 1, a vehicle was 

coded if the driver stopped in Zone 1 without any vehicles immediately in front of it. This coding 

scheme ensured that the driver stopping in Zone 1 was performing a safe behavior and not 

simply stopping because of traffic. Vehicles stopping in other zones had already chosen to 

perform an unsafe action, so a similar caveat was unnecessary. For example, if a driver came to a 

stop in Zone 3 with vehicles directly in front of him, he had already chosen to enter the grade 

crossing during an unsafe time (i.e., when traffic was backed up into the grade crossing). 

However, if a vehicle was stopped in Zone 1 because of traffic congestion, the driver may not 
19

have had an opportunity to decide to act safely or unsafely. Thus, we cannot determine how the 

driver would have acted without traffic forcing him or her to stop appropriately.

Figure 14. Zone Assignments

The four zones over the crossing represent different levels of danger if the motorist comes to a 

full stop in that zone:

• Zone 1 (not dangerous): A motorist who stops in Zone 1 has stopped before the stop line 

where the gate descends during an activation. Motorists stopping in this zone are 

behaving safely.

• Zone 2 (moderately dangerous): A motorist who stops in Zone 2 has stopped after the 

stop line, but before the dynamic envelope. Motorists stopping in Zone 2 would be stuck 

inside of a descended gate but not struck by a train.

• Zone 3 – Dynamic Envelope Zone (very dangerous): A motorist who stops in Zone 3 has 

stopped in the most dangerous part of the crossing—the dynamic envelope zone. In this 

zone, a train and vehicle would collide.

• Zone 4 (moderately dangerous): A motorist who stops in Zone 4 has stopped past but 

adjacent to the dynamic envelope zone. Motorists stopping in Zone 4 would not be struck 

by a train.
20

Motorists are always coded by the most dangerous zone in which they stop so that each motorist 

is counted only once. For example, if a motorist initially approached the crossing and stopped 

behind the stop line in Zone 1, but then proceeded to enter the crossing and stop in Zone 3, that 

motorist would be coded as stopping in Zone 3. In addition to the zone in which a motorist 

stopped, the action taken to exit the zone was also coded. This way, the initial behavior of the 

motorist (i.e., where the motorist chose to stop, as well as his or her subsequent action—

changing lanes, waiting for traffic to clear, reversing out of the dynamic envelope zone) could be 

tracked. Both of these actions provide information about the motorist’s decision-making process 

as he or she approaches and enters the crossing.

If the pavement markings in the dynamic envelope and accompanying modified signage are able 

to impact driver safety, a change in drivers’ overall stopping zone would be observed. 

Specifically, we may expect the following changes in driving behavior:

• A decrease in motorists stopping in Zone 3 after the installation of the pavement 

markings and signage. 

• An increase in motorists stopping in Zone 1 after the installation of the pavement 

markings and signage.

• A slight increase in motorists stopping in Zone 2 and Zone 4 after the installation of the 

pavement markings and signage. This prediction is less certain since it is unclear how the 

dynamic envelope markings will impact the moderately dangerous zones adjacent to it. 

However, one may expect a slight increase in the number of motorists stopping in Zone 2 

and Zone 4 because the signage which accompanies the pavement markings instructs 

drivers to “not stop on tracks” and not to stay behind the stop line. Therefore, drivers may 

not stop on the tracks, but may continue to stop after the stop line, but before the tracks.
21

5. Results

From the 224 hours of data collection, a total of 12,989 vehicles were coded. Prior to the 

installation of the dynamic envelope pavement markings, 6,230 vehicles were coded; after the 

installation of the pavement markings, 6,759 vehicles were coded.

5.1 Traffic Patterns

Traffic patterns by lane before and after the installation of the dynamic envelope pavement 

markings were similar. The traffic patterns by lane can be seen in Table 1 (Note: percentages are 

relative to one direction of traffic and not both). 

Table 1. Traffic Pattern by Lane: Before vs. After Installation

Lane Pre-Installation Post-Installation

Westbound

1 1,118 (35.1%) 1,348 (39.1%)

2 548 (17.2%) 583 (16.9%)

3 767 (24.1%) 781 (22.6%)

4 754 (23.7%) 739 (21.4%)

1 – 4 

Total 3,187 (100%) 3,440 (100%)

Eastbound

5 900 (29.6%) 803 (24.3%)

6 754 (24.8%) 840 (25.4%)

7 767 (25.2%) 958 (29.0%)

8 324 (10.6%) 435 (13.2%)

9 298 (9.8%) 272 (8.2%)

5 – 9 

Total 3,043(100%) 3,319 (100%)

Both

Overall

TOTAL 6,230 6,759

Patterns for westbound traffic were similar, with the largest amount of traffic passing through the 

crossing in Lane 1 (the off-ramp from I95) and the least traffic passing through the crossing in 

Lane 2. However, a chi-square analysis reveals that the patters of traffic did differ before and 

after installation (χ2 = 29.92, df = 3, p<0.01). This difference owes primarily to the increase in 

Lane 1 traffic (and small decreases in each of the other lanes). Eastbound traffic showed slightly 

different patterns before and after the installation of the pavement markings and signage. A chisquare test revealed a significant change in the lanes used to travel through the crossing (χ2

= 
22

78.48, df = 3, p<0.01). This change was primarily driven by a large decrease in Lane 5 traffic 

and increases in traffic in Lane 7 and Lane 8.

Despite significant changes in traffic pattern by lane, the overall amount of traffic was relatively 

similar. Lane-specific effects are not being studied as a part of this initial effort, but will be 

included in future, more in-depth analyses. For the purposes of this study, it is assumed that 

motorists will see the newly installed pavement markings from any of the nine lanes and react 

similarly regardless of the lane in which they choose to drive.

5.2 Motorist Stopping Behavior

The main indicator for this study was where motorists came to a stop as they approached the 

tracks. Table 2 reports this stopping behavior, along with the number and percentage of vehicles 

that stopped in each of the four zones. Stopping behavior is shown separately for eastbound and 

westbound traffic.

Table 2. Motorist Stopping Behavior by Zone

Eastbound Traffic Westbound Traffic

Zone Stopped Pre-Install Post-Install Pre-Install Post-Install

Zone 1 1,890 (62.1%) 2,244 (67.6%) 1,926 (60.4%) 2,209 (64.2%)

Zone 2 832 (27.3%) 875 (26.4%) 749 (23.5%) 784 (22.8%)

Zone 3 216 (7.1%) 130 (3.9%) 400 (12.6%) 369 (10.7%)

Zone 4 105 (3.5%) 70 (2.1%) 112 (3.5%) 78 (2.3%)

Total 3,043 3,319 3,187 3,440

For eastbound traffic, the installation of the pavement markings elicited a significant change in 

behavior. A chi-square test of independence showed a significant difference between the pre- and 

post-installation conditions (χ2=82.22, df = 3, p <0.01). This change in driver behavior is 

evidenced by a 45 percent reduction in motorists stopping in Zone 3, a 39 percent reduction in 

motorists stopping in Zone 4, and a 9 percent increase in motorists stopping appropriately in 

Zone 1. These changes in proportion can be seen graphically in Figure 15.
23

Figure 15. Proportion of Eastbound Vehicles Stopping by Zone (Pre-Install n = 3,043 and 

Post-Install n = 3,319)

Examples of eastbound vehicles stopped in each of the zones are provided in Figure 16 and 

Figure 17. In Figure 16, two vehicles (circled in yellow) have come to a stop after the stop line 

but before the crossing in Zone 2, and one vehicle (circled in red) has come to a stop with its rear 

bumper still in Zone 3. All other vehicles are moving through the crossing.

Figure 16. Eastbound Zone 2 (yellow circles) and Zone 3 (red circle) Stopping Behaviors
24

In Figure 17, the two vehicles circled in red are both at least partially in Zone 3, while the 

vehicle circled in yellow has come to a stop in Zone 2. 

Figure 17. Eastbound Zone 2 (yellow circle) and Zone 3 (red circles) Stopping Behaviors
25

Similar patterns were found for westbound traffic. Significant changes in driver stopping 

behavior were found from before to after the installation of the pavement markings and signage 

(χ2

=31.72, df = 3, p <0.01). The decrease in vehicles stopping in Zone 3 was 14 percent—less 

substantial than for eastbound traffic. Further, the coders noted a 6 percent increase in Zone 1

stopping and a 36 percent decrease in Zone 4 stopping. These changes in proportion can be seen 

graphically in Figure 18.

Figure 18. Proportion of Westbound Vehicles Stopped by Zone (Pre-Install n = 3,187 and 

Post-Install n = 3,440)
26

Examples of vehicles stopping in each of the zones are provided in Figure 19 and Figure 20. In 

Figure 19, the two vehicles circled in green have come to a full stop in Zone 1, behind the stop 

line. The vehicle circled in yellow has fully exited the crossing; however, it is very close to the 

tracks and is considered to be in Zone 4. The two vehicles seen on the tracks were moving and 

never came to a stop in the crossing; thus, they were not coded.

Figure 19. Westbound Zone 1 (green circles) and Zone 4 (yellow circle) Stopping Behaviors
27

In Figure 20, vehicles stopping in all four zones can be seen. The vehicles circled in green have 

come to a full stop in Zone 1, behind the stop line. The vehicle circled in red has come to a full 

stop in Zone 3, on the tracks. The two vehicles circled in yellow stopped in Zone 2 (the 

uppermost yellow circle) and in Zone 4 (the lower and rightmost yellow circle).

Figure 20. Westbound Zone 1 (green circles), Zone 2 (yellow circle), Zone 3 (red circle), 

and Zone 4 (rightmost yellow circle) Stopping Behaviors
28

A vehicle which stops in a zone has four possible choices for action: changing lanes, reversing, 

performing a U-turn, or taking no action and waiting for traffic in front to clear. For this analysis, 

only vehicles that stopped in Zone 2, Zone 3, or Zone 4 are considered. We chose to exclude 

Zone 1 from this analysis because a driver choosing to take no action in Zone 1 is acting safely 

(that driver has yet to enter the crossing, so waiting is appropriate), whereas choosing to take no 

action in Zones 2, 3, or 4 is potentially dangerous. Findings showed that the majority of drivers 

for both eastbound and westbound traffic chose to take no action after stopping in Zone 2, Zone 

3, or Zone 4. See Table 3 for details about vehicle actions in Zones 2, 3, and 4.

Table 3. Vehicle Action in Zone 2, Zone 3, and Zone 4

Eastbound Traffic Westbound Traffic

Motorist Action Pre-Install Post-Install Pre-Install Post-Install

Change Lane 34 (2.9%) 27 (2.5%) 78 (6.2%) 79 (6.4%)

Reverse 9 (0.8%) 6 (0.5%) 5 (0.4%) 7 (0.6%)

U-Turn 25 (2.2%) 30 (2.8%) 7 (0.6%) 7 (0.6%)

No Action 1,085 (94.1%) 1,011 (94.1%) 1,171 (92.9%) 1,138 (92.4%)

Total 1,153 1,074 1,261 1,231

Neither eastbound nor westbound traffic showed a significant change in vehicle action following 

the installation of the pavement markings and signage (Eastbound: χ

2

=3.30, df = 3, p >0.05 and 

Westbound: χ2=1.05, df = 3, p >0.05). This indicates that though drivers may have changed their 

decisionmaking process prior to entering the crossing, once they found themselves in the 

crossing and at a stop, there was little change in their behaviors. Examples of these behaviors can 

be seen in Figure 21 (U-turn) and Figure 22 (lane change).
29

Figure 21. Example of a Vehicle Performing a U-Turn

Figure 22. Example of a Vehicle Changing Lanes to Exit Tracks
30

5.3 Violations

Although the dynamic envelope pavement markings are intended to deter drivers from stopping 

in the dynamic envelope, they may also affect a driver’s willingness to violate a crossing during 

an activation event. To assess this possibility, researchers analyzed vehicles that violated the 

crossing during a train activation. Two types of violations were considered, each with varying 

levels of potential danger:

• Descending Violation (moderately dangerous): A descending violation is one in which a 

motorist passes underneath the gates after they have initiated their descent but are not yet 

horizontal. 

• Horizontal Violation (most dangerous): A horizontal violation is one in which a motorist 

drives around or through the fully descended gate.

All violations that were observed during the study timeframe are reported in Table 4. Note that 

there are no horizontal violations in this table. At this crossing, when the gates are horizontal 

they cover the entire roadway. When combined with the median between the east and westbound 

traffic, a driver would be required to break the gate in order to violate while the gate arm was 

horizontal.

Table 4. Motorist Violations

Descending Violations

Lane

Pre-Install

(291 Activations)

Post-Install

(287 Activations)

Westbound

1 104 49

2 88 26

3 66 23

4 71 19

Eastbound

5 34 23

6 47 34

7 42 29

8 35 17

9 99 60

TOTAL 586 280

The number of descending violations decreased by more than 50 percent following the 

installation of the pavement markings and modified signage (note: after installation there were 

four fewer train activations). This indicates that the pavement markings and signage may have 

been effective at reducing drivers’ likelihood to enter the crossing after the gates had initiated 

descent.
31

Although potentially dangerous (i.e., during a second train event), ascending violations, which 

occur when motorists pass underneath the gate as it ascends following an activation, were not 

tracked in this analysis because of the large number of vehicles committing this violation. 

Almost all vehicles positioned to cross the stop line did so as soon as they were able to fully pass 

under the ascending gate. Anecdotally, it seemed as if the presence of the dynamic envelope 

markings and signage had no impact on ascending violations.

No train-vehicle collisions occurred during this study, although on nine occasions a vehicle was 

stuck between the fully descended gates and the tracks during an activation event. Four of these 

incidents occurred prior to the installation of the pavement markings and signage, whereas five 

incidents occurred after. Additional details about the vehicles location can be found in Table 5

(pre-installation) and Table 6 (post-installation).

Table 5. Pre-Installation Vehicles Stopped Beyond Gates during an Activation

Pre-Installation of Pavement Markings and Signage

Vehicle # Date Traffic 

Direction Lane

Adjacent 

Lane 

Open?

Train 

Direction

1 5/29/2012 Eastbound 5 Yes Northbound

2 6/5/2012 Eastbound 6 Yes Southbound

3 6/5/2012 Eastbound 5 Yes Northbound

411 6/5/2012 Eastbound 6 Yes Northbound

Table 6. Post-Installation Vehicles Stopped Beyond Gates during an Activation

Post-Installation of Pavement Markings and Signage

Vehicle # Date Traffic 

Direction Lane

Adjacent 

Lane 

Open?

Train 

Direction

5 1/8/2013 Westbound 4 Yes Southbound

6 1/8/2013 Westbound 4 Yes Northbound

712 1/8/2013 Westbound 3 Yes Northbound

8 1/10/2013 Eastbound 5 Yes Southbound

9 1/18/2013 Eastbound 5 Yes Northbound

 

11 Vehicle 4 was trapped beyond the gates during the same activation as Vehicle 3. They were in adjacent lanes, as 

seen in Figure 23.

12 Vehicle 7 was trapped beyond the gates during the same activation as Vehicle 6. They were in adjacent lanes, as 

seen in Figure 24.
32

These findings are somewhat surprising. The jump from zero westbound incidents in the preinstallation timeframe to three incidents for westbound traffic in the post-installation timeframe 

is especially surprising. Also unexpected is the fact that at least one adjacent lane was open in 

each of these incidents, indicating that vehicles could have acted to exit the crossing but chose to 

remain trapped. An example of a vehicle trapped inside the gates is provided in Figure 23

(eastbound) and Figure 24 (westbound). Appendix A provides additional examples of this type of 

incident.

Figure 23. Eastbound Vehicles Trapped Inside Gates during an Activation

Figure 24. Westbound Vehicles Trapped Inside Gates during an Activation
33

5.4 Summary of Findings

Overall, the addition of the dynamic envelope pavement markings and signage had a positive 

effect on driver stopping behaviors at grade crossings. 

To specifically address the study’s predictions:

• A decrease will be seen in motorists stopping in Zone 3 after the installation of the 

pavement markings and signage. 

Findings: We observed a 45 percent reduction in the number of motorists stopped in 

Zone 3 eastbound and a 15 percent reduction for westbound vehicles after installation.

• An increase in motorists stopping in Zone 1 after the installation of the pavement 

markings and signage.

Findings: We observed a 9 percent increase in the number of motorists stopped in Zone 1 

eastbound and a 6 percent increase for westbound vehicles after installation

• A slight increase in motorists stopping in Zone 2 and Zone 4 after the installation of 

the pavement markings and signage.

Findings: We observed a slight decrease in motorists stopped in Zone 2 both eastbound

and westbound, but a 39 percent decrease in the number of motorists stopping in Zone 4 

eastbound and a 36 percent decrease for westbound vehicles after installation.

• A reduction in the number of violations post installation (both horizontal and 

descending).

Findings: Descending violations were reduced by more than 50 percent after the 

installation of the pavement markings and modified signage. No horizontal violations 

took place before or after installation. Nine incidents occurred where a vehicle was stuck 

inside the gates during an activation; four motorists heading eastbound were stuck 

between the fully descended gate and the tracks before installation; and five motorists 

(two eastbound and three westbound) were stuck after installation. 

Additional findings:

There was no significant change found in the specific actions taken by motorists in Zones 2 to 4 

before and after installation, indicating that once they found themselves stopped in the crossing,

they initiated the same type of actions (e.g., waiting for traffic to clear, a U-turn, or lane change).

The lanes that motorists used were significantly different before and after installation, with 

eastbound traffic showing a significant decrease in Lane 5 usage and an increase in both Lane 7 

and Lane 8, and westbound traffic increasing in Lane 1 (off ramp from I95) after installation.

It is also important to note that the traffic patterns changed from before and after installation,

which affected the amount of data collected with 6,230 vehicles before installation and 6,759 

after installation. Based on our findings thus far, there is no evidence to suggest that this 

difference would skew our findings.
34

6. Conclusion and Discussion

Pavement markings in the dynamic envelope and the accompanying signage were effective at 

changing driver behavior around the Commercial Boulevard grade crossing. Fewer drivers 

entered the crossing and came to a stop on the tracks after the dynamic envelope had been 

painted and signage was installed (percent decreases of 45 percent for eastbound traffic and 14

percent for westbound traffic). This reduction in unsafe stopping behavior was coupled by an 

increase in safe driving behavior where the driver came to a full stop before the stop line before 

the crossing (percent increases of 9 percent for eastbound traffic and 6 percent for westbound 

traffic). 

Drivers were also less likely to stop in the moderately unsafe regions immediately before or after 

the dynamic envelope. This may indicate that the pavement markings and modified signage were 

effective at making drivers aware of the crossing as a whole and not just the dynamic envelope. 

One might have anticipated that the increased visibility of the signage, which stated “Do Not 

Stop on Tracks,” and the painting of the dynamic envelope may have resulted in an increase of 

drivers choosing to stop in the region beyond the stop line, but before the newly painted dynamic 

envelope. However, it seems that the markings and signage instead resulted in an increase in the 

safest behavior, stopping before the stop line, while all other stopping behaviors decreased.

Despite the positive effects on driver stopping behavior, the pavement markings and signage 

seemed to have little effect once the motorist had already stopped. Once a driver chose to stop in 

Zone 2, Zone 3, or Zone 4, the driver typically chose not to actively attempt to remove the 

vehicle from this zone. Instead drivers tended to wait until traffic cleared to proceed through the 

crossing. The addition of the pavement marking and modified signage had no effect on this 

behavior.

Lastly, the pavement markings and signage did not result in a reduction in the number of 

vehicles getting stuck on the inside of the gates during an activation. In fact, during the 

timeframe prior to the installation of the improvements, no such event was recorded for 

westbound traffic; however, after installation there were three such events.

The results of this study provide initial evidence that dynamic envelope pavement markings with 

signage can cause an increase in safe stopping behaviors. However, to better understand the 

impact these makings and signage may have at another grade crossing, further exploration is 

required.

6.1 Next Steps

Though this study provided a great deal of information about the impact of dynamic envelope 

pavement markings and signage, additional exploration may reveal more information. There are 

several aspects of the current data collection that require added attention; for example, how the 

data collected at this site will compare with data collected from other sites. 

The following are potential next steps for this study:

• A detailed analysis of the effects of time-of-day on stopping behavior. The current report 

does not include a detailed account of the effect of traffic density or daylight on stopping 

behavior. Both of these variables may play a role in influencing driver behavior.
35

• A lane-by-lane analysis to see if the inner lanes were affected by the pavement markings 

and signage differently than the outer lanes. For example, the signage may have been 

more visible to the outer lanes, resulting in an increase in safe driving behavior. 

Alternatively, the outer lanes may also have had more vehicles planning to turn and thus 

drivers may have been focused on the road up ahead and missed the markings or signage.

• A more complete understanding of the effects of time of year on driver behavior. Though 

not a part of this effort, it is possible that seasonal variations may arise. This may be due 

to lighting, type of driver (more local versus visiting drivers), or weather. This 

information may help to better determine the locations best suited for a potential followup installation.

• A comparison with another highway-rail grade crossing to better understand how much 

the geometry of the Commercial Boulevard grade crossing impacted results. For 

example, among other attributes, the Commercial Boulevard grade crossing has tracks 

which are not perpendicular to the roadway, a highway off-ramp leading directly into the 

crossing, and a highway on-ramp immediately after the crossing. Each of these

characteristics may affect the way vehicles react to the markings and signage. Testing 

similar implementations at other grade crossings may help to better understand if a 

certain crossing geometry (e.g., parallel tracks) is better suited to this type of 

implementation.
36

7. Potential Limitations

This study was carefully designed to evaluate the effects of the Commercial Boulevard 

implementation of dynamic envelope pavement markings and modified signage; therefore, there 

are particular aspects of the crossing which may make the results difficult to translate to some 

other grade crossing situations. First, though the amount of time over which videos were 

recorded was consistent between pre- and post-installation conditions, the overall number of 

vehicles that stopped varied (529 more vehicles stopped in the post-installation condition). The 

numbers reported in this document represent the proportion of vehicles stopping in each zone; 

however, it is possible that the increased traffic in the post-installation condition may have 

elicited different driver behaviors.

The specifics of the site tested in this study also pose some potential limitations. As described 

earlier in this document, the grade crossing chosen for this study was unique in many ways. It 

was directly adjacent to both the on-ramp and off-ramp of a major freeway. Motorists entering or 

exiting the freeway may have had a different mindset as they entered the crossing compared with 

motorists who approached the crossing straight on and continued straight past the crossing. 

Another limiting factor may have been the placement of the accompanying signage. This signage 

was the only information drivers received regarding the action expected of them when they saw 

the dynamic envelope markings. However, this signage was placed on the opposite side of the 

tracks from the approaching traffic, so drivers may have been unable to clearly see and

understand the modifications on the signage prior to arriving at the crossing, and at that point, it 

may have been too late to alter their decision to enter the dynamic envelope. Additionally, 

because of the geometry of the track-road intersection at that location, motorists traveling 

westbound arrived at the tracks sooner after the stop line (and further from the signage) than 

motorists traveling eastbound. This non-perpendicular geometry may partially explain why the 

impact of the dynamic envelope pavement markings and signage was different for eastbound and 

westbound traffic. It is worth noting that similar signage (i.e., the same sign without the added 

yellow markings at the top and bottom) was in place prior to the installation of the pavement 

markings. However, the modification of the signage directly linked the sign to the dynamic 

envelope with the yellow crosshatch pattern and provided drivers with the only direct 

instructions for how to act around the new pavement markings.

Lastly, the pre- and post-installation data collections were completed during different times of 

the year. The pre-installation collection was completed in late May and early June, whereas the 

post-installation collection was completed in January. Although at this particular location there is 

no concern about inclement winter weather, there may be different types of drivers during the 

different times of year. For example, drivers in the winter may be more likely to be local drivers 

(rather than visitors) compared with drivers in the spring and/or summer. These different driving 

populations may result in different baseline behaviors for the two groups regardless of any 

markings or signage.
37

8. References

Basile, A.J. Effect of Pavement Edge Markings on Traffic Accidents in Kansas. In Highway 

Research Board Bulletin 308, Highway Research Board, National Research Council, 

Washington, DC, 1962, pp. 80-86.

Courage, K. & Kirkpatrick, B. (2003). Video Based Studies of Flexible Traffic Separators at 

Highway-Railroad Grade Crossings. Florida Department of Transportation.

Koepsell, T., McCloskey, L., Wolf, M., Moudon, A. V., Buchner, D., Kraus, J., & Patterson, M. 

(2002). Crosswalk markings and the risk of pedestrian–motor vehicle collisions in older 

pedestrians. JAMA: the journal of the American Medical Association, 288(17), 2136-2143.

Lenne, M. G., Rudin-Brown, C. M., Navarro, J., Edquist, J., Trotter, M., & Tomasevic, N. 

(2011). Driver behaviour at rail level crossings: Responses to flashing lights, traffic signals 

and stop signs in simulated rural driving. Applied ergonomics, 42(4), 548-554.

Long, G. (2003). Easy-to-apply solution to a persistent safety problem: clearance time for 

railroad-preempted traffic signals. Transportation Research Record: Journal of the 

Transportation Research Board, 1856(1), 239-247.

Manual on Uniform Traffic Control Devices for Streets and Highways, U.S. Department of 

Transportation, Federal Highway Administration, Washington D.C., 1988.

Musick, J. V. Effect of Pavement Edge Marking on Two-Lane Rural State Highways in 

Ohio. Highway Research Board Bulletin 266, 1962, pp. 1-7.

Preemption of Traffic Signals at or near Railroad Grade Crossings with Active Warning Devices: 

A Recommended Practice. Traffic Engineering Council Committee TENC- 4M-35, Institute 

of Transportation Engineers, Washington, DC, February 1997.

Stephens, B. W., & Long, G. (2003). Supplemental pavement markings for improving safety at 

railroad-highway grade crossings. Transportation Research Record: Journal of the 

Transportation Research Board, 1844(1), 18-24.

The 1981 Highway Safety Stewardship Report. Report of the Secretary of Transportation to the 

United States Congress, Office of Highway Safety, Federal Highway Administration, U.S. 

Department of Transportation, Washington, DC, April 1981.

Traffic Engineering Council Committee 4M-35, Recommended Practice, Preemption of Traffic 

Signals At or Near Railroad Grade Crossings with Active Warning Devices, Institute of 

Transportation Engineers, Washington DC, 1997.

Ward, N. J., & Wilde, G. J. (1995). Field observation of advance warning/advisory signage for 

passive railway crossings with restricted lateral sightline visibility: An experimental 

investigation. Accident Analysis & Prevention, 27(2), 185-197.

Zegeer, C. V., Stewart, J. R., Huang, H., & Lagerwey, P. (2001). Safety effects of marked versus 

unmarked crosswalks at uncontrolled locations: analysis of pedestrian crashes in 30 

cities. Transportation Research Record: Journal of the Transportation Research 

Board, 1773(1), 56-68.
38

Appendix A. 

Additional Examples

Below are additional examples of vehicles that stopped on or near the tracks during the study 

timeframe. Vehicles circled in green were coded as having stopped in Zone 1. Vehicles circled in 

red were coded as having stopped in Zone 3. Vehicles circled in yellow were coded as being in 

Zone 2 if they were yet to cross the tracks and Zone 4 if they were already past the tracks. Not all 

vehicles were circled (only those that stopped in one of the four zones and were coded as such).

• Westbound

Figure A- 1. Westbound Vehicles Stopped in Zone 1 and Zone 4
39

Figure A- 2. Westbound Truck Stopped in Zone 3

Figure A- 3. Many Westbound Vehicles Stopped on or Near the Tracks
40

• Eastbound

Figure A- 4. Eastbound Vehicles Stopped in Zone 2 and Zone 4

Figure A- 5. Eastbound Vehicles Stopped in Zone 2 and Zone 3
41

Abbreviations and Acronyms

FDOT

FHWA

Florida Department of Transportation

Federal Highway Administration

FRA Federal Railroad Administration

ITE Institute of Transportation Engineers

mph miles per hour

MUTCD Manual on Uniform Traffic Control Devices

ROW Right-Of-Way

U.S. DOT U.S. Department of Transportation

Volpe Center John A. Volpe National Transportation Systems