U.S. Department of 

Transportation

Federal Railroad 

Administration

Low-Cost Warning Device Industry Assessment

Office of Research

and Development

Washington, DC 20590

DOT/FRA/ORD-10/06 Final Report

July 2010

Safety of Highway Railroad Grade Crossings

DOT/FRA/ORD-0X/XX
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4. TITLE AND SUBTITLE

Low-Cost Warning Device Industry Assessment

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6. AUTHOR(S) RR97A1/FG276

Adrian D. Hellman and Tashi Ngamdung

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

Cambridge, MA 02142

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DOT-VNTSC-FRA-09-12

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U.S. Department of Transportation

Federal Railroad Administration

Office of Research and Development

1200 New Jersey Avenue, SE

Washington, DC 20590

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AGENCY REPORT NUMBER

DOT/FRA/ORD-10/06

11. SUPPLEMENTARY NOTES

Safety of Highway-Railroad Grade Crossings series

Program Manager: Leonard Allen

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

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13. ABSTRACT (Maximum 200 words)

Under direction of the Federal Railroad Administration’s Office of Research and Development, the U.S. Department of 

Transportation’s Research and Innovative Technology Administration’s John A. Volpe National Transportation Systems Center 

conducted a technology assessment of low-cost active warning devices for application at passive highway-rail grade crossings. 

The objective of this research was to present an objective assessment of the available low-cost warning device technologies and 

recommend a migration path that would facilitate implementation in the United States. 

14. SUBJECT TERMS

Highway-rail, grade crossing, low-cost warning devices, railroad safety

15. NUMBER OF PAGES

47

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NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89) 

Prescribed by ANSI Std. 239-18

298-102
ii

METRIC/ENGLISH CONVERSION FACTORS

ENGLISH TO METRIC METRIC TO ENGLISH

LENGTH 

1 inch (in)

1 foot (ft)

1 yard (yd)

1 mile (mi)

(APPROXIMATE)

= 2.5 centimeters (cm)

= 30 centimeters (cm)

= 0.9 meter (m)

= 1.6 kilometers (km)

 

AREA (APPROXIMATE)

1 square inch (sq in, in2

) = 6.5 square centimeters 

(cm2

) 

1 square foot (sq ft, ft2

) = 0.09 square meter (m2) 

1 square yard (sq yd, yd2) = 0.8 square meter (m2) 

1 square mile (sq mi, mi2

) = 2.6 square kilometers 

(km2

) 

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

) 

MASS - WEIGHT (APPROXIMATE)

1 ounce (oz) = 28 grams (gm)

1 pound (lb) = 0.45 kilogram (kg)

1 short ton = 2,000 = 0.9 tonne (t)

pounds (lb)

1 

VOLUME

1 teaspoon (tsp)

1 tablespoon (tbsp)

1 fluid ounce (fl oz)

1 cup (c)

1 pint (pt)

1 quart (qt)

1 gallon (gal)

1 cubic foot (cu ft, ft3

) 

cubic yard (cu yd, yd3

) 

(APPROXIMATE)

= 5 milliliters (ml)

= 15 milliliters (ml)

= 30 milliliters (ml)

= 0.24 liter (l)

= 0.47 liter (l)

= 0.96 liter (l)

= 3.8 liters (l)

= 0.03 cubic meter 

= 0.76 cubic meter 

(m3) 

(m3

) 

TEMPERATURE

[(x-32)(5/9)] °F = y °C 

(EXACT)

LENGTH (APPROXIMATE)

1 millimeter (mm) = 0.04 inch (in)

1 centimeter (cm) = 0.4 inch (in)

1 meter (m) = 3.3 feet (ft)

1 meter (m) = 1.1 yards (yd)

1 kilometer (km) = 0.6 mile (mi)

AREA (APPROXIMATE)

 square centimeter (cm2

) = 0.16 square inch (sq in, in2) 

1 square meter (m2

) = 1.2 square yards (sq yd, 

yd2

) 

1 square kilometer (km2

) = 0.4 square mile (sq mi, mi2) 

0,000 square meters (m2

) = 1 hectare (ha) = 2.5 acres

 

MASS - WEIGHT (APPROXIMATE)

1 gram (gm) = 0.036 ounce (oz)

1 kilogram (kg) = 2.2 pounds (lb)

1 tonne (t) = 1,000 kilograms (kg)

 = 1.1 short tons

VOLUME (APPROXIMATE)

1 milliliter (ml) = 0.03 fluid ounce (fl oz)

1 liter (l) = 2.1 pints (pt)

1 liter (l) = 1.06 quarts (qt)

1 liter (l) = 0.26 gallon (gal)

 

 

 

1 cubic meter (m3

) = 36 cubic feet (cu ft, ft3) 

1 cubic meter (m3

) = 1.3 cubic yards (cu yd, yd3)

TEMPERATURE (EXACT)

[(9/5) y + 32] °C = x °F

1

1

QUICK INCH - CENTIMETER LENGTH CONVERSION

0 1 2 3 4 5

Inches

Centimeters 0 1 2 3 4 5 6 987 1110 1312

QUICK FAHRENHEIT - CELSIUS TEMPERATURE CONVERSION

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

 °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
iii

Acknowledgments

The U.S. Department of Transportation (USDOT) 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 Signals, Train Control, and Communications Division, 

FRA, and Leonard Allen, Program Manager, Signals, Train Control, and Communications 

Division, FRA, for their guidance and direction in developing this report. 

The authors also wish to thank Daniel Lafontaine, Chief Engineering, Grade Crossing and 

Access Control Programs, Transport Canada (TC), and Daniel Blais of the TC Transport 

Development Centre for their cooperation and contribution of data that was used for this project. 

The authors would also like to acknowledge Marco daSilva, Highway-Rail Grade Crossing and 

Trespass Safety Research Program Manager, Systems Engineering and Safety Division, USDOT 

Research and Innovative Technology Administration’s John A. Volpe National Transportation 

Systems (Volpe Center), Anya A. Carroll, Principal Investigator of Surface Transportation 

Programs, Center of Innovation for Physical Infrastructure Systems, Volpe Center, John 

McGuiggin, Chief of the Systems Engineering and Safety Division, Volpe Center, and Glenn 

Goulet, Chief of the Infrastructure and Facility Engineering Division, Volpe Center for their 

leadership and direction.
iv

Contents

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

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

2 Discussion of Minimum Requirements and Cost .................................................................. 5

3 Analysis of Previous Research ............................................................................................... 8

3.1 Federal Experience.............................................................................................................. 8

3.2 Transporation Review Board ............................................................................................ 10

3.2.1 High-Speed Rail Innovations Deserving Exploratory Analysis Program............. 10

3.2.2 National Cooperative Highway Research Program .............................................. 11

3.3 States ................................................................................................................................. 13

3.3.1 Minnesota Experience ........................................................................................... 13

3.3.2 North Carolina ...................................................................................................... 16

3.4 Transport Canada Research .............................................................................................. 18

3.5 Australia ............................................................................................................................ 20

4 Current Research .................................................................................................................. 22

5 Impediments to Acceptance ................................................................................................. 24

5.1 Institutional ....................................................................................................................... 24

5.2 Cost ................................................................................................................................... 25

5.3 Technological .................................................................................................................... 25

6 Findings................................................................................................................................ 28

7 Recommendations ................................................................................................................ 30

References ..................................................................................................................................... 33

Appendix A. Sample Performance Criteria ................................................................................. 36

Abbreviations and Acronyms ....................................................................................................... 39
v 

Figures

Figure 1. Twenty-Year Incident Rate at Active and Passive Public Grade Crossings 

(Ngamdung, 2009b). ....................................................................................................... 3

Figure 2. Distribution of Grade Crossing Subsystem and Labor Costs (Petit, 2002) .................... 7

Figure 3. Detail of Road Crossing Showing Island Limits and Vehicle Detection Limits

for TTC Testing (Reiff, Gage, Caroll, and Gordon, 2003) ............................................ 9

Figure 4. Schematic Representation of Double-Wheel Sensor Axle Counter Test Layout

(Reiff, Gage, Caroll, and Gordon, 2003) ...................................................................... 10

Figure 5. Mn/DOT Grade Crossing Warning Lights (left) and Advance Warning Sign 

Lights (right) (URS and TranSmart, 2005) .................................................................. 14

Figure 6. EVA Signal System Corporation Warning Device Configuration as Tested in 

North Carolina (Jennings, Field, Worley, and Scott, 2005) ......................................... 17

Figure 7. TC Low-Cost Warning Device Configuration (Hildebrand, Roberts, and 

Robichaud, 2007) ......................................................................................................... 19
vi 

Tables

Table 1. FRA Grade Crossing Signal System Safety Regulations ................................................ 6

Table 2. Technologies Evaluated in TTI Research (Roop, Roco, Olson, and Zimmer, 2005) ... 12

Table 3. High-Level Performance Criteria Categories Defined by TTI (Roop, Roco, 

Olson, and Zimmer, 2005) ............................................................................................. 12

 
1 

Executive Summary 

Virtually all of the grade crossing train detection and warning systems in the United 

States use a variant of the track-circuit technology developed over a century ago. Track 

circuits have evolved through the years, but the design and principles of operation have 

changed little. Although highly reliable, these systems are costly to install at low-usage 

grade crossings. Systems that leverage cost-effective, nontraditional technologies are an 

attractive alternative. The challenge for the railroad industry is to develop systems that 

are economical and safe. 

In response to this challenge, the Federal Railroad Administration’s (FRA) Office of 

Research and Development directed the U.S. Department of Transportation’s (USDOT) 

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

Transportation Systems Center (Volpe Center) to conduct a technology assessment of 

low-cost active warning devices for application at passive highway-rail grade crossings. 

The objective of this research was to present an objective assessment of these 

technologies and recommend a course of action that would facilitate implementation in 

the United States. 

Although there is no “low-cost” threshold, the body of research has shown a range of 

5–30 percent of the cost for a conventional track-circuit–based grade crossing system. 

The large deviation was attributed to the variation in performance and functional 

requirements at each application. One of these is the location of the train detection and 

warning equipment, which has been developed for both on the right-of-way (ROW) or 

off-ROW environments. On-ROW systems are installed on railroad property and 

typically interface physically or electrically, with railroad infrastructure. Off-ROW 

systems are located external to railroad property and provide nonobtrusive train detection 

and warning functionality. 

Many innovative on-ROW and off-ROW prototype systems have undergone extensive 

testing in North America, Europe, and Australia. However, a variety of technical, 

economic, and institutional issues need to be overcome before these technologies are 

considered mature enough to be adopted by railroads and government regulatory 

agencies. In recent years, regulatory bodies have become increasingly sophisticated in 

their knowledge of nonconventional train detection and warning technologies. This is 

reflected in the growing use of performance-based regulations, which offer more 

flexibility for railroads and railroad suppliers to demonstrate safety. 
2 

1. Introduction

Passive highway-rail grade crossings account for approximately 50 percent of the total 

number of public crossings in the Unites States, according to USDOT’s FRA (2009a). 

Over the past 20 years, Federal, State, and local governments, as well as railroads, have 

succeeded in significantly reducing accident risk posed by passive grade crossings. The 

most successful strategy has been to close crossings wherever possible and to install

active warning devices at locations that cannot be closed under any circumstances. This 

is borne out in statistics maintained by FRA. 

Of the 178,000 public grade crossings in the United States in 1989, 120,000 or 67 percent 

were designated as passive in the FRA highway-rail grade crossing inventory. By 2008, 

this number was reduced by 40 percent to 71,000 or 52 percent of the 137,000 public 

grade crossings. Coincidentally, the number of active public crossings increased from 

58,000 to 66,000 over the same 20-year period (Ngamdung, 2009a). Other strategies, 

including innovative placement of stop and yield signs, have proven effective in reducing 

risk as well (Russell, Rys, and Liu, 1999). 

The plots in Figure 1 signify the 20-year decline in incident rates at passive and active 

grade crossings, where the incident rate data have been normalized with respect to traffic 

moment (T-M). Incidents at active grade crossings, denoted by the red line, decreased 

from approximately 9 per 100 T-M to 2 per 100 T-M, roughly equivalent to an 80 percent 

reduction. Meanwhile, incidents at passive crossings decreased in a similar fashion from 

85 per 100 T-M to 15 T-M, resulting in an 80 percent drop as well (Ngamdung, 2009b). 

Despite these successes, the incident rate for passive grade crossings still exceeds that of 

active ones by a factor of 10, and the magnitude ratio has not varied substantially. 

The decrease in the passive crossing incident rate reflects the concerted effort to either 

eliminate the riskiest crossings or upgrade them with active warning devices. The 

remaining group of passive crossings poses less of a risk but still requires serious 

attention. Working against this trend is the limited availability of Federal and State 

funding for crossing improvements as well as the competition with other highway 

improvement programs for funding. This has necessitated that grade crossings be 

prioritized for improvement in terms of risk and the funds allocated accordingly, resulting 

in slow but steady progress. This is the environment that forms the basis for low-cost 

warning device research.

Virtually all of the grade crossing train detection and warning systems in the United 

States employ a variant of the same basic track-circuit technology developed a century 

ago. In recent decades, railroads have migrated from relay-based control systems to 

those that are processor-based. However, the design and principles of operation have 

changed little. The procurement and installation cost of these traditional crossing 

systems is the primary impediment to more widespread deployment. According to a 

1995 U.S. General Accounting Office report, the average cost of installing flashing lights 

and gates was $150,000 (1995). If a modest 3 percent inflation rate is assumed, the 
3 

equivalent cost in current dollars is $230,000. This is an average value and can vary 

greatly depending on the complexity of the circuit logic, the type of warning device 

installed (flashing lights, gates, etc.), and the labor effort required. However, assuming 

that this is somewhat reflective of actual values, the cost to install flashing lights and 

gates at the 71,000 existing passive crossings would be approximately $16 billion. This 

is four times greater than the estimated $4 billion Federal and State investment in grade 

crossing improvements since the Rail-Highway Crossing Program began in 1974 (FRA, 

2009b). At these pricing levels, there is little benefit-cost justification for upgrading 

many passive grade crossings with active warning devices.

Figure 1. Twenty-Year Incident Rate at Active and Passive Public Grade Crossings

(Ngamdung, 2009b) 

This environment has fostered a great deal of interest and research in the viability of lowcost risk mitigation alternatives at passive grade crossings, many of which are located in 

rural areas of the country. A late 1990s National Transportation Safety Board (1998) 

report included among its recommendations the completion of standards development for 

applications of intelligent transportation systems (ITSs) at grade crossings and the 

installation of stop and stop ahead signs at all passive crossings. ITS solutions usually 

consist of an in-vehicle warning system that communicates directly with an approaching 

train. This architecture circumvents the need for traditional train detection and warning 

systems. Consequently, the ITS was considered to present a low-cost opportunity to 

provide some type of active warning at passive crossings. However, the requirement that 

all trains and motor vehicles be equipped has proven to be a difficult obstacle to 

overcome. Considerable research has been performed to characterize the safety benefits 

of supplementing the basic cross buck with stop and stop ahead signs. The efficacy of 

0

1

2

3

4

5

6

7

8

9

10

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Year

Incidents per 100 T-M

0

10

20

30

40

50

60

70

80

90

Incidens per 100 T-M

Active Crossings

Passive Crossings
4 

these signs has been debated for many years (Lerner, Llaneras, McGee, and Stephens, 

2002). However, recent research has shown that stop sign-controlled crossings provide a 

statistically significant 45 percent reduction in accident rate over cross buck-only 

controlled crossings (Millegan, Yan, Richards, and Han, 2009). This is a positive trend 

but still leaves the passive crossing accident rate at a much higher baseline than active 

crossings. 
5 

2. Discussion of Minimum Requirements and Cost

One of the most compelling discussions of low-cost warning devices was held at a forum 

associated with the 2001 National Highway-Rail Grade Crossing Safety Conference. 

This forum brought together an assortment of experts from railroads, suppliers, and 

researchers. Bill Peterson of the Burlington Northern Santa Fe (BNSF) railroad 

presented some unique insights into the railroad perspective. One of his key points 

related to the difference in motorist perception to grade crossing warning systems and 

highway traffic lights. When highway traffic lights at an intersection are dark, motorists 

know that they are required to reach a full stop and proceed only when the intersection is 

free of traffic. However, a motorist approaching an active grade crossing with darkened 

warning devices perceives this situation as safe to proceed without stopping, whether or 

not the equipment is functioning properly. 

The uniqueness of the grade crossing environment underscores the need to ensure that the 

warning devices are highly reliable and fail-safe. These requirements are expensive to 

satisfy and represent some of the primary roadblocks to the implementation of low-cost 

warning systems. Most other requirements, except for the cost associated with 

installation, dovetail from these two. For example, new active grade crossing systems 

require a new connection to the electrical power grid, typically at a cost of approximately 

$10,000. Although solar and wind power have been the subject of interest in recent 

years, the reliability of these systems, even with a battery or generator backup, is 

insufficient (Peterson, 2001). 

As presented by Moody and Reiff (2001) at the same forum, track-circuit–based grade 

crossing systems range in cost from $100,000 to $150,000. They suggested a range of 

$20,000 to $50,000 for low-cost warning devices with reduced features that would satisfy 

a minimum set of performance requirements as governed by the FRA regulation for grade 

crossing safety. These requirements include a minimum warning time of 20 seconds, 

incorporation of fail-safe operation principles, noninterference with existing systems and 

signals, and use of applicable design requirements found in the Manual of Uniform 

Traffic Control Devices (MUTCD), Parts 8 and 10. 

Annual maintenance costs, which are usually financed by the railroad, may be even more 

critical than initial system cost. For low-cost warning systems, these must be 

significantly less than for traditional grade crossing systems for the systems to still be 

considered “low cost” (Moody and Reiff, 2001). 

In 2002, the American Railway Engineering and Maintenance-of-Way Association

(AREMA) Committee 36, Highway-Rail Grade Crossing Warning Systems, published an 

analysis of baseline grade crossing system costs for evaluating the costs of current and 

future technologies. The objective of the analysis was to determine the relative cost of 

grade crossing subsystems and the related costs of design, engineering, and installation 

services (Petit, 2002).
6 

The first step of the analysis entailed identifying the minimum requirements, in terms of 

regulatory compliance and industry guidelines, that all grade crossing systems must 

satisfy. From the regulatory perspective, Title 49, Part 234 of the Code of Federal 

Regulations (CFR), Grade Crossing Signal System Safety, “imposes minimum 

maintenance, inspection, and testing standards for highway-rail grade crossing warning 

systems.” The maintenance, inspection, and testing standards are found in Part 234, 

Subpart D. The sections relevant to minimum requirements are shown in Table 1 below. 

Table 1. FRA Grade Crossing Signal System Safety Regulations 

These standards are quite rigorous and must be satisfied by any warning system, 

regardless of the cost. In its report, AREMA Committee 36 addressed all of these 

requirements, as well as industry best practices, to evaluate grade crossing system cost. 

The minimum requirements described above were used to develop a baseline cost 

allocation with the following attributes: 

• Single-track application with dual direction operation possible. 

• Warning devices consisting of entrance gates, flashing lights, and bells. 

• Train detection system with conventional track-circuit technology for uniform time 

warning. The approach circuit is approximately 3,000 feet in each direction, with an 

Section Description

234.203 All control circuits that affect the safe operation of a highway-rail grade 

crossing warning system shall operate on the fail-safe principle.

234.205 Operating characteristics of electromagnetic, electronic, or electrical 

apparatus of each highway-rail crossing warning system shall be 

maintained in accordance with the limits within which the system is 

designed to operate.

234.215 A standby source of power shall be provided with sufficient capacity to 

operate the warning system for a reasonable length of time during a period 

of primary power interruption. 

234.225 A highway-rail grade crossing warning system shall be maintained to 

activate in accordance with the design of the warning system, but in no 

event shall it provide less than 20 seconds warning time for the normal 

operation of through trains before the grade crossing is occupied by rail 

traffic.

234.227 (a) Train detection apparatus shall be maintained to detect a train or rail car in 

any part of a train detection circuit, in accordance with the design of the 

warning system.

234.275 This requires that grade crossing warning systems, subsystems, or 

components that are processor based, which contain new or novel 

technology, are required to comply with the safety and risk analysis 

requirements defined in 236, Subpart H. In this context, new or novel 

technology specifically refers to designs that do not use conventional 

track-circuit technology.
7 

island circuit overlay. Both nonredundant and redundant train detection systems were 

considered. 

• External event recorder. 

• Processor or relay-based independent controller for warning devices. 

• Full battery backup with 48 hours of capacity. 

• Equipment installed in a 6 × 6-foot bungalow. 

• Crossing not located close to another crossing, requiring communication 

between the two.

The relative cost distribution for nonredundant grade crossing systems is shown in 

Figure 2. As described by Petit (2002), installation, engineering, freight, and power 

service account for at least 50 percent of the cost of a grade crossing. Installation cost is 

typically considered fixed, because many railroads are bound by labor agreements to use 

railroad signal installers rather than outside contractors. This can range from roughly 25 

to 35 percent of the total cost of a grade crossing system. In contrast, the cost of grade 

crossing electronics, including the train detection, crossing controller, and event recorder 

subsystems, varies from 12.5 to 17 percent of the total system cost, depending on the 

level of redundancy required in the detection system. Train detection, which is 

frequently targeted for cost reduction in low-cost warning system research, accounts for 

no more than 11.5 percent of system cost.

Figure 2. Distribution of Grade Crossing Subsystem and Labor Costs (Petit, 2002)

0%

10%

20%

30%

40%

Housing

Batteries

Ground Material

Warning Material

Train Detection

Crossing Controller

Event Recorder

Assorted Electrical Equipment

Power Service

Engineering

Freight

Installation

Cost Categories
8 

3. Analysis of Previous Research

3.1 Federal Experience

The requirements presented by Moody and Reiff at the 2001 National Highway-Rail 

Grade Crossing Safety Conference were developed as part of a larger research program at 

FRA’s Transportation Technology Center (TTC) in Pueblo, CO. In this FRA research 

initiated in 1999, the Volpe Center and the Transportation Technology Center, Inc. 

(TTCI), evaluated the performance of non-track-circuit–based train and vehicle detection 

technologies (Reiff, Gage, Carroll, and Gordon, 2003). 

In February and March 1999, TTCI issued a Request for Technical Information (RFTI) to 

almost 300 prospective vendors who had participated in previous grade crossing testing. 

The RFTI was specifically written to solicit information for train detection alternatives to 

track circuits and identified the salient minimum performance and operating requirements 

for which products would be evaluated. These included:

• Minimum train approach warning time of 20 seconds

• Release of island detection within 2 seconds of train departure 

• Train detection speed regimen of 5–125 miles per hour (mph) (8–200 kilometers per 

hour (km/h)) 

Of the 20 proposals that were submitted, six finalists were selected by the evaluation 

team. Each company was required to install a prototype of its product for testing at TTC. 

The test site was not equipped with actual warning devices such as gates and lights. 

Instead, the output control signal was recorded. Each vendor was required to submit a 

reliability, maintainability, and life-cycle cost analysis. In addition, each vendor was 

required to provide a description of how its product was designed using fail-safe 

principles. 

Only five vendors submitted a product by the deadline defined in the RFTI, and only four 

included a train detection component. These consisted of: 

• Two systems using vibration and magnetic anomaly sensors 

• One using inductive loops 

• One using double-wheel sensors (axle counters) for train detection 

The test environment is shown in Figure 3.
9 

Figure 3. Detail of Road Crossing Showing Island Limits and Vehicle Detection 

Limits for TTC Testing (Reiff, Gage, Caroll, and Gordon, 2003) 

All three systems were designed to provide fail-safe functionality, as described by each 

respective vendor. In addition to the minimum performance requirements listed above, 

each system was evaluated in terms of successful detections, critical failures, missed 

detections, and nuisance or false alarms. These measurements were performed for both 

approach and island indication detection. The double-wheel sensor was the only system 

able to detect all of the approach and island activations with no failures, missed 

detections and false alarms. The test configuration, shown in Figure 4, consisted of six 

total double-wheel sensors, a redundant pair at each approach, and one on either side of 

the island approximately 20 feet from the crossing. In simple terms, the approach sensors 

were used for train detection and warning device activation, with the redundant sensors 

serving as backups in case the first ones were not working properly. As the train passed 

over the grade crossing approach, the sensors counted the number of axles and 

transmitted the result to the grade crossing controller. This process was repeated as the 

train passed over each of the island sensors. Once the last car had exited the crossing, the 

controller compared the approach and island axle counts. If the values were equal, the 

controller released the crossing and deactivated the warning devices. 

This technology is widely used in Western European countries in overlay (France) and 

stand-alone (Germany and Spain) configurations (Luedeke, Wagner, Carroll, and

Markos, unpublished manuscript). However, it has been received less favorably in the 

United States, mostly because of reliability concerns such as sensor spacing relative to 

wheel flanges, debris buildup on the magnetic components of the sensors, and damage 

resulting from ice, rocks, and dragging of equipment. In recent years, design 

improvements have shown promise in increasing wheel sensor reliability. Another, 

possibly more significant concern, is that railroads in the United States view the 

continuous detection characteristic of track circuits more favorably than the point 
10 

detection of wheel sensors (Roop, Roco, Olson, and Zimmer, 2005). This is particularly 

critical in the context of designing train detection systems that satisfy FRA grade crossing 

signal system safety regulations.

Figure 4. Schematic Representation of Double-Wheel Sensor Axle Counter Test 

Layout (Reiff, Gage, Caroll, and Gordon, 2003)

The authors of the report found many of the technologies to be promising. However, 

because this was a research program, they did not endorse any of them nor suggest how 

they may be implemented by the railroad industry (Reiff, Gage, Caroll, and Gordon, 

2003). This research was preceded by testing of island detection system alternatives to 

track circuits performed by the Association of American Railroads (AAR) in 1996. Four 

technologies were tested:

• Count-in/count-out using strain gages 

• Count-in/count using magnetic wheel sensors 

• Modification of the existing island circuit

• Combination of movement and infrared presence detection 

During preliminary testing, the infrared system was found to be inadequate in train 

presence detection reliability and was removed from the test program. The three 

remaining technologies were then tested at an active grade crossing test site on the CSX, 

BNSF, and Union Pacific railroads, respectively. All three systems were installed at each 

test site in parallel with the conventional grade crossing circuit. The results of this 

research showed that none of these technologies could reliably detect trains as well as 

track circuits. As a final note, the authors recommended that these technologies be 

monitored for improvements in reliability (Guins, Reiff, Gurule, and Gage, 1996). 

3.2 Transporation Review Board

3.2.1 High-Speed Rail Innovations Deserving Exploratory Analysis

Program

FRA has used its affiliation with the Transportation Research Board (TRB) to sponsor 

low-cost warning device research as part of a greater focus on enabling railroad 

technologies. One such mechanism was the Innovations Deserving Exploratory Analysis 

(IDEA) program, which targeted promising but unproven concepts with the potential to 
11 

advance surface transportation systems. In 1997, FRA began funding the High-Speed

Rail IDEA program in which research proposals are selected on the basis of their 

potential role in upgrading the existing U.S. rail system to accommodate operations up to 

100 mph (160 km/h) and beyond. Although low-cost grade crossing detection and 

warning systems were not a primary objective of this program, several concepts with 

potential application toward train detection were funded and completed. The 

technologies studied in this research included: 

• Buried fiber-optic cable

• Rail-mounted fiber-optic cable

• Microwave radar

The objective of the buried fiber-optic cable research, performed by the Texas 

Transportation Institute (TTI) and completed in 2001, was to determine its potential to 

provide an inexpensive, reliable alternative to conventional track circuitry for train 

presence and broken rail detection. However, an excess of environmental noise so 

severely constrained the detection range that the research was concluded after laboratory 

testing (Olson and Roop, 2003). Concurrently, the University of Illinois investigated the 

viability of installing fiber-optic cable directly to rail. This research, completed in 2001, 

was more successful in minimizing environmental noise than the buried cable project. 

However, the differences were not readily apparent and a host of other issues including 

cost and protecting the cable from damage remained (Chuang and Young, 2003). 

From 1997 to 2000, O’Conner Engineering, Inc., developed and tested a microwave 

Doppler radar system for train detection. The radar specification included a range of 

about 1 mile with a 2-foot resolution and the capability to detect approaching or departing 

trains at velocities up to 150 mph (240 km/h). O’Conner Engineering performed testing 

at a single-track and double-track grade crossing. However, the test suite did not include 

characterizing the ability of the radar technology to discriminate between two or more 

trains within the field of view. The results showed that the radar suffered from detection 

limitations specific to high-speed trains and grade crossings with curved or obstructed 

approaches (O’Conner, 2009). This technology was documented in a research report of 

low-cost warning devices published by TTI (Roop, Roco, Olson, and Zimmer, 2005). 

3.2.2 National Cooperative Highway Research Program

In 2004, TTI was funded by the TRB National Cooperative Highway Research Program 

to identify and assess low-cost, viable, active, warning system and component designs for 

highway-rail grade crossings. The first report stemming from this research was published 

in 2005. In the report, the TTI researchers evaluated 12 potential low-cost grade crossing 

warning device technologies against a set of cost and performance criteria they had 

developed. These technologies are listed in Table 2 on the next page, and the general 

performance criteria categories are shown in Table 3. A more detailed description of the 

sample performance criteria is provided in the appendix to this report. 
12 

Table 2. Technologies Evaluated in TTI Research 

(Roop, Roco, Olson, and Zimmer, 2005)

Technology On-ROW Off-ROW

Geophone √

Fiber-optic (rail) √

Fiber-optic (buried) √

Video imagery √

Radar (speed) √

Radar (speed and distance) √

Acoustic √

Pressure sensor √

Magnetic anomaly √

Infrared √

Laser (lidar) √

Ultrasonic √

Table 3. High-Level Performance Criteria Categories Defined by TTI

(Roop, Roco, Olson, and Zimmer, 2005) 

Objectives Criteria

Enhanced Safety

Fail-safe design

Provides 20-second advanced warning

Geometric flexibility

Reduced System Cost Installation cost

System life

Reliability

Failure rate

Redundancy

Simplicity

Disruption resistance

Known and controlled-for failure modes

Installability Ease of installation

Site preparation

Maintainability Ease of inspection and testing

Ease of repair

Compatibility Encroaches on railroad property
13 

In contrast to the AREMA Committee 36 research, TTI defined the baseline system as 

train detection and flashing lights and/or warning lights, but no gates. For this platform, 

TTI established several cost categories: (1) ultralow, less than $25,000, (2) low, $25,000 

to $50,000, and (3) moderate, $50,000 to $75,000 (Roop, Roco, Olson, and Zimmer, 

2005). This compares favorably with values suggested by Reiff and Moody (2001). 

The results of this research were divided between systems that were installed on the 

railroad (ROW) and off-ROW. The railroad industry aversion to risk, resulting from tort 

liability concerns, suggested that off-ROW systems may be easier to implement. 

However, the dichotomy between the on-ROW and off-ROW systems, especially in 

regards to safety, was significant. 

In terms of safety, the best performing ultralow-cost technologies were fiber-optic (rail) 

and fiber-optic (buried), both of which must be installed on railroad property. For the 

low-cost category, the pressure sensor and magnetic anomaly technologies received the 

highest safety rating. Both of these technologies are required to be installed on the ROW 

as well. Only in the moderate cost category were two off-ROW technologies, ultrasonic 

and radar, found to rank highest overall. The off-ROW technologies, specifically the 

acoustic, ultrasonic, and radar, fared considerably better in the reliability rankings. 

In the next phase of this research, conducted in 2006, TTI tested the radar and acoustic 

detection systems at a four-quadrant gate crossing in College Station, TX. These 

technologies were selected because they could be installed off-ROW and not be 

constrained by railroad liability issues. The equipment for both systems was mounted on 

a city traffic light utility pole at a height of 14 feet above the ground and 20 feet from the 

nearest rail. For the radar system, an antenna was installed on the utility pole to detect an 

approaching train in either direction, and a single antenna was installed for island 

detection. The radar technology was capable of train detection and speed measurement. 

The acoustic system consisted of a single omnidirectional microphone for detection of 

locomotive train horns and was only capable of train detection. 

The performance of each of these technologies was compared with the track-circuit 

signaling system that was already installed at the grade crossing and was recorded in 

shadow mode. The data collection period, 76 days between August and October 2006, 

consisted of approximately 1,500 track-circuit activations by approaching trains. Both 

systems detected 100 percent of the trains but were much less successful at discerning rail 

from highway traffic. This was marked by the high false train detection rates shown by 

both systems, 57 percent for the radar system and 94 percent for the acoustic system. 

Although the radar system demonstrated more potential, neither was considered robust 

enough to satisfy railroad liability concerns in spite of being installed off-ROW.

3.3 States

3.3.1 Minnesota Experience

From 2001 to 2005, the Minnesota Department of Transportation (Mn/DOT) developed 

and deployed a low-cost warning system on the Twin Cities and Western Railroad

(TC&W). The objective of this program was to compare the performance of this 
14 

technology with that of traditional track-circuit–based warning devices at grade crossings 

with few train movements and highway users. Mn/DOT defined “low cost” as $10,000 to 

$15,000, or the equivalent to 10 percent the cost of a conventional grade crossing 

warning system (URS and TranSmart, 2005). 

In contrast to the wayside-centric functionality of most train detection and warning 

systems, this system was locomotive-centric. One of the core features of this type of 

system was that each equipped locomotive resolved its location as well as the location of 

all grade crossings. This was accomplished by means of a global positioning system 

(GPS) receiver installed on every locomotive. Another core feature was the use of 

wireless radio technology for communications between locomotives and grade crossings. 

Although gates were not installed at any of the grade crossings, they were all upgraded 

with the traditional cross buck-mounted flashing lights facing each direction of oncoming 

highway traffic, as shown in Figure 5. As an added safety measure, an active warning 

sign, connected to the warning system, was installed on each approach lane in advance of 

the crossings, also shown in Figure 5. All of the crossing equipment, including the 

controller, was powered by a 14-volt battery with a solar panel charging system (URS 

and TranSmart, 2005). 

Figure 5. Mn/DOT Grade Crossing Warning Lights (left) and Advance Warning 

Sign Lights (right) (URS and TranSmart, 2005) 

Unlike wayside-centric systems, train detection was performed by the onboard 

locomotive equipment. In this multistep process, the GPS receiver, in conjunction with a 

dead reckoning system, determined locomotive location, travel direction, and speed. The 

onboard equipment used these data to resolve the locomotive position with respect to 

nearby grade crossings and calculated an estimated time to arrival. This was performed 

dynamically and therefore provided for grade crossing warning device activation using a 

constant warning time (CWT) algorithm. Train detection was ultimately achieved by 
15 

transmitting this information to the grade crossings. Although all grade crossings within 

5 km of the locomotive receive the data, only crossings within 2 km were authorized to 

be activated. Because CWT was calculated on-the-fly, the grade crossing controller was

programmed to activate the warning devices using a preset warning time as long as it 

meets the 20-second minimum requirement (URS and TranSmart, 2005). 

Island detection was accomplished by an integrated magnetometer and ultrasonic sensor 

unit installed on each cross buck. The magnetometer was responsible for primary train 

detection in the island, whereas the ultrasonic sensor was used to confirm the 

magnetometer output. This subsystem was designed to operate independently of the 

train-borne detection and activation equipment and was not considered to be a primary 

crossing activation device (URS and TranSmart, 2005). 

The train to grade crossing radio network was designed on the shared network model and 

operated in the 220-megahertz ITS dedicated frequency band. Because the network was

shared, multiple locomotives and grade crossings were supported. The one-way 

transmission range of the radio equipment was 5 km and allowed for locomotive and 

grade crossing equipment to establish a data exchange up to that limit. However, only 

crossings within a 2 km approach could be activated (URS and TranSmart, 2005). 

If there was a system error involving the function of the locomotive or the grade crossing 

equipment, or difficulty establishing data communications between a locomotive and the 

crossing equipment, the crew was notified by a display and audible warning. The crew 

would then be required to stop the train on the crossing approach and manually flag the 

crossing (URS and TranSmart, 2005). 

In total, 27 passive grade crossings on a 75-mile corridor of the TC&W between Cologne 

and Renville, MN, were equipped with the low-cost warning device system. Between 

April 2003 and November 2004, Mn/DOT incrementally installed and tested the grade 

crossing equipment, equipping 10 crossings first. After extensive shadow mode testing, 

the final 17 crossings were equipped and programmed to operate in shadow mode. 

The field operational test (FOT) was performed during an 80-day span from June to 

September 2005 under a waiver from FRA. Six of the 27 crossings were operated in 

active mode. The remaining 21 crossings were operated in shadow mode and thus 

transparent to motorists. After the FOT was completed, the warning system was removed 

from all of the 27 crossings. 

The results of this research, published in December 2005, indicated that no system failure 

was reported during the FOT. The active warning system accurately warned and 

provided adequate warning times to motorists for approaching trains. The research 

findings were submitted to FRA as part of the waiver and approval process (URS and

TranSmart, 2005). 

Although the overall highway rail interface HRI system offers great potential to a lowcost alternative, TC&W never demonstrated compliance with the FRA regulation for fail-
16 

safe grade crossings control circuitry, specifically train detection. In the initial waiver of 

compliance, TC&W sought regulatory relief from 49 CFR Part 234.203, which requires 

that all control circuits that affect the safe operation of a highway-rail grade crossing 

warning system shall operate on the fail-safe principle. In the waiver request, TC&W 

stated that the train detection system was not track-circuit based and thus not in strict 

compliance with the regulation. Rather, the railroad claimed that they complied with the 

“spirit and intent” of the regulation by means of a non-track-circuit–based train detection 

subsystem (FRA, 2002). 

3.3.2 North Carolina

Between October 2001 and September 2003, the North Carolina Department of 

Transportation (NCDOT) tested a magnetometer-based train detection and warning 

system. Magnetometer technology is used to detect changes in the ambient magnetic 

field of the earth associated with the presence of a large mass iron, such as an 

approaching train. The technology, developed by EVA Signal System Corporation, was 

selected by NCDOT for several reasons. First, the EVA product offered a combination of 

lower cost and unique features not matched by the other systems evaluated by NCDOT. 

Second, the magnetometer technology was designed for off-track train detection and 

completely independent of the track circuitry. Finally, the technology was marketed as 

fail-safe by EVA Signal (Jennings, Field, Worley, and Scott, 2005). 

The objectives of the test were to test the ability of the EVA system to detect trains 

reliably and accurately, test the ability of the systems to communicate effective warnings 

to motorists, and study the reaction and behavior of the public to the experimental signal. 

The equipment was installed at a grade crossing on the North Carolina and Virginia 

Railroad (NCVARR) near Rich Square, NC. From October 2001 to July 2003, the EVA 

1000 system was tested (Jennings, Field, Worley, and Scott, 2005). 

The warning system consisted of a traditional cross buck with flashing red light-emitting 

diodes (LEDs) in an “X” pattern, a flashing strobe light bar mounted 5 feet above the 

cross buck, and a train detection advisor mounted under the strobe bar, consisting of six 

sequentially activated yellow halogen lights to provide motorists with the direction of an 

approaching train. The whole grade crossing system was battery powered by three 

12-volt batteries with an optional solar recharging system (Jennings, Field, Worley, and 

Scott, 2005). The configuration is shown in Figure 6. 

The initial train detection configuration consisted of six magnetometer sensor probes 

buried in the railroad ROW adjacent to the NCVARR track. The probes were installed in 

the following arrangement on either side of the crossing: 

• One at 1,690 feet (512 meters)and another at 1,590 feet (482 meters) from the 

crossings for calculation of train velocity 

• One for verification of train movement at 1,000 feet (303 meters) from the crossing 

• One for island activation at 50 feet (15 meters from the crossing) 

• Two probes for backup detection at 1,540 feet (467 meters) and 150 feet (45 meters) 

from the crossing (Jennings, Field, Worley, and Scott, 2005) 
17 

Figure 6. EVA Signal System Corporation Warning Device Configuration as Tested 

in North Carolina (Jennings, Field, Worley, and Scott, 2005) 

The sensor probes were hardwired by a buried cable to a control unit adjacent to the 

crossing, which was housed in a waterproof underground vault. The control unit 

employed the signals from the first two sensors to calculate train velocity and time to 

train arrival at the crossing. This provided CWT functionality and adequate warning 

times for the motorist. A pair of infrared sensors was installed at the crossing itself to 

verify train presence. These sensors were mounted to steel posts on either side of the 

crossing and were aimed diagonally across the tracks (Jennings, Field, Worley, and 

Scott, 2005). 

From the outset of the testing, the EVA 1000 system was constantly plagued by 

operational issues, primarily from false activation of the warning devices and low island 

detection reliability. Although EVA Signal and NCDOT worked diligently, these issues 

could not be resolved. The high false activation rate was found to result from the 

inability of the magnetometer probe sensors to discriminate trains from maintenance-ofway (MOW) equipment and all-terrain vehicles (ATVs). EVA offered fencing as a 

possible solution for the ATV issue but does not seem to have ever been implemented by 

NCDOT or the railroad. In any case, this would not have resolved the false activations 
18 

attributed to the MOW equipment. In July 2003, the crossing was upgraded with the 

EVA 3000 system that featured an improved island detection module. However, the test 

program was terminated before the effectiveness of the new island detection module 

could be evaluated. The low reliability of the technology precluded the third objective of 

the program, the driver behavior study, from ever being initiated (Jennings, Field, 

Worley, and Scott, 2005). 

3.4 Transport Canada Research

From April 2005 to March 2007, the University of New Brunswick (Canada) evaluated a 

radar-based low-cost warning device system for private and farm crossings. This 

evaluation was unique to the others described in this report in that the test site was not an 

actual grade crossing, but rather a section of track. In this manner, the research team 

could measure the performance of the detection and warning device equipment without 

interfering with motor vehicle traffic. The actual test occurred in Grand Bay-Westfield, 

New Brunswick, on the New Brunswick Southern Railway, near St. John, New 

Brunswick. At the time of the testing, the line experienced a train frequency of 50–60 

trains per month. With hi-rail vehicle traffic included, the total rail-borne movements

could range from 60 to 90 trains per month (Hildebrand, Roberts, and Robichaud, 2007). 

At the time the research was performed, passive private and farm road crossings were not 

under the regulatory control of Transport Canada (TC). However, a crossing that is 

upgraded with active warning devices falls within the jurisdiction of the TC grade 

crossing regulations. In a slight variation of the U.S. grade crossing safety regulations, 

TC regulations reference AAR (now AREMA) recommended practices for design and 

operational requirements for signals, gates, operating mechanisms, and control circuits. 

Likewise, the recommended practices require that these components be designed on the 

fail-safe principle (Hildebrand, Roberts, and Robichaud, 2007). 

The system included train detection and warning device functionality. Like the other 

systems described thus far, there was a separate system for both train approach and island 

presence detection. A dual scanning X-band Doppler radar, one facing each direction of 

train travel, was used to detect both approaching and departing rail traffic. The radar 

operated in the 10.5-gigahertz band and had an adjustable detection range of 250–3,000 

feet (76–909 meters). A single ultrasonic sensor, operating in the 50-kilohertz band was 

responsible for island presence detection. The warning devices consisted of electronic 

bells and flashing LED lights. The entire system was powered by two 120-ampere 

batteries supported by three 80-watt solar panels. All of the equipment, including the 

sensors, was mounted on a single pole on the ROW (Hildebrand, Roberts, and 

Robichaud, 2007). 

The system, shown in Figure 7, was installed in April 2005 and field-tested through 

March 2007. Because no commercial low-cost warning device technology was available, 

the system tested was a prototype in shadow mode. The evaluation criteria consisted of 

assessing the system performance with respect to the train detection components, warning 

time adequacy, and solar panel power system effectiveness and reliability. Specific 

parameters that were captured included total number of system activations, duration of 
19 

activations, missed detections, and clearance times (Hildebrand, Roberts, and 

Robichaud, 2007). 

Figure 7. TC Low-Cost Warning Device Configuration 

(Hildebrand, Roberts, and Robichaud, 2007) 

High false train detection and missed activation rates were a constant issue throughout 

the entire system testing process, especially during initial testing. These were attributed 

to either the radar system detection software algorithm, which resulted in over- or 

undercalibration of the detection sensitivity, or faulty operation of the radars themselves. 

The software sensitivity issue was resolved by a series of four firmware updates, with the 

final implementing an adaptive detection algorithm. However, the reliability of the radar 

units remained a constant concern, with two failing during the 2-year evaluation period. 

Overall, the system showed some potential, but it is still not reliable and robust enough to 

be used as stand-alone active warning system in the United States. In addition, it does not 

incorporate fail-safe operation (Hildebrand, Roberts, and Robichaud, 2007). 

A unique feature of this platform is that the manufacturer ships it preassembled, with the 

exception of the solar panel. This type of platform could potentially yield significantly 

reduced savings in installation related labor costs (Hildebrand, Roberts, and 

Robichaud, 2007). 
20 

3.5 Australia

In the early part of 1999, the State of Victoria started a trial of a low-cost warning device. 

The main objective was to develop a system that would cost about 1/10th of a 

conventional active system, be fail-safe, and most importantly, make the passive crossing 

conspicuous at the time a train is approaching the crossing. Five devices, consisting of a 

Doppler radar unit, two magnetometers, an in-train transmitter, and an electromagnetic 

induction loop, were screened based on reliability of train detection. The devices were 

installed on an abandoned section of track and subjected to approximately 500 passes by 

a hi-rail vehicle. The highest reliability technology, the electromagnetic induction loop, 

was selected for further testing (Jordan, 2006). 

The system was tested over 1 week on an abandoned section of track using a road 

transferable locomotive. The test configuration consisted of a pair of inductive loop 

detectors installed between the rails and on top of the railroad ties 16.5 feet (5 meters) 

apart and approximately 2000 feet (606 meters) from the crossing. The detector pair 

added a measure of redundancy to the detection process but also allowed for calculation 

of train velocity. 

A third detector installed at the crossing served a dual purpose: (1) turn off the flashing 

lights once a train has departed the crossing and (2) a redundant detection in case the first 

two detectors failed to detect a train. The signal from the detectors was transmitted to a 

grade crossing controller at the crossing by a very high frequency radio link. The 

controller used a CWT algorithm to calculate the train velocity and to activate the 

warning devices for 25 seconds, accordingly. A diagnostic remote monitoring system 

was later added to the grade crossing controller (Jordan, 2006). 

After two successful trials, the system was installed at a passive crossing in Victoria for 

shadow mode testing. The equipment was powered by a solar generator. The active 

warning device, shown in Figure 8, consisted of a pair of flashing lights mounted on an 

Australian advanced warning sign installed 165–660 feet (50–200 meters) from both 

approaches to the crossing. As of 2006, the test results had not been published, but the 

authors stated that a revenue service test was forthcoming. The overall cost of the system 

was estimated to be in the order of one-fifth of the cost of a conventional active level 

crossing (Jordan, 2006).

During the trial period, several issues unrelated to the technology arose that influenced 

the selection of the electromagnetic induction loop technology: legal liability and the 

perception that government was trying to save money. “The legal advice received at the 

time took the view that the technology used had to be well tested, subjected to rigorous 

risk assessments, and applied in a professional manner. If this was done, it was 

concluded that a Court of Law would most likely have little reason to fine against the 

new device, all other matters being equal” (Government of Victoria, 2008). 
21 

Figure 8. Australian Advanced Warning Sign (Jordan, 2006)
22 

4. Current Research

In 2006, TC initiated a low-cost warning device research effort that was complementary 

to the research described in Section 3.4 above. The project began in 2006 and consists of 

two phases. The first, completed in 2007, comprised an analysis to identify potential 

solutions and an evaluation by a technical steering committee, resulting in selection of the 

two most promising technologies for testing. Phase 2, which is an ongoing effort, 

involves the acquisition, installation, and testing of the two candidate systems. The 

Canadian provinces of Quebec and Saskatchewan expressed interest in this research, and 

as such, a crossing in each province was selected for testing one of the low-cost warning 

systems (TC, 2007). 

The two-phase process used by TC closely follows the methodology used by FRA/Volpe

Center in the evaluation of alternative detection devices previously described. First, TC 

invited the North American grade crossing supplier industry to present its technologies, 

using the following general requirements:

• Cost between $10,000 and $30,000 Canadian

• Provide an optimal level of safety and reliability

• Operate independently of the railroad infrastructure with no onboard locomotive 

equipment or interconnection to the traditional railroad circuitry

• Be independent of the electrical grid

• Alert the locomotive crew to health of the grade crossing with sufficient advanced 

notice so that the crew can react appropriately and safely (TC, 2007) 

Of the 20 companies that responded to the invitation, 11 were found by the steering 

committee to offer a system satisfying the specification and were invited to present their 

technology to the committee. As of this writing, only one system, manufactured by 

Carmanah Technologies Corporation, has been selected for testing. The train detection 

technology operates on the same physical principles as the EVA signaling product by 

measuring changes in the ambient magnetic field of the earth. However, instead of offtrack magnetometers, a pair of triple-axis magnetoresistance detectors was installed at 

each approach to the crossing. Similarly, a pair was installed at each island entrance. 

The magenetoresistance detectors transmit occupancy information to the crossing control 

equipment by means of wireless radios. The warning system uses LED warning, and the 

entire crossing system is solar powered. If any of the detectors or radios fails, the 

warning devices are automatically activated (TC, 2007). 

The minimum performance criteria for this system were defined by the steering 

committee as:

• Minimum 20 seconds of warning time 

• Stop detection at the platform less than 2 seconds after train departure 

• System operation over a speed regiment from 5 to 125 mph (8–200 km/h) (TC, 2007)
23 

As with the FRA/Volpe Center alternative detection technology research, three types of 

failures were defined: critical, missed detection, and nuisance/false alarms. A critical 

failure was defined as a warning time of less than 20 seconds, system deactivation prior 

to train departure from the platform, and system deactivation greater than 10 seconds 

after train departure. Although a missed detection is self-explanatory, nuisance/false 

alarms consisted of any activation of the crossing warning system not resulting from a 

train (TC, 2007). 

As of 2009, the Carmanah system was currently under evaluation at a private grade 

crossing in Saguenay, Quebec. A traditional active warning system was installed in 

parallel so as to compare the two technologies simultaneously. If the test results show 

that the system is highly reliable, TC will pursue a system failure analysis to evaluate 

how well it satisfies fail-safe operational principles. 
24 

5. Impediments to Acceptance

5.1 Institutional

As alluded to previously, tort liability remains the number one impediment to the 

implementation of low-cost warning devices at passive grade crossings. Two sections of 

the FRA Grade Crossing Signal System Safety regulation, 234.03 and 234.275, reinforce 

the complexity of the issue. Section 234.03 requires all grade crossing control circuits to 

operate on the fail-safe design principle. With over 100 years of field experience and 

millions of activation cycles, conventional train detection track circuits have been 

deemed essentially fail-safe by FRA, railroads, and suppliers. However, demonstrating 

that new technologies are fail-safe is difficult, especially at the low end of the cost 

spectrum. Low-cost warning technologies may be reliable, but low-cost, high-reliability, 

and fail-safe operation tend to be mutually exclusive features. 

Section 234.75 requires non-track-circuit–based train detection technologies to comply 

with the safety and risk analysis requirements defined in 236, Subpart H, Standards for 

Processor-Based Signal and Train Control Systems. This is stated clearly in section 

234.275 (e), where deviation from the fail-safe design requirement “...must be separately 

justified at the component, subsystem, and system level using the criteria of Section 

236.909.” Section 236.909, the minimum performance standard for products covered by 

Subpart H, requires that the introduction of such products does not result in risk that 

exceeds the previous condition. In the low-cost warning device domain, this means that 

the inherent risk associated with any new technology cannot surpass the risk of the 

preexisting passive crossing. The argument outlined above, notably the mutual 

exclusivity of low-cost, highly reliable, and fail-safe features, is equally applicable to 

proving that there is no increase in risk resulting from any new technologies. 

The implication of these regulations is borne out by the reluctance of private or public 

sector entities to assume the liability associated with low-cost warning systems. As a 

result, the prevailing wisdom is that the tradeoff between cost and risk is too large and 

produces a negative cost-benefit curve.

The rational for Parts 234 and 236 most likely evolved from the legal discipline known as 

tort law. Tort law addresses, and provides remedies for, civil wrongs not arising out of 

contractual obligations. Although some categories of tort law deal with intentional 

wrongs, the relevant issue for grade crossings relates to unintentional wrongs or 

negligence. In this context, negligence is defined as conduct that falls below the 

standards of behavior established by law for the protection of others against unreasonable 

risk of harm. A person has acted “negligently” if he or she has departed from the conduct 

expected of a reasonably prudent person acting under similar circumstances. The 

hypothetical reasonable person provides an objective by which the conduct of others is 

judged. The key is that in tort law the reasonable person is not an average person or a 

typical person. Instead this person is a composite of what the community regards as to 

how the typical member should behave in situations that might pose a threat of harm to 

the public. In addition, the standard of conduct by which a person is judged is based on 
25 

the activity or profession in which he or she is engaged. For example, the standard of 

conduct for a railroad signal engineer is compared with the conduct of a skilled, 

competent, and experienced railroad signal engineer (Ogden, 2007). 

Liability for collisions occurring at grade crossings is governed by the law of negligence. 

Although tort law requires public agencies and railroads to exercise reasonable care to 

avoid injury to persons using the highway, they are not compelled to provide absolute 

safety. However, the potential for liability as a result of grade crossing collisions is a 

strong deterrent to testing and implementing new technology that deviates from 

conventional track circuit signaling systems (Ogden, 2007). 

5.2 Cost

As described previously in this report, cost is one of the most difficult pieces of the lowcost warning device puzzle to solve. The primary reason is that low-cost, high-reliability, 

and fail-safe operation is almost always mutually exclusive properties. The procurement 

and installation costs must be sufficiently low to justify the investment. This is especially 

so at crossings with low-rail and highway traffic volumes. Although there is no 

established cost threshold, the research presented in this report suggests a range of 5–30 

percent of the cost for a conventional track-circuit–based grade crossing system. The 

wide range in cost is attributable to the variation in performance requirements and the 

complexity of the failure analysis. 

The labor expense associated with installation is typically 25–35 percent of the total 

system cost, as previously discussed in this report. This is not a trivial amount of money 

because it constitutes twice that of the train detection and warning device electronics. If, 

hypothetically, it were possible to completely eliminate the train detection and warning 

device expenses, the overall cost would still be 65–75 percent of a traditional grade 

crossing system. 

Higher cost is also a consequence of the regulatory and legal barriers depicted earlier in 

this section. Decades of tort law precedent have produced a culture of risk aversion in 

the railroad industry. As a result, the industry is extremely reluctant to accept 

technologies that do not have a proven history of high reliability and safety. This is the 

current environment in which states or railroads are willing to invest large sums of money 

to reduce risk at grade crossings where the return on investment or benefit to society can 

be justified. However, the reality of limited funding precludes many passive public and 

private industrial crossings from receiving appropriate protection, either permanently or 

until the occurrence of a tragic accident. 

5.3 Technological

Fail-safe operation is the overriding requirement for any active grade crossing system, 

regardless of the cost or application. Grade crossing train detection and warning systems 

are a subset of the larger family of safety-critical systems. Although many promising offtrack and on-track low-cost grade crossing technologies have been evaluated, none has 

come close to satisfying the fail-safe operational requirement in the FRA Grade Crossing 

Signal System Safety regulations. 
26 

Many vendors claim that their system is designed in accordance with fail-safe operational 

principles. However, the definition of fail-safe is very specific and pertains to a design 

philosophy applied to safety-critical systems such that the result of hardware failure or 

the effect of software error shall either prohibit the system from assuming or maintaining 

an unsafe state or shall cause the system to assume a state known to be safe. Thus, 

demonstrating that a system is fail-safe is not trivial and can be costly. 

The process of establishing that products designed solely from discrete mechanical or 

electrical components are fail-safe is usually rather straightforward. The probable failure 

modes of these systems can be analyzed exactly to ensure that a failure will not result in 

an unsafe condition. As such, these systems are referred to as intrinsically fail-safe. 

However, in recent years, processor-based technologies have gradually supplanted 

systems built solely from discrete components, and many contain a combination of both. 

This necessitates the use of a formal risk assessment methodology, which can be rather 

rigorous in nature. Although this methodology is also performed on discrete components, 

processor-based systems, which contain hardware and software components, are much 

more complex and require a much more thorough analysis. The primary steps in this 

process explained briefly below are summarized from 49 CFR Part 236, Standards for 

Development and Use of Processor-Based Signal and Train Control Systems, 

Appendix D: 

• Preliminary hazard analysis (PHA) – follows or is performed in conjunction with the 

initial description of system requirements.

• Hazard analysis – focuses more on the detailed functions of the product and its 

components; an extension of the PHA performed in the later phases of product 

development. 

• Fault tree analysis – identifies all hazards and determines their possible causes. 

• Failure modes and effects analysis (FMEA) – considers the failure of any component 

within a system, tracks the effects of the failure, and determines its consequences. 

FMEA is particularly good at detecting conditions where a single failure can result in 

a dangerous situation. FMEA involves much detailed work and is expensive to apply 

to large complex systems. 

• Failure modes, effects, and criticality analysis – an extension of FMEA that identifies 

the areas of greatest need.

The FRA grade crossing regulations are quite exacting in this respect, especially with 

regard to new or novel technologies as specified in 49 CFR 234 Section 234.275. This 

specifically applies to processor-based systems control systems not recognized for use 

prior to March 7, 2005, when 49 CFR Part 236 was issued, including non-track-circuit–

based train detection and warning technologies. Many of the train detection technologies 

reviewed in this report are low cost in their commercial-off-the-shelf type. However, 

adding the appropriate safeguards to satisfy the safety regulations and reliability 

requirements for grade crossing and train control systems may negate any initial price 

advantage.
27 

Reliability is frequently expressed in terms of mean time to failure. No detailed 

reliability values for grade crossing systems are specified in Federal regulations or 

railroad industry standards. Nevertheless, the railroad industry demands extremely high 

reliability from equipment that is critical to dependable revenue service operations. 

Although not necessarily a safety metric, reliability can be associated with safety under 

certain circumstances. For example, they are both components of mean time to 

hazardous event assessment, which is the measure of time likely to pass before the 

occurrence of a hazardous event.

Some of the basic technical concerns were presented in this section. However, the reality 

is that except for wayside wheel detector technology, none of the low-cost warning 

systems reviewed in this report approach the safety and reliability of track-circuit–based 

detection and warning systems. That being said, some are closer to implementation than 

others. 
28 

6. Findings

Conventional, track-circuit train detection and warning systems have a long history as the 

industry-accepted standard for grade crossing control systems. The superior performance 

and operational characteristics of these systems pose a real threat to the development of 

low-cost technologies that are non-track-circuit dependent. The challenge for the railroad 

supplier industry is to ensure that the safety and reliability of these non-track-circuit 

technologies are not compromised while still maintaining low cost.

This goal may be achievable because the term “low cost” is subjective and is highly 

dependent on a variety of factors. These include how the baseline grade crossing 

warning device cost is defined, the cost threshold defined by the user, the requirements 

specific to the application, and the complexity of the application. Consider that the 

technologies described in this report ranged from 10 to 30% of the baseline cost. 

Installation of grade crossing infrastructure is the largest single-cost driver for traditional 

grade crossing systems. This includes trenching and connecting to the local utility grid, 

which can be expensive if no connection is available on-site. This necessitates a robust 

solar power system capable of supporting the train detection and warning device 

equipment. 

The wayside wheel detector technology has shown the most promise and is probably 

closest to achieving acceptance by the railroad industry. This does not imply, however, 

that the other technologies are not potentially viable with additional research and 

development. For one thing, the wayside wheel detector system may not ultimately be 

the lowest-cost technology, especially over the long term. In addition, the objective of 

this research was to present an objective assessment of the available low-cost warning 

device technologies and recommend a migration path that would facilitate their 

implementation.

The technologies described in this report fall into one of two categories—on-ROW or 

off-ROW. Although off-ROW systems are less problematic to install, they tend to be less 

safe and reliable than those that are on-ROW. The wheel detector is an on-ROW 

technology that has already been shown to be fail-safe and vital.

The institutional impediments to acceptance of low-cost grade crossing warning devices 

have proven to be the most intractable. Cost control, which cuts across all aspects of this 

research, is the underlying theme in this report. Reducing cost is a fundamental 

requirement, because low-cost, high-reliability, and inherent fail-safe operation are as a 

rule mutually exclusive. However, the reader should keep in mind that locations where 

external factors such as highway traffic, rail traffic, and/or accident frequency is 

intolerably high, cost is not a factor. The focus of low-cost warning device research is to 

lower the risk at passive grade crossings that are marginally risky, and the installation of 

conventional warning devices cannot be justified on safety alone.
29 

Although not likely, there is the possibility of a technological breakthrough resulting in a 

reduced cost structure for these systems and a high level of reliability and safety. As 

research in this field is always evolving, this outcome cannot be ruled out. However, as 

pointed out earlier, labor and installation costs tend be rather fixed. Also, the attempts to

find the so-called low-cost/high-reliability and safety “sweet spot” have been 

unsuccessful. 

Cost is an all-encompassing element that dovetails directly into the other institutional 

impediments—technology acceptance and reliability/safety. The precedent in the tort 

law system in the United States has been long established, and there is little likelihood for 

change in the foreseeable future. Although not perfect, conventional track circuits are the 

accepted technology for train detection and warning systems at grade crossings. If a 

passive grade crossing is upgraded with non-track-circuit–based technology, the new 

system must at a minimum be at least as safe as conventional track circuits. In addition, 

when a passive crossing is upgraded with active devices, the burden of responsibility for 

train detection transfers from the motor vehicle user of the crossing to the railroad. In 

light of these two concepts, there is little incentive for the railroad industry to innovate 

and a great deal of downside risk. Thus, the same modern-day legal system that requires 

safety-related industries to design and build a system to the most stringent safety 

requirements also lacks the flexibility to allow the introduction of many new, potentially 

life-saving technologies. 

The final piece of the puzzle is demonstrating that a new technology is fail-safe and 

reliable. Historically, the safety assurance logic for track-circuit–based train detection 

and warning has resided in electromechanical relays. These devices are renowned for 

simple design, highly reliable operation, and few but very well understood failure modes. 

In recent years, relays have been supplanted by processor-based systems, with similar 

underlying logic. FRA has monitored these systems for years and has incrementally 

increased its confidence that these systems are indeed safe and reliable, thus allowing 

many of theme systems to be “grandfathered-in.” 

By contrast, the low-cost warning device technologies in this research deviate 

significantly from traditional track circuit design and operation. Although the designs of 

these systems vary in complexity, the failure modes are not well understood. Also, FRA 

regulations, most notably 49 CFR 234.275, specify well-defined performance standards 

for new non-track-circuit–based technologies. Although a coherent approval process is 

now in place, the level of effort required by the railroad supplier industry to show that 

these technologies are safe and reliable probably outweighs the potential monetary 

benefits.
30 

7. Recommendations

Leverage Regulatory Efforts to Break Down Institutional Barriers

The chance that technological innovation will create the “magic bullet” that provides the 

industry with a low-cost, highly safe, and reliable grade crossing technology is an 

unlikely prospect. One alternative is to reduce the legal and regulatory burden on 

railroads and railroad suppliers. The solution may reside in an amendment to Title 49 of 

the U.S. Code known as the Rail Safety Improvement Act (RSIA) of 2008, signed into 

law by President George W. Bush in October 2008. Section 210 of the RSIA, Fostering 

Introduction of New Technology to Improve Safety at Highway-Rail Grade Crossings, 

supplies regulatory relief to railroads and suppliers. The authors of the amendment 

recognize that “the emergence of new technologies” may potentially encourage “more 

effective and affordable warnings,” resulting in increased safety for highway users and 

trains at passive grade crossings. In addition, they acknowledge that implementation of 

new grade crossing technology will not be easy and will require substantial cooperation 

between authorities and railroads to ensure success. The technical guidance in Section 

210 provides reference to 49 CFR Part 236 Subpart H, Standards for Development and 

Use of Processor-Based Signal and Train Control Systems. The authors clearly describe 

this regulation as providing a “suitable framework” for qualifying “new or novel” grade 

crossing technology. 

The specific language that may provide regulatory relief is as follows:

“If the Secretary approves by order new technology to provide warning to highway users 

at a highway-rail grade crossing and such technology is installed at a highway-rail 

grade crossing in accordance with the conditions of the approval, this determination 

preempts any State statute or regulation concerning the adequacy of the technology in 

providing warning at the crossing.” 

Of course, this is not a total panacea, and the regulatory burden is by no means 

insignificant. However, the Secretary of Transportation now has the authority to approve 

new technology. This authority supersedes any State laws, potentially resulting in a 

lower tort liability risk. Also, the use of performance-based standards for technology 

qualification relieves vendors from the burden of having to prove that the products are 

“fail-safe.” 

 

Another option may be to change the perception of non-fail-safe active warning devices

in the United States. In Australia, there is a movement to implement these systems as 

supplemental or enhancing existing signage at passive grade crossings. This would put 

them at a level equivalent to highway traffic control devices. In this manner, highway 

users of the grade crossing would still be responsible for train detection. Currently, the 

Australian Department of Transport is evaluating the potential necessity for developing 

regulatory language to introduce non-fail-safe technology, especially where passive grade 

crossings are located. This dovetails well with the requirements specified in Section 210 

of the RSIA of 2008. 
31 

Engage in Cooperative Research with TC 

Both FRA and TC are engaged in similar low-cost warning device research. A 

collaborative research effort could afford multiple opportunities to leverage costs, 

resources, and institutional knowledge. This research could result in a common North 

American low-cost warning performance criteria (see Appendix A for a sample) and 

performance guidelines for different operating environments (i.e., dark versus signalized 

territory and different levels of signaling scenarios). At a minimum, FRA should 

continue monitoring the progression of the TC research and document the lessons 

learned. The triple-axis magnet resistance train detection technology, if successfully 

tested, is potentially a “true” low-cost solution and may be a candidate for qualification 

through the 2008 RSIA. 

Human Factors Simulation Evaluation of Potential Low-Cost Technologies 

Under previous FRA research, the Volpe Center developed a driving simulator to 

evaluate driver response to different train reflector patterns. This desktop simulator 

included a personal computer for generating the vehicle dynamics and visual scenery, a 

steering wheel, pedal controls, and driving dynamics to simulate a vehicle traveling on a 

typical two-way American rural road. This simulator has subsequently been upgraded 

and could be modified to evaluate driver response to different low-cost warning device 

technologies and signage at and approaching grade crossings. This will ensure a broad 

survey of available technologies. Based on the results of this evaluation, the best 

performing technologies could be ranked and identified for possible field testing. 

 

Evaluate Potential Implications of Warning Device and Sign Changes 

The MUTCD, published by the Federal Highway Administration (FHWA), is the national 

standard for all traffic control devices installed on any street, highway, or bicycle trail 

open to public travel. The MUTCD is specifically approved by FHWA and requires that 

each State be in conformance with the standards set forth within the chapters. All 

additions, revisions, or changes to the MUTCD are developed by the National Committee 

on Uniform Traffic Control Devices (NCUTCD), a private, nonprofit organization whose 

purpose is to assist in the development of the MUTCD. NCUTCD is supported by 21 

sponsoring organizations, including AAR. 

Part 8 of the MUTCD, Traffic Controls for Highway-Rail Grade Crossings, describes 

traffic control devices, systems, and practices for grade crossings open to public travel. 

The standards are extremely specific and were developed through consensus by the 

NCUTCD membership. These include physical dimensions, graphics and colors, and 

locations of grade crossing warning signs, gates, and lights. Any modifications or 

additions to these standards resulting from low-cost warning device application will need 

to be vetted by the NCUTCD and incorporated into the MUTCD. 

 

Test Promising Technologies Identified by Previous Research 

Numerous non-track-circuit–based concepts have been documented in this report, ranging 

in maturity from conceptual to approaching commercial viability. The two most 

promising train detection technologies are based on GPS (e.g., Minnesota) and magnetic 
32 

flux (e.g., wheel sensors). Like the rest of the technologies reviewed in this report, each 

of these presents unique opportunities and challenges. For example, the Mn/DOT system 

locomotive-centric train detection system eliminates the need for installing and 

maintaining more vulnerable wayside detection systems. However, the designers were 

unable to satisfy the fail-safe operational requirement in 49 CFR Part 234.203 of the FRA 

grade crossing regulation. However, Section 210 of the 2008 RSIA presents an unusual 

chance to qualify this technology for certain rural operating environments. The wheel 

sensor technology has a fail-safe design but has yet to garner the interest from the North 

American railroad industry to reach the threshold of commercial viability. Also, the cost 

level of this technology is not well understood. 
33 

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36 

Appendix A. 

Sample Performance Criteria

Table A-1. Sample Performance Criteria from TTI Analysis of Low-Cost Warning Devices

(Roop, Roco, Olson, and Zimmer, 2005)

Category Criteria Description

Enhance 

Safety

Fail-Safe Design Yes-System detects internal component failures and activates the warning device 

No-System does not activate the warning device in all instances of component failure 

Provides 20-

Second Advanced 

Warning

Yes-System activates the warning device in compliance with the 20-second rule

No-Does not comply with “Yes” as described above 

Geometric 

Flexibility

Yes-The recommended system configuration is capable of detecting the presence of trains 

through or around obstacles (i.e., curves, trees, buildings, etc.) 

No-Does not comply with “Yes” as described above 

Reduce 

System Cost

Installation Cost 

Dollar value associated with initial construction, activation, testing, and calibration 

High-More than $8,000 

Medium-$2,000 to less than $8,000 

Low-Less than $2,000 

System Life

Projected lifespan of the proposed detection and control system (excludes the assumed 

standard warning device; i.e., pole with cross bucks and flashing lights): 

High-More than 20 years 

Medium-10 years to less than 20 years 

Low-Less than 10 years 
37 

Table A-1. Sample Performance Criteria from TTI Analysis of Low-Cost Warning Devices

(Roop, Roco, Olson, and Zimmer, 2005)

Category Criteria Description

Reliability

Failure Rate

Low-Components comply with U.S. military specifications quality 

Medium-Components comply with industrial-grade quality

High-Components are obtained from surplus sources 

Redundancy Yes-All system elements are duplicated

No-Does not comply with “Yes” as described above 

Simplicity

Simple-Uses a single electromechanical sensor, sensor and control system are contained in the 

same enclosure, sensor and control system enclosure are mounted on the warning device 

Marginal-Uses multiple electromechanical sensors, sensor and control system are contained in 

the same enclosure, sensor and control system enclosure are mounted on the warning device 

Moderate-Uses multiple electromechanical sensors, sensor and control system are enclosed 

separately and require a hardwire connection

Complex-Uses existing or comparable track circuitry. Requires direct contact with the track

Very Complex-Requires multiple sensors and activation control points that share 

communication (typically via radio)

Disruption 

Resistance

High-Control system is contained in a buried, hermetically sealed vault 

Good-Control system is locked in an aboveground steel or concrete bungalow 

Moderate-Control system is locked in an aboveground cabinet 

Poor-Control system is contained in an unlocked, aboveground cabinet 

Known/Controlled 

Failure Modes

Yes-Failure modes have been identified and are controlled 

No-Does not comply with “Yes” as described above 
38 

Table A-1. Sample Performance Criteria from TTI Analysis of Low-Cost Warning Devices

(Roop, Roco, Olson, and Zimmer, 2005)

Category Criteria Description

Installability

Ease of 

Installation

Easy-Requires installation of a single component (i.e., the warning device with mast-mounted 

detection, control, and power supply equipment) 

Moderate-Requires installation of a warning device, a separately enclosed control system, and 

a hardwire 

connection between the warning device and control system 

Hard-Requires installation of a warning device, a control system in a locked vault or 

bungalow, multiple distributed sensors with an access road, and hardwire connection between 

the warning device, control system and sensors

Site Preparation

Low-Preparation is restricted to that required for installation of the warning device

Medium-Requires construction of a simple access roadway 

High-Requires modification of the existing terrain through earthwork, removal of site 

vegetation

Maintainability

Ease of Inspection 

& Testing

Easy-Requires a simple volt-ohm-meter (VOM) to evaluate system compliance with voltage 

and resistance 

operating requirements that can be performed with minimal training

Moderate-Requires VOM and current-meter to evaluate system compliance and requires a 

moderately skilled electronic technician to test the system

Hard-Requires test equipment specifically designed for the system and a certified technician to 

test the system

Ease of Repair

Easy-Replacement of components requires simple pull-out/plug-in repair

Moderate-Replacement of components requires multiple reconnections of components 

Hard-Requires system recalibration following the replacement of each component

Compatibility Encroaches on 

Railroad Property 

No-Does not rely on components of the existing detection railroad infrastructure as elements 

of the train system

Yes-Does not comply with “No” as described above
39 

Abbreviations and Acronyms

AAR Association of American Railroads

AREMA American Railway Engineering and Maintenance-of-Way 

Association

ATV all-terrain vehicle

BNSF Burlington Northern Santa Fe

CFR Code of Federal Regulations

CWT constant warning time

FHWA Federal Highway Administration

FMEA failure modes and effects analysis

FOT field operational test

FRA Federal Railroad Administration

GPS global positioning system

IDEA Innovations Deserving Exploratory Analysis

ITS intelligent transportation system

km kilometer(s)

km/h kilometer(s) per hour

LED light-emitting diode

Mn/DOT Minnesota Department of Transportation

MOW maintenance-of-way

mph mile(s) per hour

MUTCD Manual of Uniform Traffic Control Devices

NCDOT North Carolina Department of Transportation

NCUTCD National Committee on Uniform Traffic Control Devices

NCVARR North Carolina and Virginia Railroad

PHA preliminary hazard analysis

RFTI Request for Technical Information

ROW right-of-way

RSIA Rail Safety Improvement Act

T-M traffic moment

TC Transport Canada

TC&W Twin Cities and Western Railroad

TRB Transportation Research Board

TTC Transportation Technology Center

TTCI Transportation Technology Center, Inc.

TTI Texas Transportation Institute

Volpe Center John A. Volpe National Transportation Systems Center

VOM volt-ohm-meter