Traffic Signal Preemption at Intersections Near Highway–Rail Grade Crossings (2017)

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62 Table B1 summarizes responses to the survey as well as the number of responses received. The numbers in parenthesis indicate the number of responses that reference the associated information. Note that agency comments may be summarized in multiple statements. appendix b Survey Responses TABLE B1 SUMMARY OF SURVEY RESPONSES QUESTION # OF RES P. GENERAL PRACTICE Q2 Does your agency have written policy or guidelines on the preemption of traffic signals near highway- rail grade crossings? 41 î Several U.S. agencies use the MUTCD as their policy. (7) î Two Canadian agencies use Transport Canada Standards as their policy. (2) î Other national guides used as policy proxies include: - FHWA Railroad-Highway Grade Crossing Handbook. (2) - TxDOT Guide for Determining Time Requirements for Traffic Signal Preemption at Highway-Rail Grade Crossings. (2) - ITE Preemption of Traffic Signals Near Railroad Crossings, A Recommended Practice of the Institute of Transportation Engineers. (1) î Some agencies have their own guides, which include preemption sections: - Alabama DOT Traffic Signal Design Guide and Timing Manual. (1) - Georgia DOT Design Guides. (1) - Michigan MUTCD. (1) - Montana DOT Traffic Engineering Manual. (1) - Ohio DOT Traffic Engineering Manual. (1) - Oregon DOT Traffic Signal Policy and Guidelines. (1) - Oregon DOT Traffic Signal Design Manual. (1) - Oregon DOT Railroad Preemption Design and Operation. (1) YES NO UNSURE 51% 46% 3%

63 (continued on next page) TABLE B1 (continued) QUESTION # OF RES P. Q3 Does your state have a state highway-rail grade crossing action plan? 39 î Several agencies cite not having plans because they have low crash rates. (3) î Specific action plans include: - Iowa DOT Railroad Investment Plan. (1) - Nebraska DOR Rail-Highway Crossings Program. (1) - Transport Canada guidelines. (1) î General action plans include: - Systematically reviewing crossings annually in coordination with the railway agencies. (2) - Developing a priority list of improvements each year based on accident prediction numbers. (1) QUESTION # OF RES P. PREEMPTION TIMING PRACTICE Q4 Do you only use simultaneous preemption? 40 î Two agencies only use simultaneous preemption at older installations; one agency noted that these existing locations are on an upgrade list for advanced preemption. (2) î One agency exclusively uses simultaneous preemption. They do not find that advanced preemption provides benefit because of its complexity, maintenance requirements, and reduced reliability. (1) Q5 If the answer to Question #4 is yes, what is the maximum warning time you would request? 5 Time (Seconds) î The 108-second warning time is for a high-speed rail system. For non-high- speed-rail crossings, the agency uses a minimum warning time of 66 seconds. (1) YES NO UNSURE 38% 44% 18% YES NO UNSURE 15% 77% 8% 0 8 45 52 108 0 20 40 60 80 100 120

64 QUESTION # OF RES P. Q6 If the answer to Question #4 is no, do you have a standard procedure to calculate your advance preemption time? 34 î Several agencies use the TxDOT procedure. (10) î Other procedures referenced include: - AREMA procedure. (1) - ITE TENC-99-06 procedure. (1) - LADOT procedure. (1) - Transport Canada RTD 10 procedure. (1) î Other general methods are based on the following: - Field measurements. (2) - Time to serve the critical movement at an intersection. (1) - Right-of-way transfer time plus track clearance green time. (1) Q7 Do you have a standard practice to calculate the track green clearance interval? 40 î Several agencies use the TxDOT procedure. (9) î Other procedures referenced include: - Greenshield’s formula. (1) - LADOT procedure. (1) î Other general methods are based on the following: - Field measurements. (3) - Time required for queue clearance plus a separation time; one agency noted that they use 9 seconds of separation. (2) - Minimum of 15 seconds. (1) - Time provided by the railway agency. (1) - Time to serve the critical movement at an intersection. (1) Q8 If the answer to Question #7 is yes, does it allow the routine truncation of pedestrian clearance? 32 î Several agencies prefer to serve the entire pedestrian clearance interval, but will allow truncation on a case-by-case basis. (4) î Considerations for truncating pedestrian clearance include the number of pedestrians, walking speeds, effect on countdown displays, frequency of trains, and funding available to make a change. (4) î One agency uses signs to warn pedestrians of the possibility of reduced time. (1) î One agency referenced that they reduce pedestrian clearance in accordance with MUTCD Section 4D.27. (1) YES NO UNSURE 71% 23% 6% 70% 27% 3% 75% 19% 6% TABLE B1 (continued)

65 (continued on next page) QUESTION # OF RES P. Q9 How do your signals generally operate during preempt hold intervals? 39 î Several agencies use multiple strategies, with operations depending on location (i.e., geometry, train speed, crash history, etc.). (6) î Strategies not listed in the survey include: - Flashing all-red. (3) - Flashing yellow on parallel arterial. (2) - Dwell in all-red. (1) Q10 Do you time a minimum green interval before terminating a phase that is transitioning to the track clearance interval? 40 î Several agencies determine the use of a minimum green interval based on location. (4) î Values provided by agencies include: - 7 seconds for mainline movements. (1) - 5 seconds minimum. (3) - 2-6 seconds. (1) - 1 second plus 1 second delay time. (1) - 1 second so that the default minimum green is not triggered by a value of 0. (1) Q11 Do you restrict conflicting turns across the tracks during preempt through blank- out signs or exclusive phases? 39 î Several agencies restrict conflicting turns across the track(s) through signs and exclusive phases, but the application depends on location. (7) î Specific practices being used include: - Use of exclusive phases to restrict movements across the track(s), and use of blank-out signs when more emphasis is required. (1) - Use of blank-out signs for right-turns with 200 feet or less of storage. (1) - Use of blank-out signs if exclusive phases are not present and the storage distance is less than 100 feet. (1) - Use of flashing yellow arrows for left-turns. (1) YES NO UNSURE 15% 67% 18% Dwell on Parallel Arterial Cycle through Non- Conflicting Movements Other 55% 30% 15% 87% 5% 8% TABLE B1 (continued)

66 QUESTION # OF RES P. Q12 Do you use any smart recovery strategies? 40 î Several agencies are unsure of the meaning of “smart” recovery strategies versus unsure if they have any. (3) î Agencies that use “smart” recovery strategies indicated that applications vary by location. (3) î Specific strategies being used include: - Quick recovery methods that allow reentry into coordination with other signalized intersections. (1) - Use of a single controller for several intersections to guarantee coordination. (1) - Unique selection of traffic signal exit phases and/or calls on a case-by- case basis. (1) - Simultaneous activation and deactivation of warning devices at locations where the track crosses two legs of an intersection (i.e., triangle). (1) Q13 At multiple-track locations, do you request second-train- coming logic from the railroad for the railroad warning system on new or upgraded installations? 40 î One agency receives separate preemption information from each track and direction. (1) î One agency releases preempt calls immediately after the train passes (and before the gates start to ascend). They use the clearance interval if a second train approaches. (1) Q14 Do you have train stations near crossings? 40 Q15 If the answer to Question #14 is yes, do you make special provisions for trains stopping at stations? 22 î One agency uses constant warning at all crossings, including those with train stations. (1) î One agency determines special provisions on a case-by-case basis. Considerations include the distance between the crossing and the station (and other nearby crossings). (1) Q16 If the answer to Question #15 is yes, describe the special provisions that are made for trains stopping at stations. 10 (+3) î Flash if gate-down is too long. (2) î Near-side stations do not activate crossings until requested. (2) î Gates remain down during the dwell time. (2) î Preemption time-out and preemption restart procedures. (1) î Use of a controller feature that activates the crossing as soon as motion is detected (to prevent short warning times due to accelerating trains). (1) î Limiting acceleration made by trains leaving stations. (1) î Delay timer applied by the railway agency. (1) Q17 Do you have fire preemption at rail preempt intersections? 40 î Two agencies use fire preemption on a case-by-case basis. (2) YES NO UNSURE 10% 47% 43% 20% 50% 30% 45% 42% 13% 32% 36% 32% 67% 18% 15% TABLE B1 (continued)

67 (continued on next page) QUESTION # OF RES P. Q18 Do you prioritize which preempts can override other preempts? 41 î Several agencies noted that rail preemption overrides emergency vehicle preemption. (4) î Specific preemption prioritization considerations include: - MUTCD recommendations. (1) - Track(s) crossing multiple legs of an intersection. (1) - Railway and bridge-lift preemption coordination. (1) Q19 If the answer to Question #18 is yes, describe priority for your first six preempts. Preempt 1 has the highest priority, but more than one preempt may have the same priority (first come, first serve). î Preemption uses included in the “Other” category include: - Bridge. (4) - Ramp. (3) - Queue/congestion. (3) - Aircraft taxiway. (1) 29 28 19 13 8 4 GRADE CROSSING OPERATIONS Q20 Do you use a simple, two-wire preempt? 40 î Two agencies use two-wire preempt at some but not all locations. (6)î Two agencies are no longer installing two-wire preempt, but have older crossings that use it. (3) î One agency noted that they are in the process of upgrading crossings that have two-wire preempt. (1) YES NO UNSURE 71% 12% 17% RAIL EMERGENCY TRANSIT OTHER 93% 7% 39% 57% 4% 5% 53% 21% 21% 54% 31% 15% 38% 38% 24% 75% 25% 55% 13% 32% TABLE B1 (continued)

68 QUESTION # OF RES P. Q21 If the answer to Question #20 is yes, is the circuit from the railroad normally closed (when no preempt) or normally open (when no preempt)? 31 î Two agencies use both types of circuits depending on location. (2) î One agency uses normally open circuits on mainline tracks and normally closed circuits on tracks not used as frequently, such as short spurs. (1) Q22 If the answer to Question #20 is no, describe your preempt circuitry (e.g., four- wire, serial, or other). 13 î Three-wire (with braiding/shield on each conductor, equivalent to a six- wire double-break design). (1) î Four-wire. (4) î Eight-wire. (1) î Ten-wire. (1) î 14-wire. (1) î Serial interconnect. (1) Q23 Do the majority of crossings have grade crossing predictors (“constant” warning time)? 40 î One agency uses predictors at the majority of crossings, with the exception of lower-speed crossings and locations with electrified rail. (1) î One agency uses predictors depending on the characteristics of an individual crossing. (1) î One agency noted that predictors are used at new crossings. (1) Q24 Do you preempt signals that are more than 200 feet from the crossing? 40 î Several agencies decide to apply preemption based on the queueing characteristics at an intersection. Some of these note that if queues routinely exceed 200 feet, preemption is used. (12) î Two agencies make the decision to use preemption at signals that are more than 200 feet from the crossing on a case-by-case basis. (2) î Two agencies commented that this scenario is not common. (2) î One agency indicated they have a policy to preempt signals up to 215 feet from the crossing. (1) Q25 Do any existing locations have advance preemption? 40 î Use of advance preemption ranges from nearly every crossing to only a few. (4) î Two agencies noted that all new installations have advance preemption. (2) î One agency prefers the use of simultaneous preemption. (1) YES NO UNSURE 58% 10% 32% Normally Closed Normally Open Unsure 47% 20% 33% 72% 20% 8% 67% 18% 15% TABLE B1 (continued)

69 (continued on next page) QUESTION # OF RES P. DESIGN PRACTICE Q26 Do new installations or upgrades include “constant” warning train detection? 39 î Two agencies noted that constant warning train detection depends on the railway agency. (2) î Two agencies noted that most new installations have constant warning train detection. (2) î One agency noted that the use of electrified rail may prevent the use of constant warning devices, or if train speeds are low, it may not be cost effective. (1) Q27 Do new installations have battery back-up? 40 î Use of battery back-up may depend on the following: - Location and traffic volumes. (3) - Time for an electrician to respond and history of power outage frequency and duration. (1) î One agency noted that battery back-up is installed on a case-by-case basis. (1) î One agency noted that traffic signals do not have battery back-up, but railway equipment does. (1) Q28 Do new installations have LED signal indications? 41 Q29 Would you likely use advance preemption at a new location? 40 î Several agencies decide to use advance preemption based on the characteristics of the crossing. (5) î One agency noted that they will only not use advance preemption if the track is so close to the intersection that traffic always stops on the other side of the grade crossing. (1) Q30 Do you request additional rail outputs (e.g., gate-down, island circuit, or other)? 40 î Two agencies noted that it depends on location. (2)î One agency chooses to only use simultaneous preemption for simpler maintenance and reliability. (1) î One agency noted that cost and maintenance prevents them from using additional outputs. (1) YES NO UNSURE 64% 13% 23% 75% 13% 12% 98% 2% 75% 10% 15% 38% 42% 20% TABLE B1 (continued)

70 QUESTION # OF RES P. Q31 If the answer to Question #30 is yes, which outputs? 16 (+2) î Gate-down. (9) î Gate-down and supervised. (4) î Gate-down, supervised, and health. (1) î Gate-down, supervised, health, and island. (1) î Gate-down, island, gate up. (1) î Gate-down and second gate-down. (1) Q32 Do you use vehicle gates at all new or upgraded crossings? 41 î Several agencies install vehicle gates on a case-by-case basis. (10) î Installation of vehicle gates may depend on the following: - Train volumes. (2) - Train speeds. (2) - Sight distance and vehicle AADT. (1) - Available funding. (1) - Intersection geometry. (1) î Two agencies report that installation of gates is determined by the rail way agency. (2) î One agency noted that they have found vehicle gates do not work well when the track runs through the center of the intersection. (1) Q33 Do you use pedestrian gates at gated crossings? 41 î Several agencies with pedestrian gates report that they have them installed at some locations (not all). (11) î Installation of pedestrian gates may depend on the following: - Proximity to schools. (1) - Proximity to quiet zone. (1) î Two agencies report that installation (or lack thereof) of gates is determined by the railway agency. (2) î One agency noted that they do not have any pedestrian gates but would install them if warranted. (1) YES NO UNSURE 17 2 6 2 2 Gate Down Island Supervised Health Other 54% 29% 17% 37% 46% 17% TABLE B1 (continued)

71 QUESTION # OF RES P. Q34 Do you use pre-signals? 40 î Several agencies with pre-signals report that they have them installed at a limited number of locations. (5) î Two agencies report that they have used pre-signals in the past but have not found them effective. (2) î Installation of pre-signals may depend on the following: - Crossing geometry. (1) - Installed where the storage distance is inadequate to store a design vehicle. (1) - Existence of near-side indications that can cause issues with pre-signals. (1) î One agency noted that they do not have any pre-signals but would install them if warranted. (1) Q35 Do you use queue cutters? 41 î Several agencies with queue cutters report that they have them installed at a limited number of locations. (5) î One agency reported that they have used queue cutters in the past but have not found them effective. (1) î Installation of queue cutters may depend on the following: - Crossing geometry. (1) - Used with long throats between intersection and track. (1) î One agency noted that they use a similar detection strategy to turn on signs that warn drivers not to stop on the track(s) when queues get close to the crossing. (1) î One agency noted that they do not have any queue cutters but would install them if warranted. (1) Q36 Do you use four- quadrant gates? 41 î Several agencies note that they use four-quadrant gates in limited situations. (8) î One agency noted that the railway agency prefers not to have four-quadrant gates. (1) Q37 If the answer to Question #36 is yes, when do you use four- quadrant gates? 20 (+2) î Quiet zones. (10) î Locations with safety issues. (4) î Higher-speed rail corridors. (2) î Where traffic from nearby roadways can easily go around the entrance gates. (1) î Multi-lane roadways. (1) î Main railway routes. (1) î All situations. (1) î When other measures are insufficient. (1) YES NO UNSURE 50% 40% 10% 34% 46% 20% 41% 41% 18% (continued on next page) TABLE B1 (continued)

72 QUESTION # OF RES P. Q38 Do you use any advanced train detection or railway interconnection technology? 39 Q39 If the answer to Question #38 is yes, describe the advanced train detection or railway interconnection technology. 5 î Incremental Train Control System (ITCS), which utilizes GPS and communications to provide advance activation of the crossings. (1) î DAX outputs from CWT systems. (1) î Railroad Preemption Interface System. (1) î Monitor stations at select crossings. (1) î Hardwired and radio connections. (1) MAINTENANCE PRACTICE Q40 Do you have railroad- preemption-specific training for your maintenance staff? 39 î Several agencies indicated that they do not have training because they are not a maintaining agency. Training is the responsibility of the local agencies. (5) î One agency has two levels of formal traffic signal field maintenance training plus on-the-job training. (1) î One agency has preemption information is included with signal systems training. (1) Q41 Do you have written procedures for contacting the railroad regarding activities near grade crossings? 38 î Communication conducted through planning division or agency railway- specific coordinator/engineer/office. (5) î Warning notices posted in both railway and traffic cabinets. 24-hour contact information is provided, with notice that pre-approval of changes is required. (2) î Right-of-way entry agreement is used, but may not be required if not on/near track. (1) î Agency has railway phone number for reporting track circuit issues. (1) î Transport Canada guidelines contain statement about notifying railway authority of work. (1) Q42 Do you perform routine inspections and/or maintenance of your preemption system? 39 î î One agency indicated that it does not conduct inspections because they are not a maintaining agency. One agency responded that inspections are the responsibility of the local agency. (2) î One agency pointed out that Transport Canada guidelines contain requirements for inspecting and testing preemption. (1) YES NO UNSURE 13% 49% 38% 39% 51% 10% 58% 26% 16% 61% 21% 18% TABLE B1 (continued)

73 QUESTION # OF RES P. Q43 If the answer to Question #42 is yes, how often do you perform inspections and/or maintenance? 25 (+2) î Every five years. (1) î Every three years. (2) î Every year. (18) î Bi-annually. (1) î Every three to four months. (1) î Monthly. (1) î Performed on a monthly basis as part of other maintenance. (1) î As-needed, or if malfunctions are identified. (2) î Organized by the railway agency. (2) î Performed as part of routine maintenance with varying frequency. (1) î If a major upgrade/change is made to signal or railway equipment/track. (1) Q44 Do you coordinate with the railroad’s monthly testing of preemption? 38 î Coordinate annual inspection with railway monthly inspections. (3) î Two agencies indicated that they do not coordinate testing because they are not a maintaining agency or that they do not have the authority. î One agency noted that railway staff and traffic staff test preemption on their respective systems when conducting other maintenance. (1) î When conducting inspections (with varying frequency), one agency coordinates their activity with the railway agency. (1) Q45 Do you periodically review crossings to determine the need for upgrading the rail warning system or traffic signal system? 38 î Several agencies indicated that they do not review crossings because they are not a maintaining agency. î Ongoing/as-needed reviews conducted based on findings from inspections, complaints, crashes, development reviews, etc. (2) î Upgrades are periodically made as enhancements are developed. (1) î Request feedback on operational issues from local agencies, and provide support/direction on upgrades. (1) î Based on FSP program ranking. (1) YES NO UNSURE 3 18 4 2 4 Less Frequently than Annually Annually More Frequently than Annually As-Needed Other 8% 71% 21% 37% 39% 24% (continued on next page) TABLE B1 (continued)

74 QUESTION # OF RES P. Q46 If the answer to Question #45 is yes, how often do you review crossings? 14 (+1) î Every five years. (1) î Annually. (3) î As-needed/requested (i.e., no set schedule). (9) î Depends on funding. (1) î As part of highway projects. (1) î During joint railway inspection. (1) î When the railway reports changes to rail traffic. (1) Q47 Do you shop test your cabinet and controller before installation? 38 î Vendors’ responsibility to test/factory-tested. (2) î Preemption is tested under normal circumstances and failure. (2) î One agency indicated that they do not shop test because they are not a maintaining agency. (1) î Equipment for new crossings is shop tested. Equipment for existing locations with added preemption is reviewed in the field. (1) î Controllers are shop tested but cabinets are not. (1) î Some example shop tests include the following: - Preemption during each interval. (1) - Preemption calls during manual control on. (1) - Power interruption during preemption. (1) - Power start-up during preemption. (1) YES NO UNSURE 1 3 0 9 4 Less Frequently than Annually Annually More Frequently than Annually As-Needed Other 74% 13% 13% TABLE B1 (continued)

75 QUESTION # OF RES P. Q48 Do you restrict timing changes at interconnected traffic signals to those that have been pre-approved by an appropriate staff member? 38 î Changes can only be made by trained signal timers. (2) î Two agencies require notifications from the local agencies making changes. (2) î Parameters with restrictions include the following: - Preempt parameters. (2) - Minimum green. (1) - Yellow clearance. (2) - Red clearance. (2) - Pedestrian clearance. (1) î Changes must be reviewed and approved by agency. (1) î Warning labels posted in both railway and traffic cabinets. (1) î Controllers are password protected, and additional security locks are used on cabinets. Only pre-approved controllers are allowed, which must meet safety criteria. Critical program data (affecting signal sequence or preemption) is protected by Cyclic Redundancy Check. (1) î One agency indicated that they do not have restrictions because they are not a maintaining agency. (1) Q49 Do you use contract maintenance? 38 î Several agencies use limited contract maintenance, performing most work in-house. (4) î A few agencies note that the use of contractors depends on the local agency. (3) î Two state agencies contract work to local agencies. (2) Q50 If the answer to Question #49 is yes, do you have specific procedures developed regarding coordination with the railroad? 19 î Local agencies are required to contact the state agency with changes or conflicts related to preemption. (1) î Warning notices posted in both railway and traffic cabinets. 24-hour contact information is provided, with notice that pre-approval of changes is required. (1) î Coordination efforts are dependent on the local agency. (1) î Right of Entry Agreement states to contact railway maintainer, who should be on site for inspection. (1) î Required coordination indicated on signal permit plans. (1) î Transport Canada guidelines outline procedures. (1) MONITORING ACTIVITIES YES NO UNSURE 87% 8% 5% 50% 45% 5% 37% 42% 21% (continued on next page) TABLE B1 (continued)

76 QUESTION # OF RES P. Q51 Do you record detailed rail-warning-system events beyond the preempt log in the traffic signal controller? 38 î Two agencies noted that logging is determined by the local agencies. (2) î One agency noted that there are limited locations with additional logging capabilities. (1) î Examples of detailed railway-warning-system events include: - Traffic-signal or railway-interconnect malfunctions. (1) - Remotely accessible video. (1) - Voltage monitors. (1) Q52 Do you compare design assumptions to actual operations in the field? 37 î Performed during final inspection. (1) î Verified after implementation. New installations, or existing locations undergoing considerable changes, require a joint inspection during the activation process. (1) î Queue dissipation times for track clearance green interval are compared in the field. (1) Q53 Do you have traffic signals preempted by street-running LRT? 37 î Future system planned. (1)î Existing systems include: - Northampton, Massachusetts. - Camden, New Jersey. - Charlotte, North Carolina. Q54 If the answer to Question #53 is yes, do you have written practices on the signal operation? 13 î Agency may not have written practices, but LRT agency does. (1) î Signal plans showing signal heads, preemption, and railway detection. (1) Q55 Do you have any highway-rail grade crossing research or demonstration projects underway? 37 î Intersection with recording device. (1) î Island circuit. (1) îRevising TxDOT preemption form to simplify and clarify some of the more challenging aspects. (1) YES NO UNSURE 16% 66% 18% 62% 22% 16% 27% 59% 14% 31% 46% 23% 11% 59% 30% TABLE B1 (continued)

Abbreviations and acronyms used without definitions in TRB publications: A4A Airlines for America AAAE American Association of Airport Executives AASHO American Association of State Highway Officials AASHTO American Association of State Highway and Transportation Officials ACI–NA Airports Council International–North America ACRP Airport Cooperative Research Program ADA Americans with Disabilities Act APTA American Public Transportation Association ASCE American Society of Civil Engineers ASME American Society of Mechanical Engineers ASTM American Society for Testing and Materials ATA American Trucking Associations CTAA Community Transportation Association of America CTBSSP Commercial Truck and Bus Safety Synthesis Program DHS Department of Homeland Security DOE Department of Energy EPA Environmental Protection Agency FAA Federal Aviation Administration FAST Fixing America’s Surface Transportation Act (2015) FHWA Federal Highway Administration FMCSA Federal Motor Carrier Safety Administration FRA Federal Railroad Administration FTA Federal Transit Administration HMCRP Hazardous Materials Cooperative Research Program IEEE Institute of Electrical and Electronics Engineers ISTEA Intermodal Surface Transportation Efficiency Act of 1991 ITE Institute of Transportation Engineers MAP-21 Moving Ahead for Progress in the 21st Century Act (2012) NASA National Aeronautics and Space Administration NASAO National Association of State Aviation Officials NCFRP National Cooperative Freight Research Program NCHRP National Cooperative Highway Research Program NHTSA National Highway Traffic Safety Administration NTSB National Transportation Safety Board PHMSA Pipeline and Hazardous Materials Safety Administration RITA Research and Innovative Technology Administration SAE Society of Automotive Engineers SAFETEA-LU Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (2005) TCRP Transit Cooperative Research Program TDC Transit Development Corporation TEA-21 Transportation Equity Act for the 21st Century (1998) TRB Transportation Research Board TSA Transportation Security Administration U.S.DOT United States Department of Transportation

TRANSPORTATION RESEARCH BOARD 5 0 0 F ifth S tre e t, N W W a s h in g to n , D C 2 0 0 0 1 A D D R ESS SER VICE R EQ UESTED NO N-PRO FIT O RG . U.S. PO STAG E PA ID CO LUM BIA, M D PER M IT NO . 88 Traffic Signal Preem ption at Intersections Near Highw ay–Rail Grade Crossings NCHRP Synthesis 507 TRB ISBN 978-0-309-38995-2 9 7 8 0 3 0 9 3 8 9 9 5 2 9 0 0 0 0