Background / Overview

Wisconsin Traffic Engineering Council Issue Paper 10 – Traffic Signals near Railroad Crossing

Background / Overview If the pedestrian change interval is interrupted or shortened as a part Approximately every two hours, either a vehicle or a pedestrian is of a transition into a preemption sequence, the countdown pedestrian struck by a train in the United States. In 2007, incidents at public signal display should be discontinued and go dark immediately upon highway-rail crossings in the United States resulted in 299 deaths and activation of the preemption transition. 817 injuries. Where a signalized highway intersection exists in close proximity to a railroad crossing, the railroad and traffic signal control Preemption Time equipment should be interconnected, and the normal operation of the Total warning time is maximum of Traffic Signal Maximum Preemption traffic signals controlling the intersection should be preempted to Time (TSMPT) and railroad warning time. TSMPT includes adjustment operate in a special control mode when trains are approaching. The time, traffic signal equipment delay, min. pedestrian walk and objective of a successful preempt is to take control of the intersection clearance or min. green for conflicting phase, yellow change Interval, traffic signal displays and provide for the passage of a train, no matter red clearance interval, dissipation of queued vehicles or queue where in the normal traffic signal operation the preempt occurs. clearance, yellow change and red clearance intervals, and separation time. Current National Practices Roundabouts Near Railroad Crossings The Manual on Uniform Traffic Control Devices recommends the use Where roundabouts, traffic circles, or circular intersections include or of traffic signal preemption, whenever the distance between the grade are within close proximity to a highway-rail grade crossing, an crossing and signalized intersection is 200 feet or less. Research has engineering study shall be made to determine if queuing could impact suggested that this distance criterion is inadequate, and that the highway-rail grade crossing. If traffic queues impact the highway- preemption sometimes may be appropriate when the distance is rail grade crossing, provisions shall be made to clear highway traffic much larger than 200 feet. The Institute of Transportation Engineer’s from the highway-rail grade crossing prior to the arrival of a train. (ITE) Recommended Practice on the Preemption of Traffic Signals Near Some options suggested in the proposed MUTCD are elimination of Railroad Grade Crossings highlights the need for preemption to be the roundabout, geometric design revisions, highway-rail grade based on a detailed queuing analysis and provides a procedure for crossing warning devices, highway traffic signals, traffic metering computing 95th percentile queue lengths. devices and activated signs.

Preemption Sequence Proposed 2009 MUTCD requires that signals with railroad preemption All controller units provide the same basic preemption sequencing: should have backup power, 10 years from the effective date of the Entry into preemption, Termination of the interval in operation, Clear Final Rule for 2009 MUTCD. track intervals, Preemption hold intervals and Return to normal operations. Current Wisconsin Practices Guidance provided in WisDOT Traffic Guidelines Manual 4-2-34. Refers MUTCD requires that during the transition into preemption control: to MUTCD Section 4D.13 and 8D.07. Signal controllers should be The yellow change interval, and any red clearance interval that programmed to operate a sub-routine in case crossing goes into fail- follows, shall not be shortened or omitted. The shortening or omission safe mode. of any pedestrian walk interval and/or pedestrian change interval shall be permitted. The return to the previous steady green signal Technical Issues indication shall be permitted following a steady yellow signal . RR Preemption Operational Issues indication in the same signal face, omitting the red clearance interval, o Train Detection Circuitry: Fixed, Motion Sensor, Constant if any. Warning Time o Advance/Simultaneous Preemption During preemption control and during the transition out of preemption o Termination of Pedestrian intervals control: o Track Clearance Intervals The shortening or omission of any yellow change interval, and of any o Successive Preemptions red clearance interval that follows, shall not be permitted. A signal o Phase Plan for RR Preemption: Split Phasing, indication sequence from a steady yellow signal indication to a steady Simultaneous Intersection Clearance, Concurrent green signal indication shall not be permitted. Intersection Clearance . Institutional/Communication issues with multiple stakeholders

Wisconsin Traffic Operations and Safety (TOPS) Laboratory www.topslab.wisc.edu Institute of Transportation Engineers-Wisconsin Section www.itewisconsin.org . Backup Power . Signing

Additional Resources . NCHRP Synthesis: Traffic Signal Operations Near Highway-rail Grade Crossings. Available online at http://onlinepubs.trb.org/Onlinepubs/nchrp/nchrp_syn_271.pdf . Guide for Traffic Signal Preemption Near Railroad Grade Crossing. Available online at http://tti.tamu.edu/documents/1439-9.pdf . Preemption of Traffic Signals Near Railroad Crossings: An ITE Recommended Practice. Prepared by Traffic Engineering Council Committee TENC-99-06. Washington, DC: Institute of Transportation Engineers, 2006. . Manual on Uniform Traffic Control Devices. Available online at http://mutcd.fhwa.dot.gov/pdfs/2003r1r2/mutcd2003r1r2complet. pdf . 2007 Notice of Proposed Amendments for the MUTCD. http://mutcd.fhwa.dot.gov/resources/proposed_amend/npa_textsh owingrev.pdf . Railroad Preemption Overview. Available online at http://www.signalsystems.org.vt.edu/documents/July2003AnnualM

eeting/3-66/NCHRP3-66%20rr%20preemption%20background %20final.pdf . WisDOT Traffic Guidelines Manual 4-2-34

Wisconsin Traffic Operations and Safety (TOPS) Laboratory www.topslab.wisc.edu Institute of Transportation Engineers-Wisconsin Section www.itewisconsin.org