In response to increasing concern about railroad grade crossing safety, the Federal Railroad Administration and Department of Transportation issued Safety Advisory 2010-02 recommending in part “...that railroads conduct comprehensive joint inspections of highway traffic signal pre-emption interconnection with State and local highway authorities...” 2010-02 also recommends recording devices at interconnected highway-rail grade crossings. This paper addresses a method to facilitate these goals by enabling the highway authority to independently verify that rail equipment is functioning properly, and just as importantly, enabling the railroad to independently verify that the highway traffic signal equipment is providing adequate clearance time in advance of the arrival of the train in the crossing. The method involves adding two circuits between the rail equipment and the traffic signal equipment: a crossing island circuit, and a start of the traffic clearance phase indicator from the traffic signal to the rail equipment. This system has been implemented at two intersections in Portland, Oregon, with plans for further implementation.

This research documents the operational benefits of additional phases, barrier bars, and a call-based transit priority signal-phasing strategy over a more traditional eight-phase, two-barrier preemption-based transit signal–phasing strategy. The call-based timing strategy, with a more flexible ring-and-barrier structure, takes advantage of additional phases to run less-impactful transit prioritization for light-rail trains. These two strategies have been field implemented in Portland, Oregon, at the signalized intersection of Southwest Porter Street and Southwest Moody Avenue, an intersection that has distinct signalized movements for the private-automobile, streetcar, light-rail train, bus, pedestrian, and bicycle modes. The operations of the two-intersection signal-phasing strategies were evaluated and tested by using hardware and software-in-the-loop microsimulation (in Vissim) to isolate the expected change in operational efficiency in modal delay. The two-barrier preemption-based transit signal-phasing strategy showed high variability in delay for certain movements, in particular, pedestrians. The call-based phasing strategy with flexible ring-and-barrier structure reduced total and average intersection delay. This research shows that the call-based phasing strategy with flexible ring-and-barrier structure can provide a less disruptive transit prioritization. Agencies should consider the call-phased transit priority strategy over the more traditional preemption-based strategy at a signalized intersection when ( a) delaying potential preemptive movements mode will not have large safety effects, ( b) pedestrian demand is high, ( c) preemption service will be frequent, or ( d) the intersection is operating at or over capacity.