Much attention has traditionally been given to safety issues associated with motor-vehicle/light rail vehicle crossings. There has been somewhat less attention given, however, to issues associated with pedestrian/light rail vehicle conflicts, including collisions, near misses, evasive actions, and illegal pedestrian movements. While there are generally fewer pedestrian/light rail vehicle collisions, the results of such collisions can be more severe given the inherent vulnerability of the pedestrian. Compounding this problem, new generations of light rail vehicles are quieter than previous designs. As such, pedestrians are not as aware of oncoming light rail vehicles; this potentially increases conflicts. This is of particular importance to individuals with disabilities.

To address issues associated with pedestrian/light rail vehicle safety, light rail systems use audible signals to alert vehicles and pedestrians to oncoming trains. Audible signals and associated operating procedures, currently in use, differ from light rail system to light rail system. For example, some light rail systems require the train operator to sound a horn or bell at each grade crossing, while other systems require the train operator to sound the horn or bell only if there is an immediate hazard. Another difference in operating procedures among light rail systems involves sounding the bell on automatic warning devices at the grade crossings. Some agencies sound the bell only when the warning devices are active and the gates are lowering, but extinguish the bell once the gate has reached the horizontal position. Other agencies sound the bells at the grade crossing for the entire time that the warning devices are active, until the train has passed and the gates have fully ascended. In addition, some agencies have installed supplemental audible devices at crossings.

Complicating the use of audible signals is the fact that loud and/or frequent audible signals can create community pressure to reduce noise at crossings. In some instances, quiet zones have been established, raising concerns for vehicle and pedestrian safety at crossings.

Consequently, research was needed to develop a better understanding of the effectiveness of various audible signals and associated operating procedures, and to provide guidance to light rail systems on their potential use.

The objective of this research was to develop a guidebook on the use of audible signals and related operating procedures for pedestrian-crossing safety in a light rail transit environment. The research addressed (1) integration of these audible devices with other crossing measures (e.g., signage, channelization, warning and control devices) to maximize safety; (2) pedestrian crossings in various environments (e.g., low-speed street running, at highway-rail grade crossings in semi-exclusive rights-of-way, and at stations); (3) on-vehicle and wayside audible signals; and (4) the needs of disabled individuals.

Status:  The revised final report has been published as TCRP Research Results Digest 84 and Web-Only Document 35.