Preemption Versus Priority Service for Light Rail Transit Vehicles

摘要

Naztec, Inc. developed light rail preemption software for the $1,26 billion Hudson-Bergen Light Rail Project for New Jersey Transit in 1998 as a sub-contractor to Raytheon Engineers & Contractors, Inc. This system preempts approximately 100 traffic signals located on the rail between Newark, New Jersey, and Manhattan and provides status information to the NJ Transit control center. This system has been in operation for over 4 years; when the Hudson-Bergen Project is completed in 2005, the rail system is expected to carry in excess of 66,000 passengers per day, The Hudson-Bergen light rail software supports a dual-track system with separate advance call, check-in, and check-out detectors installed in the track. These detectors insure that the light rail vehicle is serviced without stopping and that the track is clear before returning to normal operation. The controller software allows overlapping light rail operation on the dual track system and provides several features that improve the stability of the system. Naztec, Inc. is currently developing transit priority software based on NTCIP 1211 that can be applied to light rail as well as transit operations. The issue of preemption versus priority service involves competing demands between roadway users and transit. The object definitions from NTCIP 1211 can be applied to "compromise" both approaches. An overview of Naztec's experience developing traffic signal controller software for light rail preemption and priority service is provided. It is also explained how NTCIP 1211 can provide a common framework for preemption and priority based service to strike a balance between transit and system needs. Light rail preemption developed for the Hudson-Bergen Project in light of the emerging national standard, NTCIP 1211 Object Definitions for Signal Control and Prioritization" ― is discussed (1). Currently, there is a lack of uniformity in how preemption and priority service is applied to light rail operations around the country. Hopefully, the features and operation described here for the Hudson-Bergen Project will provide insight for those charged with developing standards for light rail operation.