Lessons Learned From New York City’s Wireless Traffic Control System Deployment

摘要

Most of traffic control systems today use some form of wired infrastructure, typically fiber,copper, leased services, or point-to-point microwave. As technology has progressed, thesesystems have evolved from basic slow speed analog systems to gigabit fiber using networkcommunications. However, a wired infrastructure requires a stable conduit system, and this isnot available in older urban environments, such as New York City (NYC). As a result, NYChas undertaken the deployment of a large scale wireless infrastructure to service its inventoryof over 12,000 traffic controllers. As of this summer, over 7,500 intersections had beenconnected to this wireless network; they have an aggressive procurement and installationprogram underway such that this number will exceed 12,000 by the fall of 2013. NYC isusing this network to support vehicle probe data collection, vehicle detection, traffic control,and several other emergency services. Early testing revealed that second-by-second pollingwas not practical in the RF environment, therefore the communications paradigm wasmodified to use exception based reporting (EBR) and extensions to the NTCIP standards tosupport one second data fidelity using minimal bandwidth. By selecting the appropriateschemes using EBR, the system is able to provide acceptable communications in spite of thetypical wireless communications problems and automate the system failure recovery andreporting system. This paper presents the NYC implementation and lessons learned.