01559846

Component

In this paper, a method of real time traffic signal instrumentation is introduced and described. Current practices of cabinet instrumentation methods require physical electrical connections to each traffic signal being instrumented. These methods are labor intensive to install and require a certified technician in certain states due to the 120VAC signals used. The new method obtains information concerning the traffic signal status derived from existing equipment within National Electrical Manufacturers Association (NEMA) TS2 traffic cabinets by monitoring the Synchronous Data Link Control (SDLC) network. Using the SDLC interface reduces the risk associated with high voltage allowing for a more time efficient installation. The SDLC, being critical to this approach to instrumentation, is described in detail as to allow the reader to understand the mechanism to retrieve the desired information. A case study demonstrates the proposed SDLC-based instrumentation method with an Advanced Accessible Pedestrian Systems (AAPS). Comparisons between the proposed SDLC method and current methods of traffic signal instrumentation showed that the decoding time of sensing a traffic signal state in the new method is more consistent with devices already in the traffic cabinet. It is demonstrated that using a single large scale integrated circuit based design has higher component reliability than a design with multiple small scale integration devices. This new method can be used in other traffic signal system applications such as an SDLC Interface Device or a device to log the state of different input/output channels at the signalized intersection.

This paper was sponsored by TRB committee AHB25 Traffic Signal Systems.

01550057

15-3047

English

20p

2015

Transportation Research Board 94th Annual Meeting

Digital/other

Figures; References

Case studies; Instrumentation; Integrated circuits; Methodology; Traffic signals

Data Link; National Electrical Manufacturers Association

Data and Information Technology; Design; Highways; Operations and Traffic Management; I20: Design and Planning of Transport Infrastructure; I72: Traffic and Transport Planning; I73: Traffic Control

Transportation Research Board Annual Meeting 2015 Paper #15-3047

TRIS, TRB, ATRI

Dec 30 2014 1:01PM