Whether it is a state of the art computerized traffic management system with fiber optic communications or a simple time based coordinated system, the most important component of a well running signal system are the timings programmed into the controller. The signal timings are typically developed with one of the many signal timing software packages, the results are then implemented in the field as an initial starting point. The final and often neglected step is the fine tuning or field adjustments made to the split timings and intersection offsets. These adjustments are made from observing the timings in actual traffic conditions by driving the system and observing individual intersection operation. This is a very critical step of the timing process that can be very time consuming and can span over several days depending on the number of signals in the system, the duration of the targeted traffic pattern, and how many new individual timing patterns are implemented within the system. The use of time-space diagram generator software that integrates the data produced by a low cost G.P.S. receiver can greatly reduce the time and effort needed to properly fine tune a coordinated signal system. This paper will focus on the advantages of using this software/G.P.S. combination and how it can be used to verify network layout and signal system operation, display and plot in real-time the trajectory of the study vehicle through the system on the time space diagram, and the development of travel time and delay studies.
Abstract