Playback

Data Acquisition and Playback System for Traffic Signals

This project met its objectives which were to develop a system to simulate actual traffic conditions in a controlled shop test of traffic signal installations and a system to evaluate coordinated traffic signal performance based on the actual flow of traffic through the intersections. The first system uses data from the traffic signal monitor/recorder which was developed under an earlier contract. A custom designed interface allows an IBM PC or compatible computer to drive a shop test with actual field data. This capability is especially useful for correcting difficult to diagnose signal failures. The other system consists of five data acquisition devices which collect synchronized time stamped vehicle actuations and green times from traffic signal installations and the software to display this information as a series of time-space diagrams. Data are plotted in the form of a standard time-space diagram with vehicle actuations shown along the bar of signal colors for each intersection. This type of display highlights the progress of traffic relative to the traffic signal cycle.

Design of a Capture/playback Routine for the DARE Card that Stores Samples Into a SCSI Drive in Real Time

Implementation of Coordinated Signal Monitoring and Playback System

The emphasis of this project was the implementation of the coordinated signal monitoring and playback system which was developed in an earlier project. The purpose of that system is to evaluate the performance of a system of coordinated signals. The user collects data on vehicle actuations and signal states for a series of coordinated signals and the system synchronizes the observations in time and displays the equivalent of a time-space diagram based on actual rather than theoretical traffic flow. Another objective was to develop a portable battery operated vehicle detection unit that would communicate with the data acquisition unit over an RF link.