Traffic Controller Logs. A traffic controller monitors detector calls and makes signal timing decisions in real-time. For approaches with advance detectors, traffic volume data can be collected and logged periodically. Table 5-3 provides an example of traffic volume data logged by a traffic controller. Table 5-3 Example of Traffic Controller Logs in the Phase One Test Date Time Name Det1 Det2 Det3 Det4 Det5 Det6 Det7 Det8 … 4/14/05 11:30 060 164th SW & Alderwood/Manor 67 35 14 11 52 50 4 24 … Depending on controller type, model, and the operating traffic management system, other event data such as changes in signal control phases and time-stamped traffic calls may be recorded. Phase change times are very valuable data for understanding signal controller decisions. However, such phase change data were not available for the Phase One test because of constraints in the traffic management system used by Snohomish County. Fortunately, some phase change information was logged by the TPRG. By analyzing the TPRG logs, we were able to understand the time associated with each priority phase change during the test period.
Traffic Controller Logs. The Phase Two test corridor was in the City of Lynnwood. The City of Lynnwood uses the Naztec traffic control system for traffic management and control. With the Naztec TMC (Traffic Management Center) software, many event data, such as the split change and time-stamped traffic calls, can be monitored. The traffic detection systems on the SR 99 corridor are Traficon’s video image processors (VIPs). Virtual loops are deployed at mid-block to detect traffic volume. The TMC server archives and reports traffic volume data periodically.
