MONITORING AREA CONTROL

Two methods for monitoring area traffic control are described, and the results of trials of these methods are presented. The first method, which assumes a correlation between the mean speed of a traffic stream and the recorded mean speed of buses within the stream, uses timing instruments fitted to buses to record the journey-time and stopped times. Calibration against conventional moving car observations is reported to show good correlations but emphasises the need for local calibration trials. A photogrammetric method using aerial time lapse photographs is also described. The main feature of the method lies in the method of analysis which uses a stereoscope to relate vehicle speeds to their apparent height above ground level. The theory of the method is presented, the effects of gradients discussed and the sources of possible inaccuracies are listed. The results obtained using the method are compared with the results of a licence plate survey. /TRRL/