Research objectives were to explore possibilities of more accurate and efficient methods of field measurements at intersections and to study new techniques that would assist in determining whether the best use is being made of traffic control devices. Two data collecting methods were developed utilizing time-lapse cameras suspended over the center of intersections. One method involved a remote-controlled 16-mm bolex camera installed on a rotating platform. The second method, based on a 70-mm maurer p.2 camera, used four mirrors to bring all four approaches into the field of vision. Simultaneous traffic data could thus be obtained on all approaches. A digital simulation model was developed and programmed for the ibm 7094 computer. The technique, involving the combined use of the split-image camera and a simulation model of signalized intersections, was tested on a limited scale. The model has been validated by data obtained at a signalized intersection. The effect of changes in the timing of the semiactuated signal has been simulated. The model can also be used to simulate pretimed and fully actuated traffic signals. The three different signal types were compared. Under the traffic conditions investigated, the semiactuated signal was found to be the least efficient. The pretimed signal resulted in reduced stopped-time delay rates, but the most efficient operation was provided by the fully actuated signal. (Author/publisher)
Samenvatting