Design of an Automated Traffic Counting System with Turning Movement Flow Analysis

摘要

The feasibility of developing an automated system for making vehicular traffic counts for at-grade intersections was investigated. Various conceptual approaches were explored; however, all calculation methods which attempted to deduce traffic-turning volumes directly from detector information were found to produce fewer than the required number of independent equations. A new technique based upon real-time forecasts of the time required for making right-turn movements is proposed. The technique utilizes the right-turn forecasting technique as a means of supplementing information collected from a system of detectors on inbound and outbound lanes, and thereby allows calculation of all traffic movements through the intersection. The accuracy of the method is improved by sensing the 'state' of the intersection signal controller. The signal-controller status permits direct calculations of all turning movements except right-turns made during green-signal indications. The proposed counting methodology was implemented through the use of off-the-shelf hardware consisting of an open-architecture microcomputer and a TTL-compatible data-acquisition board. Although the technique is independent of detector type, use of a vehicle, rather than an axle detection device, is strongly preferred.