Analysis on Road Traffic–Status Discrimination Results at Different Time Intervals

To estimate traffic status on urban road accurately and determine the appropriate traffic-status evaluation interval, this research introduces a method based on the theory of set-pair analysis, and takes the number of vehicles passing the segment continuously as time interval of evaluation. First, to improve the operating efficiency of the model, based on the summary and analysis of the current research status, time interval of evaluation could be obtained according to the number of vehide passing and the instantaneous speed is taken as a single index. Second, according to the principle of set-pair analysis, set pair H (A, B)is formed by sets A (measured data) and B (standard of indices). A traffic-status evaluation model with a five-element coefficient is established from the perspectives of identity, difference, and reverse. Finally, to verify the validity of the model, we take the measured data of the eastern segments of the South Second Ring Road in Xi'an City as an example and use the fuzzy-evaluation and set-pair analysis methods to distinguish the traffic-status grade of this segment of roads. Results prove the superiority of our method. The evaluation results of the two methods are basically the same, but the traffic-condition evaluation method based on set-pair analysis theory is more sensitive to the change in speed. When evaluating road-traffic conditions, a smaller time interval means higher sensitivity of traffic conditions to changes in speed. When the evaluation time interval is less than 1 min, the result of traffic-status evaluation is no longer affected by the time interval.