关键词: 交通运输工程, 通行能力, 交通流, 混合放行, 交通冲突

Abstract: A calculation method for traffic capacity at intersections is a basic condition of urban congestion control. In view of the mixed release of traffic flow at urban road intersections, first of all, combined with the characteristics of traffic flow in all directions, it was clear that the traffic flow had the basic attributes of mixed release between signal control and nonsignal control. Secondly, the law of the conflict of traffic entities was applied and the concept of the complex coefficient of traffic conflicts and its traffic capacity reduction method were proposed under the mixed release of traffic flow. And the traditional traffic capacity theory was analyzed by analogy to obtain the traffic capacity calculation method of straight and rightturning directions. Thirdly, referring to the theory of crossing gap, the compensation benefit of left turn vehicles was introduced, and the capacity calculation method of left turn direction was obtained. Furtherly, a basic traffic capacity calculation model for common lane layouts was established. Finally, VISSIM was applied to obtain data and calibrate the reduction coefficient, so as to build a comprehensive calculation model for the capacity of the mixed release of traffic flow at intersections. The verification indicates that the calculated traffic capacity of the proposed model is basically consistent with the actual traffic capacity, with an average error of 4.9%, which better reflects the actual situation of the mixed release of traffic flow at intersections in China.

Key words: traffic and transportation engineering, traffic capacity, traffic flow, mixed release, traffic conflict