Plum, Roger

This study was conducted to develop a rational method for selecting the most appropriate type of traffic control at construction sites involving the closing of a one-lane bridge. The study consisted of a literature review, a survey of practices in other states, the observation of a number of actual construction sites, the collection and analysis of data from these construction sites and finally, the development of methods for estimating the capacity and measuring the effectiveness of various types of traffic control. As a result, a method for selecting an appropriate type of traffic was developed. This method takes into account variables such as sight distance, bridge length, traffic volumes and capacity, consideration of the costs and benefits of various types of control and an analysis of the geometric features of the geometric features of the approaches to the bridge.

A microscopic, stochastic model for intersection design and traffic flow analysis is presented in this report. A simulation program, INTERSIM, based on this modeling, is developed. The INTERSIM program can be used to evaluate alternative control schemes and geometric configurations. INTERIM can also assist in solving traffic operation and management problems, e.g., determining optimum signal phasing and timing of intersections via an iterative process. The most common situations encountered in practice are examined. These include: four-way and T-intersections with up to three lanes on each approach; stop sign control; signal control (fixed time or vehicle actuated) with various phasing schemes; detector placement and functions, multi-use lanes; protected and permissive left-turn movements; and right turns on red, among others. The proposed modeling applies to both over-saturated and under-saturated traffic conditions. INTERSIM is superior to the other intersection simulation programs due to its ease of operation and fast execution speed.