Evaluation of Traffic Delay Reduction from Automatic Workzone Information Systems Using Micro-simulation

Automated Workzone Information Systems (AWIS) have been developed, and some of them have been deployed in the field. Several field operational test studies have been conducted in the past to evaluate system functionality and reliability. However, there were few studies evaluating the effectiveness of AWIS in reducing traffic delays, which is of high interest of transportation agencies. Unlike testing AWIS system functionality, it is neither accurate nor cost-effective to evaluate the effect of AWIS on reducing traffic delay in the field study, particularly when there are diversions to other alternative routes. In this paper we propose a microscopic simulation approach to evaluate the diversion effects in tandem with delay reduction on mainline freeway. Using the traffic data collected from the field, two simulation models are calibrated corresponding to traffic conditions both before and after the AWIS is deployed. By exploiting the special topology of the simulated network (one major freeway with one alternative arterial street), in the simulation model calibration, a two-stage heuristic solution algorithm is used to estimate the origin-destination demand matrices and routing parameters simultaneously. Applying the calibrated demand matrix for the " after " scenario on both " before " and " after " simulation models, the traffic delay and other related system performance measures are obtained, therefore comparisons can be made to evaluate if AWIS has positive effect on the traffic delay reduction. The evaluation results show that AWIS deployed on the Interstate Freeway I-5 workzone in Magic Mountain area of Los Angeles can effectively reduce traffic delay on the freeway mainline and improves the overall performance of the traffic system.