Advances on stochastic traffic assignment model for driver information system applications

Most metropolitan areas around the world face a variety of problems, including serious traffic congestion and high accident rates during peak hours. Upgrading the existing expressway networks by the application of electronic information and communication technology is one way to curtail these problems. Recently, increased attention has been paid to the provision of the driver information system (DIS) such as the estimated journey times on major routes for drivers. The DIS should help drivers to select better routes and guide them to utilise existing expressway networks efficiently. This can be regarded as one possible strategy for effective traffic management.; For a traffic surveillance and information system using the DIS, the number of speed detectors (or probe vehicles) required is very important because it affects the precision of the measurement of the vehicular travel times. In this study, a bilevel programming model is proposed to determine the number of speed detectors in a network with travel time information provided by the DIS. The lower-level problem is a stochastic probit assignment model to take account of the effects of various measurement on and perceived errors in travel times. The upper-level problem is to determine the optimal speed detector density that minimizes the measured link travel time errors, as well as the social cost of the speed detectors. Numerical examples are used to illustrate the application of the proposed model and a solution algorithm for determining the optimal speed detector density.; Apart from the cost of the DIS (in terms of the social cost of the speed detectors), it is also important to examine the benefits of the DIS for evaluation purposes. In this study, a time-dependent stochastic probit assignment model is proposed for assessing the benefits of providing the DIS, The simulation technique, the shortest path algorithm and the method of successive average (MSA) are adopted for solving the proposed stochastic probit assignment model. By applying the proposed model and solution algorithm to an example network with and without the DIS, the total network travel times can be computed and compared.; The previous related research work on assessing the DIS show that the accuracy of the provided travel time information affects the benefits arising from the DIS provision. Therefore, a new method is proposed to estimate link travel times based on speed detector data in comparison with the other two existing methods.; Although the above various models have been proposed for assessing the effects of the DIS, it is still necessary to validate the drivers' responses to the DIS in practice. (Abstract shortened by UMI.)...