The role of advanced traveler information systems in incident management

Advanced traveler information systems (ATIS) have been proposed recently as a promising technology for improving the efficiency of urban transportation networks and reducing traffic congestion. This dissertation deals with an important application of ATIS technology: the management of incidents.; An off-peak incident is analyzed using deterministic queueing methods in an idealized corridor composed of two routes. A user equilibrium strategy is implemented to disseminate real time traffic information to vehicles equipped with ATIS. The findings show that under incident conditions, ATIS will divert all equipped vehicles to the alternate route until equilibrium is achieved. Equilibrium is maintained by reducing the rate of diversion from one route to the other through pulsed diversion of ATIS equipped vehicles. The implication is that during equilibrium some ATIS equipped vehicles will be diverted to an alternate route while others will remain on the route where the incident has occurred.; The study findings show that guided traffic is better off than unguided traffic only during the diversion period that precedes equilibrium, but this advantage is drastically reduced when a queue forms on the alternate route or where equilibrium can be achieved. System benefits increase with the fraction of guided traffic as long as it is below the critical value that causes a queue on the alternate route, but system benefits saturate when this value is exceeded. Also, system benefits do not increase with the proportion of guided traffic in cases where equilibrium can be achieved. The critical fraction does not depend on the incident parameters but does depend on two corridor parameters: the capacity of the alternate route and the corridor demand.; In conclusion, route guidance has a significant role in the management of incidents during the off-peak period, when uncongested alternate routes are likely to be available. During the peak period, however, the alternate routes are usually congested, and consequently there is a need to spread traffic over time rather than space. This can be achieved through departure time switching rather than route switching. This area is yet to be investigated and is an interesting subject for future research.