Real-time route diversion control at congested off-ramp areas : part II : route guidance versus off-ramp closure

Abstract

This paper investigates the application of real-time route diversion policies, with or without off-ramp closure, to address recurrent motorway traffic congestion created due to a saturated off-ramp. In particular, the proposed route diversion policies attempt to avoid the off-ramp queue spill-over onto the motorway mainstream and the resulting motorway congestion by re- routing the motorway vehicles through nearby off-ramps towards the same destination. This paper addresses the case where real-time route guidance strategies, based on user-optimum considerations, are not sufficient to resolve the spill-over and motorway congestion problem, which may call for harsh measures (off-ramp closure) to force route diversion; while other cases are treated in a companion paper. The proposed route diversion concepts are tested for a hypothetical, but quite typical network infrastructure and traffic scenario by use of macroscopic simulation. The obtained simulation results are compared to the case where no route diversion is employed, and reveal interesting features and the potential for significant improvements.