Modeling, evaluation and optimization of traffic incident management systems

It is now widely accepted that the congestion and congestion-related problems can be decreased by the proper use of an efficient incident management system (IMS). Since the initial investment, maintenance cost and operating cost of each response unit is considerable, there is a great need for reliable models to help evaluate and optimize the performance of such systems.; In the performance analysis area, a steady-state M/M/C queueing system under batch service interruptions is introduced to model the traffic flow on a roadway link subject to incidents. We analyze this system in steady state and present a scheme to obtain the generating function of stationary number of vehicles on a link. For those links with large C values, M/M/infinity queues under batch service interruptions can be used as an approximation. We investigate an M/M/infinity queueing system subject to random interruptions of exponentially distributed durations. It is shown that the number of customers present in the system in equilibrium is the sum of two independent random variables. One of these is the number of customers present in an ordinary M/M/infinity queue without interruptions.; For incident response and resource allocation problems in traffic incident management, we propose mathematical programming models with probabilistic constraints to address the uncertain conditions in an IMS. A mixed-integer programming (MIP) model with probabilistic constraints is proposed to address the dispatching problem with consideration given to the stochastic resource requirements at the sites of the potential incidents. For the resource allocation problem, assuming that the stochastic distribution of incidents over a network is given, we introduce a mathematical model to determine the number of service vehicles allocated to each depot to meet the requirements of the potential incidents by taking into account the stochastic nature of the resource requirement and incident occurrence probabilities.; We also develop a computer simulation software package with C ++ programming language to evaluate the performance of IMS. This simulation software can be used to simulate the occurrence of highway incidents, the dispatching of emergency vehicles, and the freeway service patrol on the network. Using this simulation software, we investigate IMS in South Jersey highway network. The investigation results could provide valuable information to the decision makers on how to improve the system performance.