CITY LOGISTICS: FREIGHT DISTRIBUTION MANAGEMENT WITH TIME-DEPENDENT TRAVEL TIMES AND DISRUPTIVE EVENTS

摘要

This paper addresses freight management in large, congested urban settings. Congestioncreates a substantial variation in travel time (speeds) during morning peak and evening peakperiods. Besides the day to day dynamics of traffic conditions, traffic incidents also contributesignificantly to urban congestion resulting in unplanned travel delays. Urban route designs thatignore these significant variations are often found to be inefficient or even infeasible (in terms ofdelivery or pick-up time windows) within a congested traffic environment. This limitation maylead to delays, higher operational costs, and inferior customer service. To take account of thedynamics of traffic conditions, the proposed modeling framework includes an underlyingdynamic network traffic simulation-assignment (DTA) model which is able to compute time  dependentshortest paths (TDSP) and simulate individual vehicles on a realistic representation ofthe urban road network elements, including signalization, ramp metering, and other operationalcontrols. A two-phase set-partitioning based heuristic approach is proposed to construct freightvehicle routes. No parameter tuning is required. The integrated modeling framework is firsttested on a small network and then the application is demonstrated on a real world urban network,the Chicago area network, with problem instances of up to 500 customers with TDSP updated at10-minute intervals.