A new approach to diagnose urban delivery areas plans

In this paper we develop a tool (DALSIM - delivery areas and logistics simulation), following the hybrid model described in our previous work that uses the operations research and systems dynamics. The tool is composed of two modules: a module for the simulation of delivery areas at local level based on queuing systems, and the second one simulates the spread of the obstruction on the overall flow of traffic during the deliveries based on systems dynamics. The first module considers each delivery area as a queue with a capacity, a radius of neighborhood (the maximum distance between the place to deliver and the delivery area), an arrival rate of goods vehicles and a departure rate. Then, three types of vehicles are considered to build the second module among their status on the network: the obstructing vehicles, the obstructed vehicles and the others vehicles (which are neither obstructing nor obstructed). The obstructing vehicles are the goods vehicles which do not find any legal place to deliver the goods, i.e when all the delivery areas are full or which deliberately do not use facilities. The obstructed vehicles are the vehicles affected by the impacts of the obstructing vehicles, which is traduced by the decrease of efficiency. The tool allows the study of the relationship between the obstructing vehicles and the obstructed vehicles and puts forward the spread of the obstruction. Our work shows that the traffic flows are directly influenced by the delivery areas scheme and the tool allows a representation of the reality and is validated in La Rochelle.