20: A traffic Flow Model for Urban Traffic Analysis: Extensions of the LWR Model for Urban and Environmental Applications

The aim of this paper is to propose extensions to the LWR model in order to improve its capacity to fit with urban and environmental applications. Inclusion of public transport vehicles and vehicles kinematics during transitional stages (acceleration and deceleration) are studied in a continuous way using moving boundary conditions concept. The problems raised by the numerical resolution are then analysed. Eventually, urban and environmental applications of such an extended model are presented as well as first results.

Urban use of traffic models includes several types of applications, each of which requires specific types of model. Traditional planning applications essentially involve models such as EMME/2 (EMME/2, 1998) or others, which are mainly static and devoted to the description of traffic assignment on wide networks. Optimisation of traffic signal settings have used for years simulation tools like TRANSYT (Robertson, 1969) and many others, also based on a very raw description of traffic flow. Operational planning of local projects (intersection or network design, traffic operation strategies...) sometimes uses microscopic models such as VISSIM (Fellendorf, 1994) or PARAMICS (Cameron and Duncan, 1996).