Urbasimce: A dynamic model for assignment and cold start emission

In an urban setting, the cold engine pollutant emission of vehicles constitutes a important fraction of total pollutant emission. Cold start emission is difficult to estimate, as it depends on the local fraction of vehicles running on cold engines. In principle knowledge of this fraction requires the knowledge of travelers’ activity plans. The paper proposes a different approach: to use parking data, and parking dynamics, in order to estimate the volume of traffic running on cold engine which is generated in any link at any time. A macroscopic traffic flow model, derived from the GSOM family (generic second order modeling), is used to propagate the flow of vehicles running on cold engines. The model is dynamic, it is compatible with cross-entropy dynamic assignment, and can thus be used with various levels of data availability. The main innovations of the paper are: the GSOM model with cold emission travel time as an attribute, the parking in/outflow model, and the use of parking dynamics for the estimation of cold start emission.