Coupled Microscopic Modelling of Traffic Demand and Traffic Flow on a City Level

Coupled Microscopic Modelling of Traffic Demand and Traffic Flow on a City Level


Daniel Krajzewicz, German Aerospace Center, Jakob Erdmann, German Aerospace Center, Matthias Heinrichs, German Aerospace Center


The paper will present a microscopic simulation model built by coupling a microscopic demand and a microscopic traffic flow model. The benefits of using a microscopic approach will be pointed out. Finally, some use cases will be presented.


Microscopic models of traffic demand and traffic flow have reached a maturity that allows applying them for investigating large-scale effects of measures and/or developments. In microscopic models, every participant is described individually by a set of attributes. Demand models use individual persons’ and household attributes such as sex, age, employment status, home location, and the availability of mobility options for computing the person’s mobility in a region defined by activity locations and mode-dependent travel times. Traffic flow models replicate the movement of individual users – may they be vehicles or individual persons as well – through a given transportation network. As in demand models, every participant is defined using a set of attributes, mainly ones that describe its physical attributes, such as the maximum acceleration and deceleration capabilities, the maximum speed or the emission class.
The microscopic representation of user and vehicle groups is intrinsically sensitive to a large number of influences, because they directly change the availability of resources that determine the mode and location choice. The usage of disaggregated populations and vehicle fleets additionally enables to investigate the effects of measures that influence a part of the population or the vehicle fleet, such as environmental zones or parking fees.
The paper outlines the fundamentals of microscopic models and explains why it is necessary to take into account the inter-dependencies between the demand and the traffic flow. Then, a realization of such a combination of two microscopic tools is presented. The used tools for computing the demand and the traffic flow are respectively TAPAS and SUMO, both developed at the German Aerospace Center. The paper will additionally describe this combination’s capability to simulate vehicular emissions realized via the built-in instantaneous emission model PHEMlight.
Different use cases are presented afterwards, focusing on the benefits of microscopic approaches compared to traditional macroscopic planning approaches. The presented use cases will cover topics such as the introduction of speed limits, environmental zones, and new transport modes. The paper will close with a summary on further research topics.


Association for European Transport