Methods of Calculating the Traffic Flow and Travel Times in Urban Areas
Oskar Andreas Kleven, Public Road Administration Norway, Stefan Fluegel, Institute of Transport Economics, Norway
Norway is in 2014 starting up a research program to study methods of calculating the traffic flow and travel times in urban areas. The objective of this research program is to be more able to estimate effect of investments in urban areas.
Congestion has effect on transport demand and mode choice, and has significant economic effects. However, we need better methods to estimate theses effects. Focus on alternative transport helps to reduce the demand for car trips and thus the congestion. Understanding these mechanisms in urban areas is therefore essential also to analyse the effects of investment in such alternatives.
In the current strategic transport models, the models is used to calculate changes in transport demand and transport distribution (regional transport models), calculate congestion in network in a "static" manner. The travel time for a road link is calculated as a function of the volume of traffic in the individual link. However, in areas with a lot of links the congestion will evolve dynamically. The congestion on a road link at a given time will affect the congestion both on the surrounding links and in subsequent time intervals (cumulative effects). The strategic transport models will not provide a good enough description of queuing in network in such areas.
To analyse complex congestion in urban areas, we need a more "dynamic" method of estimation, similar to those found in more detailed micro models. However, in micro models only choice of route are calculated, not changes in travel demand and modal split.
We need to explore and identify how we can integrate static demand based transport models with detailed dynamic micro models, to calculate congestion, travel times and delays in a better way in urban areas. To explore and develop good methods for this is a relatively long-term R & D task. Consequently modelling of congestion in networks in urban areas is an area of research that gets increasing attention internationally.
Based on a review of international research activities and methods in this field we will present important research topics for the future. Norway is in 2014 starting up a research program to study these topics. The objective of this research program is to be more able to estimate effect of investments in urban areas.
Association for European Transport