Urban traffic assignment based on signalized intersection delays

Abstract

Problem. Existing methods to determine travel time on the road network links are based on the estimation of link saturation. Different formulas are used during the estimation but the ratio of traffic volume to link capacity is always the base for calculations. The main problem of such an approach is an insufficient justification of the lane capacity value which defines link capacity. It causes doubts about the background of the approach application regarding urban traffic flows. At the same time, authoritative traffic management guidelines declare that when there are signal-controlled intersections on the link then the link capacity is restricted by the intersection with minimal capacity. Thus, the alternative to the known traffic assignment approach based on link capacity can be created and then used to make the assignment on the base of delays at intersections. Evaluation of such an alternative is the actual task as the new approach to traffic assignment opens the scope for improving the accuracy of modelling the traffic flows in cities. Goal. The new approach to traffic assignment on the base of intersection delays needs to be tested for the usefulness for transport modelling practice. Methodology. The alternative approaches to traffic assignment were experimentally compared based on the parameters of the transport model, which provide the compliance of the calculated average vehicles’ speed with the factual one. Results. The new approach to traffic assignment based on intersection delays allows a more accurate calcu-lation of traffic volumes. Originality. The new ap-proach to traffic assignment based on intersection delays allows avoiding the need to set restrictions on road network links’ capacity. Practical value. Re-ceived results clarify the way to set the free-flow travel time of network objects in VISUM and allow increasing accuracy of urban traffic flows modelling.

Keywords

• traffic flow
• vehicle speed
• traffic volume
• controlled intersection
• vd function
• transport model
• visum