Original Article | 2013, Vol.35, No.4, pp. 489-499
Maximum flow in road networks with speed-dependent capacities – application to Bangkok traffic
Elvin J Moore, Wisut Kichainukon and Utomporn Phalavonk
pp. 489 - 499
Abstract
A road network can be modeled as a graph with a set of nodes representing intersections and a set of weighted edges representing road segments between intersections. In this paper, a traffic flow problem is studied, where edge weights represent road capacities (maximum vehicles per hour) that are functions of the traffic speed (km/hr) and traffic density (vehicles per kilometer). To estimate road capacities for a given speed, empirical data on safe vehicle separations for a given speed are used. A modified version of the Ford-Fulkerson algorithm is developed to solve maximum flow problems with speeddependent capacities, with both one-way and two-way flows allowed on edges and with multiple source and target nodes. The modified algorithm is used to estimate maximum traffic flow through a selected network of roads in Bangkok. It was found that the maximum safe traffic flow occurs at a speed of 30 km/hr.
