SIMULATION OF MIXED TRAFFIC FLOW AT INTERSECTION

Abstract

Traffic simulation modelling has been known as a valuable technique for expeditious assessment of traffic flow character-istics, so that different investment decisions with regard to strategies for geometric design and pavement management of of roads can be arrived at more rationally. The earlier work on this subject was not meant for traffic conditions as obtain-ing in India because the conditions in advanced countries are different from the developing countries. A critical survey of the literature on traffic simulation modelling on a global basis indicated that no suitable model was readily available for the specific traffic and inter-section conditions obtaining in India and many other countries in developing world. The study consider signalized intersection for the study because signalized intersection in urban areas are too congest-ed for the traffic flow. For the modelling, seven different vehicles are considered, i.e. cycle, scooter, motorcycle, auto, car, bus and truck, Scooter and motor-cycle (two wheelers) are taken in one group and, truck and bus (heavy vehicles) are in another group respectively. For arriving these different types of vehicles cumulative probability distribution is considered. At intersection the traffic stream can be composed of a combination of free flowing vehicles and constrained vehicles, so for the headway between these vehicles composite exponential distribution is considered. A computer simulation model of mixed traffic flow at intersection was formulated. Delay is taken as the subtraction of arrival time from the departure time; L3ad factor,- maximum queue length, average individual delay etc. is also obtained from the simulation model. Field data were collected at an inter-section near I.S.B.T. Delhi.- The computer programme was written in FORTRAN IV and it was run at DEC 2050 system, which is available in Roorkee University. The study demonstrates that the complex problem of mixed traffic flow at the intersection can be mathematically modelled and analysed during computer simulation techniques. The results of the study may be used for improving the intersection conditions. For intersections, the methodology demonstrated in this study may be used with appropriate modifications.