Examining vehicle interactions during a vehicle-following manoeuvre

Heavy vehicles are significantly longer and heavier than passenger cars and consequently have quite different acceleration and braking capabilities. Heavy vehicle manoeuvres are therefore likely to influence drivers’ vehicle-following behaviour differently to cars. Heavy vehicles can also influence the behaviour of drivers of other vehicles while following a heavy vehicle. This paper used data obtained from the Interstate-80 in California to show the impacts of the presence of heavy vehicles in a traffic stream on the vehicle-following behaviour of car and heavy vehicle drivers. Four vehicle-following combinations, based on the vehicle classes of the leader and subject vehicle, are considered in this study. These combinations are car-car, car-heavy vehicle, heavy vehicle-car and heavy vehicle-heavy vehicle. The study analyses the space and time headways,, driver’s reaction time and vehicle acceleration for the four vehicle-following combinations. The results highlight the different behaviour of the vehicles in the four combinations. In summary, the presence of heavy vehicles results in a larger headways, longer reaction time and smaller variation in acceleration variation during vehicle-following behaviour. Further research is required to determine the underlying reasons for these differences.