The Impact of Weather on Traffic Speed in Urban Area

Abstract

The issue of the impact of weather conditions on trip speed of vehicles has been studied for a long time and it is still the subject of many scientific researches. The impact of atmospheric conditions on the speed with which drivers drive their vehicles seems to be obvious. Good weather conditions, sunny weather with good visibility surely provokes higher speed while rainfall, wind and visibility limitations will force drivers to reduce speed, drive with more concentration, and be more cautious. In the light of emerging new possibilities of acquiring data on vehicle speed, especially travel speed indicating the speed of trip between designated speed measurement points using modern measurement technology new researches are possible. Increasingly in the ITS systems being implemented mainly in urban areas, ANPR (Automatic Number Plate Recognition) cameras are one of the ITS element. These cameras make it possible to determine the real time of appearance of the vehicle in the register area of the camera, thus determining both the matrix of trips between each two observation points (ANPR cameras), but also the vehicle’s ride time between successive cameras, and thus the speed of trip. In conjunction with data on weather conditions registered by several dedicated weather stations, they allow to significantly increase the research sample in terms of vehicle speed, and thus to obtain a statistically more confident inference. Thus, it gives a chance for further analysis regarding the impact of atmospheric conditions on road traffic conditions, including on travel speed and capacity of transport infrastructure. The article will present the results of empirical analyses to determine the impact of weather conditions (including temperature, ice thickness, air pressure and precipitation) on the vehicle trip speed.