Modelling large vehicles operating speed characteristics on freeway alignment based on aggregated GPS data

Abstract

Operating speed is a basic measure for studying the safety of freeways. However, whether the designed speed matches the actual operating speed of large vehicles is worth studying. As such, this study included a large number of aggregated vehicle global positioning system (GPS) datasets used to analyse the actual speed of large vehicles under different alignment conditions on the freeway; and supplement the theoretical operating speed model. Using the traditional operating speed prediction model, the theoretical speed of each section was calculated. Two months of vehicle GPS data from freeways was extracted from a vehicle monitoring platform, the actual operating speed of each section was obtained. The similarities and differences between the theoretical operating speed and the actual vehicle speed on the horizontal and vertical curves were analysed and compared. The results indicate that the actual speed of large vehicles was obviously higher than the theoretical speed operating downhill. When the vehicle was operating uphill, the vehicle's actual speed was significantly lower than that of the theoretical speed. The actual vehicle operating speed data can be used as a new method for evaluating the safety of large vehicles on the freeway.