Urban Road Traffic Impedance Function—Dalian City Case Study

Abstract

The typical U.S. Bureau of Public Roads (BPR) volume-delay function is modified to construct the more suitable model to China’s road traffic situation. Factors influencing road traffic impedance, such as the number of lanes, speed limit, intersection density, bus stop density, saturation and congestion are considered. On the basis of actual data collected from different main roads in Dalian city, traffic impedance functions for different road types (expressway, trunk road, secondary trunk road and slip road) are calculated using SPSS software. The results analysis of the traditional and improved BPR volume-delay functions is compared to certify the useful improved BPR volume-delay function. To apply road traffic impedance to the traditional four-step model, we calculate the daily conversion coefficients. These reflect the relationship between hourly traffic impedance and daily impedance function and suggest the suitable usage of daily conversion coefficients in further research.