Impact of bicycle traffic on the Macroscopic Fundamental Diagram: Some empirical findings in Shanghai

Abstract

Interactions between bicycles and cars have attracted increasing attention during the recent years. This paper aims to investigate the impact of bicycle traffic on the macroscopic fundamental diagrams (MFDs) for urban car traffic. Based on the empirical data, we develop a Bicycle Congestion Index (BCI)-based functional form of MFD relating network bicycle flow and car flow reductions. A link-based method is also proposed to estimate the MFD, considering the spilling behaviors of bicycles at the link level. The results indicate that the effect of bicycle traffic on car MFD varies with different traffic conditions and network features. Compared with car-only roads, it is more efficient to increase network car flow by installing physically separated facilities and reducing the number of spilling bicycles. To this end, various traffic management strategies may be applied in the city of Shanghai, such as lifting the ban of cyclists on the central city area, building physically connected facilities to existing segments, and enforcing stricter operational regulations and management on bicycle traffic.