Investigation of the Impact of Different Rainfall Intensities on Macroscopic Traffic Variables of Urban Road Networks

For all road users and managers, rainfall events are seen as a source of uncertainty that can affect both traffic safety and traffic operation. The investigation of the impact of different rainfall intensities on traffic operations of urban road network represents the first step toward the development of weather-responsive traffic management strategies. An empirical analysis is carried out on a major arterial network located on Haizhu district of Guangzhou, China. The results indicate that different rainfall intensities have divergent impacts on macroscopic traffic variables. Specifically, the precipitation resulted in a significant decrease in weighted free-flow speed and weighted jam density of the study network. Moreover, heavy rain, rainstorm, and heavy rainstorm have remarkably negative effects on macroscopic traffic parameters, which produced critical accumulation and maximum production reduction of 10.5%, 22.2%, 15.1% and 16.6%, 21.6%, 15.6%, respectively. While light rain and moderate rain have relatively small affect on network.