Effect of Rainfall on Traffic Flow Characteristics During Night Time

Abstract

Understanding traffic behavior for obtaining a smooth, safe and economical traffic operation requires a thorough knowledge of traffic flow parameters and their mutual relationships.Eventhough adverse weather can reduce traffic efficiencies, there are still questions to answer regarding the relationship between weather conditions and traffic flow at night. This paper presents an investigation of the rainfall effects to the traffic flow characteristics on atwo-lane rural highway during night time. The traffic data and corresponding rainfall data for uninterrupted road segment of Federal route 3 at Dungun, Terengganu were collected under road lighting condition during the north-east monsoon season. The effect of good weather condition, light rain, moderate rain and heavy rain conditions on speed, flow and density were quantified and compared. Results from the analysis indicate that mean speed, mean flow and mean density are reduced under various rainfall conditions. In general, the impact of good weather and various rainfall conditions on Greenshield’s fundamental traffic flow relationship have weak correlations except for the relationship between flow and density. The important points in the fundamental diagram derived from flow-density relationships indicated that critical density, maximum flow, critical speed, jam density and free flow speed of roadway all decrease as rainfall intensity increases. It can be concluded that traffic flow characteristics of two-lane rural highway in Terengganu are affected by rainfall conditions.

Synergistic Influence of Rainstorm and Waterlogging on Drivers’ Driving Behavior—An Experimental Study Based on High-Fidelity Driving Simulator

“…In terms of the impact of rainfall on traffic flow, it can be seen that rainfall creates decreased vehicle speeds, and the speed reduction effect increases when the rainfall intensity is larger [7][8][9][10][11]. Similar effects still apply to traffic capacity when faced with rainfall, in that the traffic capacity is also inversely correlated with rainfall intensity [12][13][14][15]. Some scholars, such as Li et al, studied the effects of rainfall intensity coupled with traffic flow density on the stability of drivers' driving speeds, and found that rainfall intensity reduces the speed stability when vehicle density is low, while rainfall intensity strengthens the speed stability when vehicle density is high [16].…”

Predicting the duration and impact of the non-recurring road incidents on the transportation network

“…Mashros et al [79] [80] analyzed the correlation of rainfall with both traffic flow and speed data from Malaysia, which is a tropical country like Singapore. They considered daylight off-peak hour traffic data in one study [79], whereas the night-time traffic is considered in another study [80]. However, their analysis excludes a large subset of rainfall instances since they did not consider the peak hour data.…”