Predicting Driver Seeing Distance in Natural Rainfall

Abstract

Four field studies were conducted in natural rainfall to develop a model for predicting distances at which drivers are able to see other vehicles in the roadway at various time periods following stoppage of a windshield-wiper stroke. The seeing distance prediction was developed as a function of rain intensity, rain accumulation time, and ambient daylight illumination. Two situations were studied; in the first, drivers seated in a stationary vehicle detected moving vehicles, and in the second, moving drivers detected a stationary vehicle. Useful seeing distance models were developed from the field studies. Seeing distances predicted from the models developed from these earlier studies were compared with seeing distances obtained in a subsequent validation field test. Results indicated that average error in the prediction of seeing distances ranges from 9% to 23%.

Analysis of Nonsevere Crashes on Two- and Four-Lane Urban and Rural Highways: Effects of Wet Pavement Surface Condition

“…As the rainfall intensity increases, the drivers' visibility decreases, which in turn increases the crash risk [12][13][14][15]. Based on these studies, the influence of rainfall intensity on drivers' visibility was associated with the water film on the windshield [16], the condition of the wipers, and splash from one vehicle to another.…”

Driving in the Rain: A Survey toward Visibility Estimation through Windshields

“…According to the UK Met Ofce [15], there are four types of rain intensity classes, namely, light rain (LR)-less than 0.5 mm h − 1 ; moderate rain (MR)-2 to 10 mm h − 1 ; heavy rain (HR)-10 to 50 mm h − 1 ; and violent rain (VR)-greater than 50 mm h − 1 . Te raindrop must be larger than 0.5 mm in diameter to be classifed as rain, and the visibility distance in rain decreases as the intensity of the rain increases [16,17], and this tends to be due to the physical properties of the rain (PoR) hitting the windshield, which tends to blur and distort the background and objects [18]. Additionally, rain decreases the refectivity of most materials.…”

“…Similarly, in [16], the authors studied the visibility of the target cars from a distance during natural rains. Te observers were mounted on a vehicle and were alerted when they identifed a target vehicle when their wipers were active or had just stopped.…”

Headlight Use

“…The darker it is, of course, the more one needs headlights to see and be seen. Bhise et al (1981) report that the ability to see a parked automobile increases with increasing ambient illumination.…”

“…When visibility is low due to precipitation more drivers may use headlights under the same ambient light levels and road conditions than when visibility is good. Bhise, et al, (1981) report that seeing distance in rain depends (in addition to ambient lighting) on whether the rain is light, moderate or heavy, and on the speed of the windshield wipers.…”