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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%.

Three methods are described for measurement of glare from automotive chromium surfaces. The first is a performance measure: a glare illumination technique that measures at the driver's eye location the amount of light reflected to that location. The other two methods measure a surface property rather than performance. One is the standard glossmeter method of measuring gloss on flat surfaces. The other is a substitute gloss image method that measures gloss on both flat and curved surfaces. Results when using the glare illumination technique on flat and curved surfaces, with both bright and satin chromium finishes, indicated that glare decreased as surface curvature was increased. The effect of the satin finish was a reduction in glare from flat surfaces but not from curved surfaces.