Samenvatting
Several measurements were tried to develop and effective method for measuring the truck spray. This led to the development of a technique which has proved most practical and capable of indicating the extent of a spray in terms of handy weight values per unit area. Measurements have been made of (1) the wiper frequency; (2) visual clarity of the preceding vehicle from the following vehicle; (3) photographs of the preceding vehicle, each of which directly indicates the visual obscuration rate, and studied relation between the weight measurement of spray and the visual obscuration rate.