This European Standard describes a method for determining the horizontal drainability of a road surface as an indicator of relatively low surface texture using the outflow meter as a stationary device. The method provides a measure of the drainability in the road/tyre contact area for use on all smooth non porous road surfaces (less than 0,4 mm mean profile depth) either in the field or in the laboratory. As the method measures the horizontal drainability of a small area of the surface only the selection of the test area should be assessed carefully so that it is representative of the general area on which the measurements are to be made.