Some studies of retro-reflective materials on road signs from the drivers perceptual point of view. Presented at the 15th World Road Congress, Mexico, October 1975.

Nowadays, most signs are reflectorized and many are separately lighted. One of the main questions in this study is whether the separate lighting can be replaced by using improved, high luminance retro-reflective materials. The general problem dealt with in this study is to establish to what extent the new retro-reflective sheetings with about 3 times higher photometric values than the standard sheetings used so far can improve and benefit road signing.