Windshields, like other components, are subjec tto wear during the life of the car;​ windshield wiper action, scraping of ice and the impact of small pebbles while driving will damage the glass. These defects will cause glare, which may be a contributing factor in night-time accidents. An instrument to measure the scattered light from these imperfections was introduced in a preceding paper at the 10th ESV meeting.

The present paper is a report on measurements of the stray light index of cars on the road in selected regions in Sweden, in the middle of W.-Germany and in southern W.-Germany. The regional differences were found to be significant;​ values in Sweden being more than twice as high than those in the other two regions. Relationships were found between weather conditions of the regions, parking behavior, mileage and age of the windshield and windshield wear.