Nano impregnation spray is used to apply sayings to the road. These only become visible when it rains and are intended to draw attention to various problems in traffic when it rains. If it stops raining, the sayings also disappear again.
Example sentences „eyes open“, „risk of slipping“, „head up“, „caution“, „give way“, „when it rains, the braking distance of cars doubles“, „rain does not excuse going over red“.