Windshields must be made of safety glass and may not be covered or treated with any material which has the effect of making the windshield reflective or in any way non-transparent. if must be free of any not required by law. magnets stickers paint scratches

Answers: stickers

Sometimes, stickers are required to be placed on your car by law. These stickers indicate something important that traffic officers or other drivers need to be made aware of. However, stickers not required by law should not be put on windshields. This is because the visible area of windshields should not be diminished. Doing so may result in hazardous driving and traffic accidents.