Most states have very different laws regarding the usage of stickers and other obstructive objects placed on the windshield of cars. Sticker usage is most commonly seen on company cars looking to advertise their brand or product on official vehicles, and street-racers and similar car enthusiasts who enjoy aftermarket tuning of their cars.

The placement and size of windshield stickers are regulated by laws in California mainly through the following law excerpt below.

According to California laws, you are allowed to have stickers on your car’s windshield under the following conditions:

Stickers are permitted if stickers are a maximum 7-inch square, placed in the lower left corner of the windshield farthest removed from the driver, or a maximum 5-inch square placed in the lower corner of the windshield nearest the driver.

Other related laws that may apply to windshields include window tinting and obstructing driver view:

• According to California tint laws you can have a 5-inch strip on top of the windshield.
• Windshield obstruction laws also clearly state that no object may interfere with driver’s clear vision of the road.