Number plates, further violations
No other numbers to be exposed
13 (1) No number other than that upon the number plate furnished by the Ministry shall be exposed on any part of a motor vehicle or trailer in such a position or manner as to confuse the identity of the number plate. R.S.O. 1990, c. H.8, s. 13 (1).
Number plate to be kept clean
(2) Every number plate shall be kept free from dirt and obstruction and shall be affixed so that the entire number plate, including the numbers, is plainly visible at all times, and the view of the number plate shall not be obscured or obstructed by spare tires, bumper bars, any part of the vehicle, any attachments to the vehicle or the load carried. 1994, c. 27, s. 138 (7).
Obstruction prohibited
(3) The number plates shall not be obstructed by any device that prevents the entire number plates including the numbers from being accurately photographed using a photo-radar system. 1993, c. 31, s. 2 (5).
Same
(3.0.1) The number plates shall not be obstructed by any device that prevents the entire number plates including the numbers from being accurately photographed using a red light camera system. 1998, c. 38, s. 2 (1).
Same
(3.1) The number plates shall not be obstructed by any device or material that prevents the entire number plates including the numbers from being identified by an electronic toll system. 1996, c. 1, Sched. E, s. 2 (1).
Offence
(4) Every person who contravenes subsection (2), (3), (3.0.1) or (3.1) is guilty of an offence. 1993, c. 31, s. 2 (5); 1996, c. 1, Sched. E, s. 2 (2); 1998, c. 38, s. 2 (2).

for California
(f) A covering shall not be used on license plates except as follows:

(1) The installation of a cover over a lawfully parked vehicle to protect it from the weather and the elements does not constitute a violation of this subdivision. Any peace officer or other regularly salaried employee of a public agency designated to enforce laws, including local ordinances, relating to the parking of vehicles may temporarily remove so much of the cover as is necessary to inspect any license plate, tab, or indicia of registration on a vehicle.

(2) The installation of a license plate security cover is not a violation of this subdivision if the device does not obstruct or impair the recognition of the license plate information, including, but not limited to, the issuing state, license plate number, and registration tabs, and the cover is limited to the area directly over the top of the registration tabs. No portion of a license plate security cover shall rest over the license plate number.

A casing, shield, frame, border, product, or other device that obstructs or impairs the reading or recognition of a license plate by an electronic device operated by state or local law enforcement, an electronic device operated in connection with a toll road, high-occupancy toll lane, toll bridge, or other toll facility, or a remote emission sensing device, as specified in Sections 44081 and 44081.6 of the Health and Safety Code, shall not be installed on, or affixed to, a vehicle.
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(f) A covering shall not be used on license plates except as follows:

(1) The installation of a cover over a lawfully parked vehicle to protect it from the weather and the elements does not constitute a violation of this subdivision. Any peace officer or other regularly salaried employee of a public agency designated to enforce laws, including local ordinances, relating to the parking of vehicles may temporarily remove so much of the cover as is necessary to inspect any license plate, tab, or indicia of registration on a vehicle.

(2) The installation of a license plate security cover is not a violation of this subdivision if the device does not obstruct or impair the recognition of the license plate information, including, but not limited to, the issuing state, license plate number, and registration tabs, and the cover is limited to the area directly over the top of the registration tabs.

A casing, shield, frame, border, product, or other device that obstructs or impairs the reading or recognition of a license plate by an electronic device operated by state or local law enforcement, an electronic device operated in connection with a toll road, high-occupancy toll lane, toll bridge, or other toll facility, or a remote emission sensing device, as specified in Sections 44081 and 44081.6 of the Health and Safety Code, shall not be installed on, or affixed to, a vehicle.
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