Montana Window Tint: 24% Front, 14% Rear, and No Inspection Lane to Catch It

The tint rule is buried inside a section with a long catchline: 61-9-405, MCA, "Windshields required, exception -- unobstructed and equipped with wipers -- window tinting and sunscreening -- restrictions -- exemptions -- definitions." Subsection (4) carries the numbers and it applies to a person operating a motor vehicle that is required to be registered in Montana upon a highway. Front side windows fail if the sunscreening or other transparent material has a luminous reflectance of more than 35% or light transmission of less than 24%. The rear window and side windows behind the front seat fail at the same 35% reflectance but at light transmission of less than 14%, and the statute then removes an entire class from that rear limit: it does not apply to the rear window or side windows behind the front seat on a multipurpose vehicle, van or bus. Subsection (5)(d) defines a multipurpose vehicle as a motor vehicle designed to carry 10 or fewer passengers that is constructed on a truck chassis or with special features for occasional off-road use, which sweeps in a large share of the SUVs and pickups on Montana roads.

The windshield is handled separately in 61-9-405(4)(a). Sunscreening material below the AS-1 line must be clear and transparent, and above the AS-1 line it must not be red, yellow or amber in color. Montana does not state an inch measurement from the top of the glass, so the AS-1 line marked by the glass manufacturer is the operative boundary. Subsection (4)(d) adds that the windows of a camper, motor home, pickup cover, slide-in camper or other motor vehicle must meet the federal safety glazing standards in 49 CFR 571.205.

Factory glass is not automatically safe. Subsection (6) provides that, except as subsection (7) allows, subsection (4) applies to all vehicles equipped with tinted windows, including windows with less than 100% light transmission to which additional sunscreening material has been applied. In other words, film added over privacy glass is measured as the finished stack. Subsection (7) then carves out the exemptions: subsection (4) does not apply to a multipurpose vehicle equipped with tinted windows installed by the manufacturer, or to a hearse, ambulance, government vehicle, or any vehicle carrying a currently valid certificate of waiver affixed under 61-9-428. It also directs that a certificate of waiver must be issued by the department for a vehicle that was registered in Montana on October 1, 1991 and was equipped on that date with a sunscreening device or material that subsection (4) would prohibit.

The waiver route is unusual and worth knowing precisely. Under 61-9-428, MCA, it is the Montana Highway Patrol or a local law enforcement agency, not the Motor Vehicle Division, that may grant a waiver of the 61-9-405(4) standards, and it may do so for reasons of safety or security or for medical reasons based on an affidavit signed by a licensed physician, licensed physician assistant, or advanced practice registered nurse as defined in 37-8-102, MCA. The waiver must be in writing and must carry the vehicle identification number, registration number or other clear description of the vehicle, the date issued, the owner's name, the reason for granting it, the dates it is effective, and the signature of the officer granting it. The issuing agency keeps a copy until the waiver expires. Chapter 242, Laws of 2007, added physician assistants and advanced practice registered nurses to the list of who may sign the affidavit.

Enforcement in Montana is roadside and only roadside. There is no periodic safety inspection for private vehicles: part 5 of Title 61, chapter 9 contains just two inspection provisions, and 61-9-502 is the semiannual school bus inspection while 61-9-501 lets the department or its agents require a driver to stop and submit to an inspection only "upon reasonable cause to believe that a vehicle is unsafe or not equipped as required by law." If a defect is found, 61-9-501(3) requires a written notice specifying the deficiencies and requiring the vehicle be put right within 5 days. Nor does the administrative code fill the gap: the Highway Patrol's equipment rule, ARM 23.3.416, adopts the American Association of Motor Vehicle Administrators approval agreement and contains no light-transmittance figure at all. A meter reading taken at the kerb is therefore the whole of tint enforcement in Montana.

Section 61-9-429, MCA, creates two separate offenses. Under subsection (1), a person who owns or operates a motor vehicle in violation of 61-9-405(4) is guilty of a misdemeanor punishable as provided in 46-18-212, MCA, which allows a term of imprisonment not to exceed 6 months in county jail or a fine not to exceed $500, or both. Under subsection (2), the installer is separately liable: a person who applies sunscreening material or glass-plastic glazing material in a manner that results in a window violating 61-9-405(4) commits the same misdemeanor, which puts the tint shop as well as the driver in the frame.

Because 61-9-429 supplies its own penalty, the graduated fine ladder in 61-9-511 for equipment offenses generally does not govern here. A roadside stop that reveals non-compliant film also triggers 61-9-501(3), so the driver receives a written notice specifying the deficiency and requiring correction within 5 days, with a copy sent to the department. A driver with a medical or security need should obtain the 61-9-428 waiver in advance and keep the certificate affixed to the vehicle, since 61-9-405(7) exempts only a vehicle to which a currently valid certificate is affixed.