Front Windshield Tint Rules and the AS-1 Line

What the AS-1 line is

Look at the top corner of your windshield, usually on the passenger side, and you will find a small stack of etched text. Among it is the marking "AS-1" or "AS1" with a short horizontal line. AS-1 is a glazing designation from the ANSI Z26.1 safety standard that federal rules incorporate, and that standard requires the glass the driver looks through to let at least 70% of light pass. The line marks the boundary of that area.

Above the line is the shade band, the factory-tinted strip at the top of many windshields. Below it is the clear driving area. Many state tint laws use the AS-1 line as the lowest point aftermarket film may reach. If your windshield has no visible AS-1 marking, some states substitute a fixed measurement from the top of the glass; Texas, for example, uses five inches.

Why windshield rules are the strictest

Everything you do behind the wheel depends on the windshield. Side windows matter for mirrors and blind spots, but the windshield is your view of the road, the signals, and the car ahead. Why states limit window tint explains the general reasoning; for the windshield, the visibility argument is strongest and states are least willing to compromise.

The windshield is also laminated safety glass with a plastic layer inside, designed to stay in one piece, and states prefer to keep the driver's view through it unobstructed.

What most states allow on the windshield

• A strip above the AS-1 line. Tint on the top band is commonly permitted, though some states, such as Virginia, only allow film that replaces the manufacturer's sunshield. Some states let this strip be quite dark; others cap it.
• Clear or near-clear film below the line, in some states. Kentucky, for example, allows windshield film with at least 70% light transmittance that is not red or yellow. Others, such as Virginia, allow no film below the top band without a medical authorization. Where it is allowed, this is where UV and infrared-rejecting ceramic films fit.
• Nothing reflective. Mirrored windshield film is widely restricted, and many states cap reflectivity on every window.

Specific rules vary, so start with your state's page and confirm with your state's DMV or statute. The general pattern: a strip on top, clear film or nothing below, no mirrors.

Does a medical exemption change the windshield rules?

Sometimes, and it depends on the state. Some states extend the medical exemption to the windshield; Virginia's medical authorization, for example, allows a 70% film across the entire windshield. Others leave the windshield rule untouched and apply the exemption to side and rear glass only. A few have no medical exemption at all.

This is a common question, and the honest answer is that the certificate documents a physician's finding of medical need. What that finding lets you install on each window is set by state law, and the certificate comes with guidance on the state's process. For most drivers, the biggest practical gain from an exemption is on the front side windows, where the sun hits the driver's arm and face for the whole trip.

If you need protection through the windshield in a state that does not extend the exemption to it, a clear ceramic film that cuts infrared heat may be allowed, depending on the state. Keep in mind that laminated windshields already block most UVA on their own; one study of 29 cars measured an average of 96%. Windshield film options for medical needs compares them.

Getting the exemption for the rest of the car

ShadedMD is a telehealth service for medical window tint exemptions: a physician licensed in your state reviews your online questionnaire, physicians aim to finish reviews within 24 to 48 hours, and the fee is a flat $129 with a 30-day money-back guarantee. The process is a 5-minute questionnaire and an individual review by a physician licensed in your state. If you are approved, you receive a signed PDF certificate with a Recommendation ID, valid for one year, plus guidance on any DMV form your state requires.

Sun through the driver's window is the exposure that matters most for people with lupus, photosensitizing medications, or severe light sensitivity. ShadedMD's physicians aim to review within 24 to 48 hours, and you pay once, when you submit your questionnaire. Check if you qualify.

Next steps

Find the AS-1 line on your windshield, read your state's windshield rule, and choose a clear or near-clear film for the driving area. For the side windows, if sun is a medical issue, get a physician certificate through ShadedMD before you book the tint shop. Start the questionnaire.

This article is general information, not medical or legal advice.

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