Windshield tint strips: how to check the AS-1 line and size limit
There is no single legal windshield-strip size for the whole country. Some rules refer to an AS-1 boundary. Others use an inch measurement or explain how the two interact. Use the rule that applies to your vehicle, then locate its boundary before the film is cut.
The dark band built into a windshield, a printed glass marking and an added tint strip are not automatically the same thing.
What is a windshield tint strip?
A tint strip is a band of added material near the top of the windshield. People also call it a sun strip, visor strip or brow. It covers a smaller area than film applied across the whole windshield.
That difference matters. A rule allowing material in the upper band does not necessarily allow the same material lower down in the driver’s forward view.
Before discussing shade or shape, ask which legal boundary the installer will use. “We always cut them this wide” does not explain the rule for your vehicle.
What does the AS-1 line tell me?
Some state provisions refer to an AS-1 boundary when describing the allowed upper area. Locate the actual windshield marking and ask the installer to explain how it relates to the rule.
Do not treat an AS-1 marking as a nationwide permission slip. The state may also regulate the material, color, reflectance or transmission. The boundary answers where a strip may go; it does not answer every other question.
If the mark is hard to find, ask for help identifying it. A mark on another vehicle or a picture online may not resolve your windshield.
Why “five inches” is not a universal answer
Texas law says the strip cannot extend below the AS-1 line or more than five inches from the top, whichever boundary is closer to the top. North Carolina’s statute uses five inches or the AS1 line, whichever measurement is longer. Those instructions are not identical.
New York’s windshield provision refers to an uppermost six-inch band. These examples show why copying a measurement from a national chart can lead you wrong. Read the complete provision, including vehicle-year and other conditions, before relying on one line in a summary.
The state-law directory links to the relevant guide and official sources.
What if my windshield has no AS-1 line?
Do not invent a fallback. Check whether the applicable rule provides one. If it does, follow that particular rule. If it does not clearly answer the situation, ask the responsible agency before installation.
Tell the agency your vehicle’s year, make and model, whether the glass was replaced, and what marking is present. A clear description is more useful than asking whether a generic “sun strip” is legal.
You do not need to remove trim or scratch the glass to search for a mark. Let a glass professional inspect it if necessary.
Can the strip be darker than the side windows?
It may have a separate rule, but do not assume unlimited darkness. Check its own material and optical conditions. A side-window percentage does not automatically apply to the windshield band.
Also check the proposed strip from the normal driving position while parked. A legal boundary is not a reason to accept a placement that causes a visibility problem for you. Explain any concern before authorizing the work.
A simple way to approve the scope
Ask the installer to show where the bottom edge will sit and identify the rule used. Confirm the product, shade and any required label or record. Keep those details with the invoice.
If you want a curved or decorative strip, ask how its lowest point relates to the permitted boundary. A design choice should not quietly extend the material farther into the viewing area.
If a strip is already fitted and you are unsure about its size, arrange a check rather than judging from the passenger seat or a photo. For questions about film across the remaining glass, use the separate windshield tint guide.
Frequently asked questions
Is every five-inch windshield tint strip legal?
No. The relevant state may use a different boundary or impose other conditions. Check the rule for your windshield before choosing the width.
Can the factory shaded band be used as the cutting line?
Do not assume so. A built-in shaded area is not necessarily the boundary named in the applicable rule. Ask the installer to identify the correct reference.
Does an AS-1 line permit tint below it?
Not by itself. A rule referring to the line must be read in full. Permission for clear material or another exception is a separate question.