How Do Officers Check Windshield Tint and the AS-1 Line?

What Is the AS-1 Line?

The AS-1 line is a marking on the windshield glass of many vehicles. Many state statutes refer to it when describing how far down a windshield a strip of tint may extend. Other states describe the limit differently, such as a number of inches from the top of the windshield. Because states differ, officers should always work from the statute in their own jurisdiction.

Step 1: Check Placement

Windshield rules are often about where tint sits, not just how dark it is. Officers look for the AS-1 marking on the glass, usually near the upper edge, and note whether film or tint extends below the allowed boundary. A photograph of the marking and the film edge can support the record.

Step 2: Measure Where the Law Requires It

If the statute sets a minimum VLT for the windshield, or for the area below the permitted strip, officers follow their agency's procedure for taking a reading with a tint meter. Tint-Chek meters read accurately to ±2%. The Tint-Chek PRO displays to the nearest 0.1%, but accuracy is still ±2%, so agencies should have a clear policy for borderline readings.

Step 3: Document the Check

•         The location of the film edge relative to the AS-1 marking or the statutory boundary

•         The reading, if one was taken, and which area of the glass it covers

•         Meter model and serial number, date, and time

•         Photos of the marking and film edge where agency policy allows

Keep These Points in Mind

•         Medical exemptions and special vehicle rules may apply, so check them before enforcement.

•         Confirm the current statute rather than relying on memory. A quick reference like window tint laws by state can help officers find the right starting point.

•         Tie every check back to your agency's written tint enforcement procedure.

Common Windshield Situations

•         Film strip above the marking: a placement question that the statute answers.

•         Film extending below the marking: a possible violation, depending on the state's rule.

•         Film covering the full windshield: check the statute and any exemptions.

•         Factory shade band: some windshields come with a tinted band across the top. It is part of the glass, so officers should know it exists and not confuse it with applied film.

Frequently Asked Questions

Is the AS-1 line used the same way in every state?

No. Some states reference the AS-1 line and others describe the limit in inches from the top of the windshield. Always use the statute for your jurisdiction.

Do officers always need a meter for windshield checks?

Only where the statute sets a VLT limit. Placement-based rules may be enforced by locating the film edge, so follow your agency's procedure.