The AS1 line is a small marking often a row of hash marks or the letters “AS1” running a few inches below the very top of your windshield. Everything below this line must remain crystal-clear for maximum driver visibility; any tint above it forms the legal “sun-visor strip.”
Why Drivers Should Care
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Stay street-legal: Most U.S. states ban tint below the AS1 line. Violations can lead to tickets or failed inspections.
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Protect visibility: The zone under the line meets strict ANSI safety requirements for light transmission (70 % or higher) and impact resistance, ensuring an unobstructed forward view in bright sun, rain, or at night.
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Preserve windshield strength: AS1-approved glass is engineered to absorb impact without shattering toward occupants vital for air-bag deployment and roof support.
AS1, AS2 & AS3 – What the Codes Really Mean
| Code | Typical Location | Light Transmission | Impact Resistance | Best Use Case |
|---|---|---|---|---|
| AS1 | Windshields | ≥ 70 % | Highest (federal standard FMVSS 205) | Full forward visibility |
| AS2 | Front & rear side windows | ≥ 70 % | Moderate | Day-to-day side visibility |
| AS3 | Rear side & back glass | < 70 % (privacy tint) | Lower | Heat & glare reduction, privacy |
Note: Only AS1 glass is legal for the main windshield viewing area.
How to Spot the AS1 Line on Your Car
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Look high: Peer a few inches down from the upper windshield edge; you’ll see faint dashes, dots, or “AS1.”
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Check the mirror zone: The line generally aligns with or sits just above the rear-view mirror mount.
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Wiper reach test: Raise a wiper; the arc usually stops right at or slightly below the AS1 boundary.
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Read the label: Many OEM windshields etch ‘LAMINATED AS1’ in one corner for easy ID.
If you can’t find the mark, measure a 5- to 6-inch band from the top edge that’s the accepted AS1 visor strip in most states.
Tinting Rules Made Simple
| Region | Common Rule of Thumb* |
|---|---|
| Most U.S. States | No tint below AS1 line (or top 5–6 in.) |
| Canada | Similar AS1 guidelines; some provinces ban any windshield tinting |
| Europe | 75 % minimum visible light transmittance (VLT) below visor band |
FAQ: Fast Facts for Everyday Drivers
- Can I install a darker tint above the AS1 line?
Yes, many states let you black out the visor strip as long as the band stays above AS1 and doesn’t intrude on wiper sweep. - Does replacing my windshield affect the AS1 line? Quality replacements carry the same AS1 marking. Choose OEM-grade laminated glass to retain safety ratings.
- Will a heads-up display work through AS1 glass? Absolutely. AS1 windshields maintain high clarity, ensuring HUD projections remain sharp.
