--- title: "What Is the AS-1 Line on a Windshield?" canonical: "https://carglassfix.com/as1-line-on-windshield/" author: "Garrett Ross" published: "2026-10-24T09:48:49+00:00" modified: "2026-10-24T09:49:11+00:00" language: "en-US" site: "CarGlassFix" description: "The AS-1 line marks where a windshield must pass 70% of light. See how to read the AS1 arrow, why it has no fixed inch height and which states use it." categories: "Front Windshield" attribution: "CarGlassFix (https://carglassfix.com/)" --- # What Is the AS-1 Line on a Windshield? Short answer The AS-1 line is the lower edge of the tinted or opaque area at the top of a windshield. The glass maker marks it with AS1 and an arrow. Below the line, the glass must let through at least 70% of light under FMVSS 205. Federal rules give the line no fixed distance in inches from the top. ## Key takeaways - Below the AS-1 line, a windshield must let through at least 70% of light; above it, FMVSS 205 sets no light limit. - The mark reads A↓S1: the arrow’s base touches a short horizontal line, and the arrow points into the clear zone. - FMVSS 205 places the line with SAE J100 or a plane tilted 7 degrees through a reference point, so no federal rule puts it 5 or 6 inches down. - Texas and Ohio stop a windshield tint strip at the AS-1 line or 5 inches from the top, whichever is closer to the top. - NHTSA says a windshield with no AS-1 line must let through at least 70% of light across the whole glass. ## What the AS-1 line is The AS-1 line is a permanent mark on a windshield that shows where the glass must start letting through at least 70% of light. NHTSA, the federal vehicle safety agency, explained the rule in a 2011 letter to a state trooper in Virginia. FMVSS 205, the federal glazing standard, requires car glass to meet ANSI/SAE Z26.1-1996. That industry standard requires at least 70% light transmittance in every area needed for driving visibility. FMVSS 205 allows two darker areas near the top of the windshield: a tinted shade band and the opaque area where the rearview mirror is mounted. Glass in those areas may let through less than 70% of light. Section 7 of Z26.1 then requires a permanent AS-1 mark where the darker area ends. The federal standard covers new vehicles and new glass. Rules for tint added later come mainly from state law, plus FMCSA rules for trucks and buses. Several states use the AS-1 line as the lowest point for a tint strip. ## Where the AS-1 line sits and how it is marked The AS-1 line sits near the top of the windshield, at the lower edge of the shade band or the mirror-mount area. FMVSS 205 shows the mark as “A↓S1”, with the arrow between the A and the S. The base of the arrow touches a short horizontal line, and that line is the boundary. NHTSA says the arrow points to the area with more than 70% light transmittance. On a windshield, that area is below the line, so the arrow points down. ![Windshield diagram of the AS-1 line: the shade band and mirror area above the line may pass less than 70% of light, the glass below must pass at least 70%, and the A-arrow-S1 mark has the arrow's base on a short horizontal line pointing down into the clear zone; FMVSS 205 places the line with SAE J100 or a plane tilted 7 degrees through point V1, 3 degrees in the center 300 mm](https://carglassfix.com/wp-content/uploads/2026/10/as1-line-windshield-marking.webp) *The AS-1 mark and the two zones it separates, from FMVSS 205 (S5.1.3, S5.3) and NHTSA interpretation 11-000697. Diagram: CarGlassFix.* On a windshield with no shade band, the line marks the lowest point of the opaque area at the top center, where the mirror is mounted. NHTSA set out both cases in its 2011 letter. Use these steps to find and measure the line on your own car. ## How to find and measure the AS-1 line on your windshield 1. ### Look along the top of the glass Check both sides and the area around the mirror for a small AS1 mark with an arrow. 2. ### Read the arrow The short horizontal line touching the arrow’s base is the AS-1 line. 3. ### Measure from the top Run a tape measure from the top of the windshield straight down to that line. 4. ### Compare it with your state Texas and Ohio stop a strip at the line or 5 inches, whichever is closer to the top. Virginia uses 3 inches when there is no line. 5. ### Check again after a replacement Measure the line on the new glass before a tint strip goes back on. ## Why there is no standard number of inches No federal rule puts the AS-1 line at a set distance from the top of the windshield. FMVSS 205, section S5.3, gives glass makers two ways to place the lower edge of a shade band. The first is SAE Recommended Practice J100 (1995), titled “Passenger Car Glazing Shade Bands”. The second is a plane tilted upward 7 degrees from the vehicle’s X axis, passing through a reference point called V1. The coordinate system and point V1 come from UN ECE Regulation 43. In a strip 300 mm (about 11.8 inches) wide at the center of the windshield, the plane tilts 3 degrees instead. The angle method starts from a point on the vehicle. FMVSS 205 contains no inch figure for the line at all. Several tint and glass-shop pages say the line is usually 5 to 6 inches down. Some AI search answers repeat that figure. The table checks the most common claims against the primary texts. | Common claim online | What the primary text says | Source | | --- | --- | --- | | The line is usually 5 to 6 inches from the top | The line is placed with SAE J100 or a 7-degree plane through point V1. No inch figure is given. | FMVSS 205, S5.3 | | Some states use the top 5 inches instead, with a similar effect | Texas and Ohio apply the AS-1 line and 5 inches together, whichever is closer to the top | Tex. Transp. Code 547.613; Ohio Admin. Code 4501-41-03 | | The line can look like a dotted frit band | The mark is AS1 with an arrow whose base sits on a horizontal line | FMVSS 205, S5.1.3 | | AS1 is the highest safety rating | AS1 is the glazing class approved for use anywhere in a vehicle, including the windshield | Virginia State Police, from Z26.1 and FMVSS 205 | | The glass below the line meets stricter impact tests | The line separates light zones. The arrow marks the part that passes the light transmittance test (Test 2). | FMVSS 205, S5.1.3; NHTSA 2011 | ## State rules that use the AS-1 line Texas, Ohio, Virginia, New Jersey and Florida all name the AS-1 line in their windshield rules, and each one words the limit differently. Texas and Ohio add a 5-inch cap. Virginia adds a 3-inch fallback for glass without a line. California does not use the line and measures from the driver’s seat. ![Chart of how far down a windshield tint strip may reach: Texas and Ohio stop at the AS-1 line or 5 inches, whichever is closer to the top, so a line 4 inches down allows 4 inches and a line 6 inches down still allows only 5; Virginia uses 3 inches when there is no line; New Jersey and Florida use the line itself; trucks and buses keep devices within 6 inches of the top; California measures 29 inches above the driver's seat](https://carglassfix.com/wp-content/uploads/2026/10/as1-line-tint-strip-limits-by-state.webp) *Limits from the state and federal rules in the table below. Line heights of 4 and 6 inches are examples. Diagram: CarGlassFix.* | State or agency | Rule | What it says about the AS-1 line | Other conditions | | --- | --- | --- | --- | | Texas | Transp. Code 547.613(b)(1) | A windshield strip may not go below the AS-1 line or more than 5 in from the top, whichever is closer to the top | At least 25% light transmission and no more than 25% reflectance with the glass; not red, blue or amber | | Ohio | Admin. Code 4501-41-03(A)(5) | Material along the top that stays above the AS-1 line or 5 in, whichever is closer to the top, is not regulated by the rule | Other windshield film needs 70% light transmittance, plus or minus 3%, with the glass | | Virginia | 19VAC30-70-210 B.10 | Inspection rejects sunshading words, lettering, numbers or pictures below the AS-1 line | 3 in from the top when there is no line. Sunshading is permitted if Virginia DMV authorizes it and the registration shows it | | New Jersey | N.J.A.C. 13:20-1.2(b) | Sun-screening that cuts light below 70% may go on the part above the AS-1 line | Below the line, 70% minimum; the rule sits in the subchapter on medical exemption certificates | | Florida | Stat. 316.2952(2)(b) | A transparent strip at the top may not encroach on the “AS/1 portion” of the windshield | A violation is a noncriminal, nonmoving infraction | | California | Veh. Code 26708(c) | No AS-1 reference | The strip’s bottom edge must be at least 29 in above the driver’s seat; not red or amber | | Trucks and buses (FMCSA) | 49 CFR 393.60(d) | Tint is allowed if the portions marked for 70% still pass 70% | Applies to the windshield and the windows beside the driver | The phrase “whichever is closer to the top” means both limits apply at once. If the AS-1 line on a Texas car sits 4 inches down, the strip stops at 4 inches. If the line sits 6 inches down, the strip still stops at 5 inches. These rows cover only the AS-1 part of each law. For side windows, medical exemptions and the full legal question, read [is it illegal to have tint on your windshield](https://carglassfix.com/is-it-illegal-to-have-tint-on-windshield/). The trade-offs of a strip are in [pros and cons of windshield tint](https://carglassfix.com/pros-and-cons-of-windshield-tint/). ## What else can go above the line Virginia’s rules also allow devices and dealer stickers above the AS-1 line. Its inspection rules pass a navigation device, a video event recorder or a crash avoidance camera on the inside of the windshield. The whole device must sit above the AS-1 line or outside the wiper sweep. Virginia dealers may also put a transponder sticker up to 1 by 4 inches and a barcode sticker up to 3 by 4 inches on the driver’s side edge. Both must stay above the line and come off at sale or lease. Florida allows government toll devices and GPS devices on the windshield. California allows a toll or CHP device in a 5-inch square at the top center. Trucks and buses follow FMCSA rule 49 CFR 393.60. It keeps antennas and similar devices within 6 inches of the top edge and outside the wiper sweep. A strip near a factory camera raises a separate question, covered in [does windshield tint interfere with sensors](https://carglassfix.com/does-windshield-tint-interfere-with-sensors/). For sticker placement state by state, see [what the sticker on your windshield is](https://carglassfix.com/what-is-the-sticker-on-my-windshield/). ## Windshields with no AS-1 line A windshield with no AS-1 line must let through at least 70% of light across the whole glass, according to NHTSA’s 2011 letter. The same letter says that glass may still have a tinted band at the top. That band must also let through at least 70% of light. Some factory windshields lack the mark. Virginia’s inspection rules note that some 1998 and 1999 Ford Contour/Mystique, Econoline and Ranger vehicles were built without the AS-1 windshield marking. Ford certified that those windshields meet all performance standards. Virginia inspectors do not reject them. State laws handle a missing line with fixed numbers. Virginia limits lettering and dealer stickers to 3 inches from the top. In Texas and Ohio, the 5-inch cap applies on its own. FMVSS 205 requires aftermarket replacement glass to meet the same standard. If you cannot find a mark on a new windshield, ask the installer for the glass details before a strip goes on. Decorative stickers follow separate rules, covered in [can you have stickers on your windshield](https://carglassfix.com/can-you-have-stickers-on-your-windshield/). ## AS1 in the glass label is a different mark The AS1 in the glass label names the type of safety glass, while the AS-1 line marks a boundary. The label, often called the bug, usually sits in a bottom corner of the windshield. It lists the glass maker, the DOT code that NHTSA assigns, the AS code and a model number. FMVSS 205 requires the DOT symbol and the maker’s code on top of the Z26.1 marks. The Virginia State Police list of approved equipment, taken from Z26.1 and FMVSS 205, defines the main codes. | Code | Where the glass may be used | | --- | --- | | AS1 | Anywhere in a motor vehicle, including the windshield | | AS2 | Anywhere except the windshield | | AS3 | Anywhere except windshields, the windows beside the driver of a bus or truck, a bus or truck rear window used for driving visibility, and every window of a passenger car or taxi | NHTSA describes Item 1 glass, the AS1 class, as three-ply laminated glass. FMVSS 205 also lets low speed vehicles use AS-4 glazing in the windshield. To decode the rest of the label, see [how to find the manufacturing date on a windshield](https://carglassfix.com/how-to-find-windshield-manufacturing-date/). To confirm the glass type in your car, see [how to check if a windshield is laminated](https://carglassfix.com/how-to-check-laminated-windshield/). ## Frequently asked questions **How many inches down is the AS-1 line?** There is no standard number. FMVSS 205 places the line with SAE J100 or a 7-degree plane through a reference point, so you need to measure your own glass from the top down to the mark. **How dark can tint above the AS-1 line be?** It depends on the state. Texas requires at least 25% light transmission for a windshield strip, while New Jersey allows material that lets through less than 70% of light above the line. Read [is it illegal to have tint on your windshield](https://carglassfix.com/is-it-illegal-to-have-tint-on-windshield/) for the rules where you live. **What does AS1 mean on my windshield?** In the glass label, AS1 means safety glass approved for use anywhere in a vehicle, including the windshield. Near the top of the glass, AS1 with an arrow marks the AS-1 line. **What is the tint line on a windshield called?** It is called the AS-1 line. FMVSS 205 calls the tinted strip above it the shade band. **Can a dash cam go above the AS-1 line?** In Virginia, a video event recorder such as a dash cam, a navigation device or a crash avoidance camera passes inspection when the whole device sits above the AS-1 line or outside the wiper sweep. Other states write their own rules, so check before you mount one. ## Sources - [49 CFR 571.205, FMVSS No. 205, Glazing materials (eCFR)](https://www.ecfr.gov/current/title-49/subtitle-B/chapter-V/part-571/section-571.205), sections S5.1, S5.1.2, S5.1.3, S5.3, S5.4 and S6.2 (checked 24 October 2026) - [NHTSA interpretation 11-000697, letter to Trooper James S. Kile](https://www.nhtsa.gov/interpretations/11-000697trooperkile205), May 10, 2011 (checked 24 October 2026) - [49 CFR 393.60, Glazing in specified openings (FMCSA)](https://www.ecfr.gov/current/title-49/subtitle-B/chapter-III/subchapter-B/part-393/subpart-D/section-393.60) (checked 24 October 2026) - [Texas Transportation Code 547.613, Restrictions on windows](https://texas.public.law/statutes/tex._transp._code_section_547.613) (checked 24 October 2026) - [Ohio Admin. Code 4501-41-03, Specifications](https://www.law.cornell.edu/regulations/ohio/Ohio-Admin-Code-4501-41-03) (checked 24 October 2026) - [19VAC30-70-210, Virginia inspection rules for glass and glazing](https://law.lis.virginia.gov/admincode/title19/agency30/chapter70/section210/) (checked 24 October 2026) - [N.J.A.C. 13:20-1.2, Light transmittance standard for windshields and front side windows](https://www.law.cornell.edu/regulations/new-jersey/N-J-A-C-13-20-1-2) (checked 24 October 2026) - [Florida Statutes 316.2952, Windshields (2025)](https://www.flsenate.gov/Laws/Statutes/2025/316.2952) (checked 24 October 2026) - [California Vehicle Code 26708](https://california.public.law/codes/vehicle_code_section_26708) (checked 24 October 2026) - [Virginia State Police, Approved Equipment Definitions (safety glazing codes)](https://vsp.virginia.gov/wp-content/uploads/2021/07/Approved-Equipment-Definitions.pdf) - [NHTSA, 54 FR 41636 (1989), glazing items](https://archives.federalregister.gov/issue_slice/1989/10/11/41636-41657.pdf) - [Glass.com: decoding the windshield bug](https://www.glass.com/info/decoding-car-windshield-bug/)