Can a Semi Truck Drive With a Cracked Windshield?
The short answer
- Under 49 CFR 393.60(c) the protected zone runs from the top of the steering wheel upward, excluding a 2 inch border at the top and 1 inch at each side of each windshield panel.
- Inside the zone a crack is allowed only if no other crack intersects it; the roadside rule states no length or width.
- A chip is allowed if a 3/4 inch disc covers it and it is at least 3 inches from any other damaged area. Two small chips 2 inches apart are a violation.
- The 1/4 inch crack width limit is in the annual inspection standard (Part 396 Appendix A), measured as a gap on one surface. Work to it, because a truck needs a passed inspection from the last 12 months.
- On FMCSA's SMS tables a 393.60(c) windshield violation carries severity weight 1; running without periodic inspection documentation carries 4.
Often yes, but only if the damage fits one of two exceptions in the federal rule. Under 49 CFR 393.60(c), the windshield of a commercial truck or bus must be free of damage and discoloration from the height of the top of the steering wheel upward, leaving out a 2 inch border at the top and a 1 inch border at each side. Inside that zone the rule allows any crack "not intersected by any other cracks" and any damaged area a 3/4 inch disc can cover, if it is not within 3 inches of another one. Below the top of the steering wheel, the section sets no damage limit at all.
Which trucks and buses the federal rule covers
The rule applies to commercial motor vehicles as 49 CFR 390.5 defines them: a vehicle used on a highway in interstate commerce that has a gross vehicle or combination weight rating, or actual weight, of 10,001 pounds or more; or is designed or used to carry more than 8 passengers including the driver for compensation, or more than 15 not for compensation; or carries hazardous material in a quantity that requires placards.
Trucks that never leave their state are usually caught by a state rule that copies the federal one. Texas, for example, in 37 Tex. Admin. Code 4.11, incorporates Parts 390 to 393 and 395 to 397 of the federal regulations "as amended through September 1, 2022", and defines interstate commerce for that purpose as "all movements by motor vehicle, both interstate and intrastate" on Texas roads. Other states adopt the rules with their own cutoffs (car rules are in the state rules index, including the Texas car rules). A personal pickup under 10,001 pounds is judged under the passenger car rules described in the AS-1 line and the driver's critical viewing area, not under 393.60.
Where the zone starts and stops
The protected area has four edges:
- Bottom: the top of the steering wheel. The zone extends "upward from the height of the top of the steering wheel".
- Top: 2 inches down. The text excludes "a 51 mm (2 inch) border at the top of the windshield".
- Sides: 1 inch in. The zone extends "from a 25 mm (1 inch) border at each side of the windshield or windshield panel".
- Every panel counts. The words "or windshield panel" mean a two piece windshield gets a 1 inch border on each side of each half, including the edges at the center post.
So damage on the passenger half above steering wheel height is inside the zone too: the text covers the full width, not only the glass ahead of the driver. How two piece and bonded truck glass is built and priced is in the guide to semi truck windshields.
The three things allowed inside the zone, read literally
The default is strict: the zone "shall be free of discoloration or damage". Anything outside an exception is a violation, including cloudy discoloration. The exceptions:
- Tint that meets paragraph (d). Coloring is allowed on the windshield and the windows immediately left and right of the driver if light transmittance is at least 70 percent. Car limits differ; see windshield tint strip laws by state.
- "Any crack that is not intersected by any other cracks." The roadside rule names no length and no width. A single crack running across the zone fits the words; two cracks that touch, or a crack with branches, do not.
- Any damaged area a 19 mm (3/4 inch) disc can cover, "if not closer than 76 mm (3 inches) to any other similarly damaged area". Two small chips 2 inches apart fail, though each would pass alone.
To check a chip, hold a 3/4 inch washer against the glass: if any part of the break, legs included, shows outside it, the exception is gone. Long legged star breaks fail most often (see bullseye versus star breaks).
Roadside rule or annual inspection: where the 1/4 inch figure comes from
Two answers circulate: any single crack is fine, or a crack must be under 1/4 inch wide. Both are federal text, from different rules. Section 393.60(c), the roadside rule, has no width figure. The 1/4 inch limit is in Appendix A to Part 396, the Minimum Periodic Inspection Standards that every commercial vehicle must pass at least once in the preceding 12 months under 49 CFR 396.17(c).
| Rule | Zone | Single crack | Chips and spacing |
|---|---|---|---|
| 49 CFR 393.60(c), on the road | Above top of steering wheel, minus 2 in top and 1 in side borders | Allowed if not intersected by another crack; no width or length stated | Covered by a 3/4 in disc, at least 3 in from other damage |
| Part 396 Appendix A item 12, annual inspection | Same zone | Allowed if "not over 1/4 inch wide" and not intersected | "Not more than 3/4 inch in diameter", at least 3 in from other damage |
| Virginia, trucks over 10,000 lb (19VAC30-70-580) | Above top of steering wheel, minus 2 in top and 1 in side borders | Rejected if over 1/4 in wide, or 1/4 in or less and intersected | Rejects any pit, chip or star over 3/4 in above the steering wheel; rejects damage within 3 in of other damage |
| Virginia, cars and light trucks (19VAC30-70-210) | Above a line 3 in up from the bottom | Judged under other items | Rejects a pit, chip or star crack over 1 1/2 in |
The width test is narrower than it sounds. FMCSA guidance asks whether a crack running through the glass at an angle, 1/4 inch or more from its outside edge to its inside edge, counts. No: "The crack, in order to fall outside the exception, would have to be a gap of 1/4" or more on the same surface of the windshield." That guidance refers to a 1/4 inch width "as defined in ยง393.60(b)(2)", a paragraph that no longer exists in that form; the current roadside text has no width figure.
Work to the stricter standard: a crack wider than 1/4 inch fails the annual inspection, and a truck without one cannot be used. Virginia shows the gap between truck and car rules: a 1 inch chip above the steering wheel passes its car inspection and fails its truck inspection. Which states run a safety inspection sorts the rest.
What a glass violation does to the carrier's record
A roadside windshield violation lands in the carrier's Safety Measurement System record under Vehicle Maintenance. FMCSA's public SMS tables weight it low:
| SMS violation code and description | Severity weight |
|---|---|
| 393.60(c) Windshield, damaged or discolored | 1 |
| 393.60(d) Windshield or windows, tinting permits less than 70% light transmittance | 1 |
| 393.78A-WS Washers, inoperative washing system | 1 |
| 393.95(f) Stopped vehicle warning devices missing or improper | 2 |
| 396.17C-PI Operating without documentation of a periodic inspection | 4 |
The crack itself is a small entry; running without a passed annual inspection is four times heavier. Washer and wiper rules are in the wiper, washer and defroster rules. Whether damage also puts a truck out of service is decided under the separate CVSA out of service criteria, so ask your safety department before dispatch.
Under 49 CFR 396.11 the driver's end of day report must list "any defect or deficiency" affecting safe operation. Wipers are named on the list; glass is not, but a crack in the zone qualifies. The carrier must repair a listed safety defect before the truck runs and certify it, and under 396.13 the next driver signs the last report. Reporting a chip the day it happens keeps it cheap.
Two chips close together are a violation even if each is tiny. The spacing test is 3 inches between damaged areas. A new strike near an old chip can make a legal windshield illegal overnight.
Cameras, antennas and decals have their own measured zones
Paragraph (e) sets measured mounting zones, unlike the general obstruction language of most car rules:
| Item | Where it may go under 393.60(e) |
|---|---|
| Antennas, transponders and similar devices | Not more than 6 in below the upper edge of the windshield, outside the wiper sweep and outside the driver's sight lines |
| Vehicle safety technology (forward cameras, lane departure, collision warning, driver cameras, GPS) | Not more than 8.5 in below the upper edge of the wiper sweep, or not more than 7 in above its lower edge, outside the driver's sight lines |
| CVSA decals and stickers required by law | At the bottom or sides, not more than 4.5 in up from the bottom, outside the wiper sweep and sight lines |
The 8.5 inch figure dates from a final rule published March 7, 2022 and effective in May 2022, which raised the limit from "not more than 100 millimeters (4 inches) below the upper edge of the area swept by the windshield wipers". Virginia's truck inspection regulation still tells inspectors to pass a camera mounted "not more than four inches below the upper edge" of the wiper sweep. Car rules for cameras are compared in where a dash cam may legally go, and moving a toll tag or camera to new glass is covered in toll tags and dash cams after a replacement. If the truck's own forward camera sits behind the glass, a replacement also triggers the steps in when calibration is required after glass work.
Repair, replace or keep running
Apply the zone first, then the damage type:
- Damage below steering wheel height. Outside 393.60(c). Repair a chip anyway; what makes a crack spread explains why.
- One chip in the zone that a 3/4 inch disc covers. Legal on the road. Repair it soon (see what makes damage repairable).
- Two breaks closer than 3 inches. A violation as it stands. The rule does not mention repairs and a filled break stays visible, so do not assume repair clears it; see how many repairs one windshield can take.
- A single crack that nothing crosses. Legal roadside, but if it is 1/4 inch wide or more on one surface it fails the annual inspection. See how long crack repair works.
- Intersecting or branching cracks in the zone. A violation under both rules. Replace the glass, or the affected half of a two piece windshield; read the quote line by line before approving it.
Replacement glass must meet FMVSS 205 and carry its marking under 393.60(a); how to read windshield markings shows where. The repair or replace tool walks a specific break through the same questions.
Where this answer stops applying
- Intrastate operations. States adopt the federal rules with their own dates and cutoffs.
- Out of service decisions follow the CVSA criteria, not reproduced here.
- State inspections. Only Virginia's rules were read for this page.
- Obstruction. An officer can still cite a crack that blocks the view under a general obstruction rule; how windshield tickets are written covers that route.
What to do next
Measure every break in the zone today: size against a 3/4 inch circle, distance to the nearest other damage, and whether any crack is crossed or wider than 1/4 inch on one surface. Write it on the inspection report and book a repair before the next dispatch. For several units, managing glass damage across a fleet lays one out, and glass claims on business and fleet policies explains commercial deductibles.
Frequently asked questions
Is a cracked windshield an out of service violation for a semi?
The federal rule, 49 CFR 393.60(c), defines when windshield damage is a violation, but whether a truck is placed out of service is decided under the separate CVSA out of service criteria that roadside inspectors apply. A violation that is not out of service still goes on the inspection report and the carrier's SMS record. Ask your safety department how they read your specific damage before dispatching the truck.
How big can a chip be on a commercial truck windshield?
Inside the zone above the steering wheel, a damaged area is allowed if a disc 3/4 inch (19 mm) in diameter can cover it and it is at least 3 inches (76 mm) from any other damaged area. Measure the whole break, including the legs of a star, and measure spacing edge to edge. Below steering wheel height the federal section sets no size limit.
Does the DOT allow a crack across the whole windshield?
The roadside rule allows "any crack that is not intersected by any other cracks" and states no length. The annual inspection standard in Part 396 Appendix A adds that the crack must not be over 1/4 inch wide. A long single crack can therefore pass the text of both rules, but it is weak glass that spreads, and an officer can still treat it under general obstruction rules.
Do DOT windshield rules apply to my pickup truck?
Only if it is a commercial motor vehicle under 49 CFR 390.5: used in interstate commerce with a weight rating or combination weight of 10,001 pounds or more, carrying more than 8 or 15 passengers depending on compensation, or hauling placarded hazmat. A personal pickup under those thresholds falls under your state's passenger vehicle rules, which use different zones and limits.
Where can a dash camera go on a commercial truck windshield?
Under 393.60(e), safety technology such as forward cameras and driver cameras may be mounted not more than 8.5 inches below the top of the wiper sweep or not more than 7 inches above its bottom, outside the driver's sight lines. Antennas and transponders must stay within 6 inches of the top edge of the glass and outside the wiper sweep.