§393.60 requires glazing in specified vehicle openings to be of a type that meets ANSI Z26.1 ("AS-1" or "AS-2" markings for windshields; AS-3 in some side applications) and to remain free from discoloration, cracks, or damage in the driver's field of view. The rule is enforced primarily through §393.60(c)–(e): no obstructions in the windshield's swept area, no cracks longer than the §393.60(e) thresholds, and no discoloration affecting visibility.
Severity weight
Severity weight 1 in the Vehicle Maintenance BASIC. The weight is low in isolation but a §393.60 finding combined with §393.78 wipers and §393.79 defrosters produces a cluster that auditors treat as a visibility-program failure.
Specific limits
- A crack longer than ¼ inch in the windshield is a finding when it crosses the driver's swept area.
- Stone-strike damage where the largest dimension exceeds ¾ inch in the swept area is a finding.
- Aftermarket tint on the windshield (above the AS-1 line) is a finding regardless of light transmittance.
How to prevent it
- Replace windshields promptly when cracks begin to spread. The temperature-cycle of an over-the-road truck spreads cracks fast.
- Avoid suction-cup or adhesive accessories in the swept area — they are §393.60(d) obstructions in their own right.
- Verify aftermarket glass carries an ANSI Z26.1 marking before installation.
How Roadworthy HQ helps
§393.60 findings logged in Roadworthy HQ link to the vehicle, retain the §396.9(d)(3) repair certification, and surface alongside §393.78/§393.79 visibility-cluster findings in the audit binder.