# Transportation (GTR)

## Title 21. Vehicle Laws -- Rules of the Road

### Subtitle 11. Miscellaneous Rules

#### Section 21-1131

(a) Except as provided in subsection (b) of this section, a person may not knowingly or intentionally cause a diesel-powered motor vehicle to discharge clearly visible smoke, soot, or other exhaust emissions onto another person or motor vehicle.

(b) This section does not apply to a person operating:

  (1) A diesel-powered vehicle that discharges visible exhaust as the result of normal acceleration or towing;

  (2) A commercial vehicle with a gross weight of 10,000 pounds or more; or

  (3) A construction vehicle operating at a construction site.

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Md. Code Ann., Transp. (as displayed at mgaleg.maryland.gov, October 16, 2026)