Md. Code, Transportation § 21-1412
Md. Code, Transportation § 21-1412
in effect(a) Except at the direction of authorized personnel, vehicular traffic may not cross the double white lines that designate the vehicular traffic lanes in a tunnel.
(b) Except at the direction of authorized personnel, trucks and slow moving vehicles may be driven only in the right lane of a tunnel.
(c) The driver of a vehicle may not sound his horn or flash his headlights in a tunnel.
(d) While in a tunnel, a person may not use any cutout or other device that allows exhaust gases to escape a motor without passing through a muffler or silencer.
Source: Open US Law by Vaquill AI (CC BY 4.0)URL: https://mgaleg.maryland.gov/mgawebsite/Laws/StatuteText?article=gtr§ion=21-1412&enactments=falseFetched: 10/17/2026