MUTCD R15-4b · Regulatory signs
Restricts the left lane to light rail vehicles only
What it means
Restricts the left lane to light rail vehicles only.
What to do about it
It is a regulatory sign: it states a law you must obey, not a suggestion. Ignoring it is a citable violation. (MUTCD R15-4b.)
Practice this on the real test format
Signs are the part of the DMV written test people fail on, because reading them is a skill rather than a fact to memorize. Aprobify drills all 1034 of them, and tells you why each answer is what it is.
Get the appSign designations follow the MUTCD and the California MUTCD published by Caltrans; meanings are checked against the California Driver's Handbook (DL 600, rev. 6/2025). Edited by Fernando Aguilera. Aprobify is not affiliated with the California DMV.
Signs in the same family
These sit next to it in the regulatory signs series — the ones most easily mixed up with it.
- R15-1 Standard railroad crossing sign indicating intersection with railroad tracks
- R15-2P Supplemental plaque indicating the number of railroad tracks at the crossing
- R15-3P Supplemental plaque exempting certain vehicles from mandatory stop requirements at railroad crossings
- R15-4a Restricts the right lane to light rail vehicles only
- R15-4c Restricts the center lane to light rail vehicles only
- R15-5 Prohibits passing stopped trains at railroad crossings
