MUTCD R10-10bL · Regulatory signs
Left lane signal control
What it means
Indicates left lane signal control.
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 R10-10bL.)
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.
- R10-6aR Alternative design indicating where to stop on red for right side
- R10-7 Prohibits vehicles from blocking the intersection
- R10-8 Instructs drivers to use only the lane with the green arrow signal
- R10-10a U-turn signal control
- R10-10bR Right lane signal control
- R10-10cL Left turn lane signal control
