MUTCD R9-23bL · Regulatory signs
Requires bicycles making left turns to use designated turn box
What it means
Requires bicycles making left turns to use designated turn box.
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 R9-23bL.)
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.
- R9-20 Bicycles are allowed to use the full traffic lane
- R9-21 Requires bicycles to use only the road shoulder area
- R9-22 Requires bicycles to exit the roadway or facility
- R9-23 Requires all bicycle turns to be made from the designated bike lane
- R9-23cL Alternative design requiring bicycles making left turns to use designated turn box
- R9-24 All bicycle turns using diagonal right arrow direction
