MUTCD R5-1 · Regulatory signs
Prohibits entry to all vehicles
What it means
Prohibits entry to all vehicles.
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 R5-1.)
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.
- R4-20L Requires all traffic to turn left at this location
- R4-20R Requires all traffic to turn right at this location
- R4-21L This lane is designated for left turns only
- R4-21R This lane is designated for right turns only
- R5-1a Traffic is traveling in the wrong direction
- R5-1b Bicycles are traveling in the wrong direction
