MUTCD W16-21P · Warning signs
Supplemental plaque indicating '2-Way Bicycle Cross Traffic'
What it means
Supplemental plaque indicating '2-Way Bicycle Cross Traffic'.
What to do about it
It is a warning sign: the yellow diamond warns of a condition ahead so you can slow down and be ready before you reach it. (MUTCD W16-21P.)
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 warning signs series — the ones most easily mixed up with it.
- W16-17P Supplemental plaque indicating 'Toll'
- W16-18P Supplemental plaque indicating 'Notice'
- W16-19P Supplemental plaque indicating 'Last In Corridor'
- W16-20P Supplemental plaque indicating 'Except Bicycles'
- W17-1 Speed hump ahead on the roadway
- W18-1 There are no traffic control signs ahead at intersection
