No Bicycles sign
Cyclists may not ride on this road, path or bridge.
Federal designation R5-6 in the MUTCD, the national standard every state signs to. Posted at the entrance ramps of freeways and on structures like tunnels and elevated bridges that have no usable shoulder.
How to recognise it
This sign is a tall rectangle in white, the standard background for a rule you must obey. These carry the force of law. Ignore one and you have broken a traffic rule, not just a guideline. Most are white rectangles with black text, and the handful that are not, the stop and yield signs, get their own unmistakable shapes.
What the test wants you to know
This sign is easy to confuse with a bicycle warning sign because they share the same bicycle symbol, but the red slash and white regulatory background are what make it a prohibition rather than an alert to watch for riders. It typically appears on limited access highways and certain bridges and tunnels where a shoulder is not safe for cyclists.
Practise it
Reading about a sign is not the same as recognising it in half a second with an examiner watching. Every state road signs test on this site shows the sign and asks you to name it, then shows four faces and asks you to pick the right one.
Stop
Yield
Do Not Enter
Wrong Way
Speed Limit
One Way