Signs often convey important information that can improve road safety. The intent is to let bicyclists and motorists know what to expect, thus improving the chances that they will react and behave appropriately. For example, the use of a "No Parking in Bike Lane" sign is intended to keep this space clear for cyclists. Sign use and placement should be done carefully, in that overuse often results in non-compliance and/or disrespect. Excessive use of signs can also create visual clutter and lead to the intended sign and message getting "lost."

Regulatory signs, such as STOP, YIELD or turn restrictions require driver actions and are enforceable. NO TURN ON RED signs can improve safety for bicyclists (and pedestrians). Problems often occur at RTOR locations as motorists look to the left for a gap in traffic, especially if bicyclists are riding wrong way either in the street or on a sidewalk or path.

Warning signs can also provide useful information. An example is the SHARE THE ROAD sign, which serves to let motorists know that bicyclists may be on the road and that they have a legal right to use the road. This sign is typically placed along roads with significant bicycle traffic but relatively hazardous conditions for riding, such as narrow travel lanes with no shoulder, roads or streets with poor sight distance, or a bridge crossing with no accommodation for bicycles. Special signs are sometimes used to indicate the presence of a bicyclist.

All signs should be periodically checked to make sure that they are in good condition, free from graffiti, reflective at night, and continue to serve a purpose.