Signs that are prevalent on today's roads can be broken into major categories that include warning signs, regulatory signs, guide signs, and pedestrian and bicycle signs. Additional common signs are ones for railroad crossings and light rail transit grade crossings.
Warning signs are ones that indicate when to pay attention for a change in road conditions. These signs are traditionally yellow and can indicate anything from a sharp turn to a stop sign ahead. Regulatory signs tell the driver what to do and consist of stop signs, yield signs and speed limit signs, among many others. Guide signs help guide travelers to his or her destination. They include, but are not limited to, route number signs, distance-to-destination signs, mile marker signs and exit number signs.
Pedestrian signs indicate warnings for drivers as well as regulations for walkers and bike riders. Some examples of pedestrian signs include: yield here to pedestrian signs, bike lane ahead signs, and school crosswalk ahead. Railroad and light rail transit grade crossing signs warn drivers to be cautious of railroad and light transit tracks. Some examples of these signs are railroad crossing ahead signs, do not pass stopped train ahead signs, and light rail transit station ahead signs.