But not much longer. Last month, the U.S. Federal Highway Administration released its updated 1,100-page manual, which includes rules regulating signs and other traffic control devices.

The creation of safe and legible road signs is an art, but the 10 traffic guideposts below demonstrate not all sign makers are Michelangelo. Whether because of confusing symbols, contradictory ...

The National Academy of Sciences, however, measure the response of 120 people to look at a variety of road signs. The Academy concluded that straightforward road signs were the most effective.