Anyone who has ever had trouble reading a highway will appreciate the decade-long effort to change the lettering that has signaled exits and avenues along U.S. highways for half a century.

More than six formal studies and dozens of field reviews led to the new Clearview road signs that researchers say provide a 20 percent improvement in legibility and recognition.

"Clearview achieves its greater legibility by using upper and lower case with initial capital letters, special spacing based on how a viewer reads a legend from an extended distance and by eliminating nighttime overglow or halo-ing," says Martin Pietrucha, a civil engineer at Penn State University.

Overglow is the glare around the letters on a sign from a car's headlights. This makes traveling at night particularly worrisome for many older drivers.

Clearview lettering diminishes the effect, thereby improving how quickly a driver can read a sign and make a decision.

One of the new signs on a highway in Pennsylvania. Credit: Greg Grieco, Penn State

"Although Clearview was intended to help older drivers, our studies show that the appreciable gain in reaction time provided by the new typeface will be achieved by drivers regardless of age," Pietrucha said.

The new signs are already in use along Routes 322 and 80 in Pennsylvania near Penn State, as well as along highways in Texas and Canada.