India, Oct. 28 -- A sharp curve on Pennsylvania's Route 611 had a persistent safety problem that conventional road signs and markings could not solve. When rain covered the pavement, drivers faced a combination of low surface friction and difficult road geometry, increasing the risk of skidding and leaving the roadway. In 2007, the Pennsylvania Department of Transportation (PennDOT) tried a more targeted solution: a high-friction surface treatment on about 800 feet of the curve.

The Federal Highway Administration (FHWA) recorded no wet-pavement crashes at the treated location for the eight years following installation, a dramatic change from its earlier crash history. The result became an important early example of how improving the tire...