Marvels of the digital age aren't always so marvelous when they mix with driving. Cell phones, for example, have hastened responses to innumerable roadway emergencies, but thousands of accidents and deaths also have been caused by people dialing cell phones or texting while driving.

Now a growing trend highlights a mixed blessing of another technology, global positioning system navigation, which was created specifically to help people - whether they are in military jets, cargo ships or passenger cars - to reach their destinations by the most direct routes.

The devices are especially appreciated by the trucking industry, for which lost time often is lost money. GPS devices help drivers find the most direct routes and alternative routes when the best routes are blocked by construction or crashes.

Several states have reported increases in tractor trailers crashing into low overpasses. It's a particular problem in some Eastern states with narrow, older roads and low bridges and, especially New York, where parkways were designed with low overpasses to exclude big commercial vehicles.

According to U.S. Sen. Charles Schumer of New York, 43 trucks hit overpasses on Long Island alone in 2011. A study by the New York Department of Transportation found that 80 percent of such accidents in 2009 resulted from drivers following GPS directions onto roads that can't safely accommodate commercial vehicles.

Even when such crashes don't causes injury or death, they are costly in terms of lost time due to traffic tie-ups, and damaged cargo and vehicles.

Many GPS providers offer software to trucking companies that identifies restricted roads, but it often is sold at a premium.

Mr. Schumer asked the Department of Transportation to conduct a national study to determine the degree to which GPS contributes to truck crashes on roads where trucks don't belong, and to recommend solutions. One he advocates is to require GPS providers to include standard data on truck-restricted roads in their commercial products.

States, meanwhile, can attend to emphatic signage and exit ramp modifications to prevent drivers of big trucks from taking their GPS devices' inadvertent bad advice.