However, there are some serious shortcomings that most people don't always heed.
One problem is that GPS considers some roads to be passable and will give directions, but the roads require off-road vehicles or are impassible to all vehicles at certain times of year. That's a situation I encountered on one trip, where the GPS squawked that we should go down a gravel road to reach a national park, but it became impassible for our sedan. Only after backtracking and taking another route, did we reach the national park and saw where the gravel road would have let out (and that road did have a sign warning for off-road/high clearance vehicles only).
Another problem is when the GPS doesn't consider vehicle height when designing the route. That's a possible contributory factor in a deadly crash this past weekend in upstate New York.
Driver John Tomaszewski, who began working for Megabus in the spring, reportedly missed a turn for the Regional Transportation Center in Syracuse, and used a GPS device to find his way down Onondaga Lake Parkway for a way back to the station, which drivers are not authorized to use when they are lost.The GPS may have lulled the drive into a false sense of security that he would have sufficient clearance for the bus.
Investigators don't believe he braked before hitting the low-hanging bridge that crushed the top level of the double-decker bus, and he has no reason for why he missed several warning signs. Onondaga County Sheriff Kevin Walsh said, “He never saw the bridge."
Deanna Armstrong, 18, was one of four casualties in the accident, along with a Philadelphia college student, a Malaysian preacher and an information technology specialist from India. All four had been sitting in the front of the top level of the bus, which was going about 35 mph before the crash. No charges have been filed in the crash, and Megabus officials said Tomaszewski had driven that route at least eight times. Tomaszewski claims he's driven it at least 20.
This is a reason why paper maps and checking routes before attempting trips for possible road hazards is a very good idea. GPS doesn't eliminate the need to maintain good map reading skills or to be alert for possible road hazards like low road clearances.