In an unfamiliar city after dark, 64-year-old Mary Davis let her GPS device lead the way, police said. When it told her to make a right, evidently she did -- right onto railroad track and into the path of an oncoming train.
If not for a local officer who spotted her and urged her to leave the car, police said the outcome could have been tragic. Less than a minute after Davis climbed out the door, the train rammed into the back of her vehicle, totaling it, police said.
"It was touch and go," said John Saldano, chief of police for Leetonia, Ohio. "There was a very, very good chance we would have had a fatality on our hands."
Davis did not immediately respond to a request for comment from ABCNews.com. But Saldano said the home health care worker from Youngstown, Ohio, was driving Sunday night through Leetonia.
Since she was about 30 minutes south of her hometown, he said, she was using her GPS device to guide her. When it told her to make a right, he said she likely turned immediately on to the train track instead of onto a road about 40 feet beyond.
"She was probably relying on that GPS to get her to her destination and she made that bad turn," he said. "Once she got on the railroad track there, she was stuck."
Though Global Positioning System, or GPS, devices can be an immense help for motorists far from home, GPS mistakes -- be they the drivers' or the data's -- can sometimes lead to hazardous results, with drivers ending up on hundred-mile detours, stranded in the snow or, in the very worst cases, near death.
In December, a couple from Reno, Nev., said were they stranded for three days in the snow after their GPS device directed them onto an unplowed road in an Oregon forest.
At the time, John Rhoads, 65, and his wife, Starry Bush-Rhoads, 67, told "Good Morning America" they were driving home from Oregon "when we noticed that the snow was getting deep and we were over 30 miles into this road. We thought we didn't have much farther to go."
But their four-wheel-drive Toyota Sequoia became stuck in the snow and, with cell phones that wouldn't pick up signals, the couple had to wait three days before local officials could find them and pull them out of the snow.
In 2008, GPS directions led a nearly 12-foot-high bus carrying a girls' softball team into a 9-foot-high tunnel. According to the Seattle Post-Intelligencer, the accident sliced off the roof of the charter bus and landed 21 students and a coach in the hospital. All subsequently were treated and released.
Not all mistakes lead to such harrowing situations, but they still can result in headaches.
A Swedish couple on vacation found themselves more than 400 miles away off-track last summer when they misspelled the name of their travel destination in their car's GPS.
Intending to visit the island of Capri on the Mediterranean coast, they typed in Carpi, and powered on until they reached an industrial town in Northern Italy.
A local tourism official, Angelo Giovannini, told the Associated Press at the time, "Capri is an island. They did not even wonder why they didn't cross any bridge or take any boat."
Brad Preston, 44, from Oregon City, Ore., said he regularly experiences GPS frustration when he's not even in the car.
As many as five to eight times a week, he said, drivers would mistakenly end up in his driveway because of inaccurate mapping data.
"The Garmin device with the NAVTEQ [data] is showing a road through my property that does not exist," he said.
He first noticed the problem last fall, but said as recently as last week a driver took a wrong turn to his home.
NAVTEQ, which supplies GPS device makers with mapping data, told ABCNews.com that Preston's driveway was corrected in its database in October 2009 and was made available to its customers in the first quarter of this year.
"NAVTEQ prides itself on supplying the most accurate digital map of an ever changing world. Our mission is to provide our customers with the most up-to-date map content available today," a spokesman said in a statement.
In addition to the thousands of field analysts who document road changes, NAVTEQ's Web site includes an online Map Reporter that lets consumers report problems and suggest changes.
But NAVTEQ's mission is complicated by the process that moves its data to its clients, such as Garmin, and the on to the consumer's device.
Though it may constantly update its data base, NAVTEQ releases the new updates to its clients only four times a year.
When owners of GPS devices receive those updates depends on the plans they choose to buy from GPS manufacturers. The most expensive plans may make them eligible for all four updates, the cheaper plans may give them only one update.
Those consumers who opt for less-expensive plans might be driving around with outdated and inaccurate maps. If customers don't take the time to update the software, they could be relying on old maps even if they paid for all the updates.
Tele Atlas, a mapping data division of TomTom, said it updates its database daily and, like NAVTEQ, has its data released to customers four times a year. But it said it's working to speed up the process.
"We are committed to reducing the time it takes for a real world change to be reflected in our maps. We're focused on delivering the freshest maps and expect to deliver a 48-hour turnaround time in the near future," a spokesperson said.
Even though GPS companies are trying to make the information as accurate as possible, experts said drivers shouldn't rely on high-tech tools alone.
"Like any device, they are fallible," said Geoff Sundstrom, a spokesman for the American Automobile Association. "I think it's definitely a good idea if you're traveling in an area with which you are unfamiliar that you also have a good paper map as well as a GPS just in case you do find yourself in a situation where you are lost and your GPS isn't helping you out."
Sundstrom also suggested traveling with emergency supplies, such as blankets and water.
"We've become so accustomed to relying on our technology that we don't often think about what might occur if that technology fails us," he said. "And with that in mind we don't want to abandon some of the common-sense motoring advice that our parents and grandparents probably followed."
A Garmin spokeswoman had similar words of caution.
"[The device] is simply intended to give them navigation instructions and if they choose to follow it they are still responsible for following the rules of the road," she said. "Individuals need to make sure that they are using common sense while driving."
And perhaps those most recently in the throes of a GPS mishap realize that better than anyone.
"Mishaps with GPS are human error," said Angelique Stokes, a 54-year-old from Coos Bay, Ore.
Stokes and her husband Jack, 55, spent the night in their Nissan Xterra Sunday after following GPS directions on to an unplowed forest service road. They were trying to visit their son in Hood River, about two hours away from their starting point.
With their car stuck in the snow and their cell phones without signals, the couple decided to stay the night in the car. The next morning, after hiking four miles, they were able to receive a strong enough signal to communicate their location to their son.
But Stokes doesn't blame the Garmin for the experience. She blames herself and her husband.
"We made a wrong choice," she said. "We made the choice to go over the mountain in the snow ... and it didn't work."
"It's not GPS' fault. They're strictly a tool to travel by," Stokes said. "[They're] not any different from using a paper map. So take a paper map and your Garmin and use them both."