GPS and One-Way Streets
Every couple of weeks I stumble upon an article on the web and I scratch my head. Truthfully, it happens more often than that, but it isn’t always about GPS. So here is my head scratcher for today. Yes, GPS devices do indeed differentiate between one way streets and two way streets. And so long as the map data matches the current physical world, they won’t route you the “wrong way” unless you are in pedestrian mode.
It turns out that GPS receivers and their mapping programs don’t know which streets are one-way and which are not. – James Foster, timestranscript
I’m hoping that he meant this in a sarcastic way, as people reading the article might get the impression that GPS devices in general do not know about one-way streets. Mapping errors do exist from time to time, but in my tens of thousands of miles of travel with GPS per year I’ve never had a GPS route me the wrong way on a one-way street. Click on the map on the right and you will see a screenshot from a GPS device which clearly marks the one way streets.
James goes on to say this:
The best part of a GPS is that, as long as you have sufficient batteries to power the machine, no matter where the GPS leads you, it will always show you the way back, no matter what. I say again: As long as you have spare batteries.
This almost makes me wonder if he was using a handheld GPS device that likely wouldn’t have included detailed auto routing maps. Every auto GPS on the market today I can think of comes with a car power adapter so you don’t need to rely on the battery power. In fact, the vast majority of them don’t come with replaceable batteries instead using batteries that are permanently sealed inside the device.
Again, I hope the article was written with sarcasm in mind, but it is points like those about GPS that leave me spending so much time trying to debunk myths.






I wouldn’t doubt that driving the backroads of New Brunswick would leave him with a bad impression of his GPS. It seems that a lot of the non-major roads away from towns are only listed as an unname road, even in Garmin’s City Navigator 2008/9. And what they call roads can at times turn into access roads for hunters in 4X4’s, no place a tourist really wants to end up.
I’m just glad he didn’t have a TomTom and visit St. Andrews, New Brunswick. According to Tele Atlas, this 200+ year old tourist town doesn’t have any roads.
Yes, indeed– St. Andrews, NB looks really bad on the Tele Atlas map.
Tim, that makes me think. Should whether the battery is replaceable or not be listed in future reviews? It was never really important to me before but now that I have a unit with one I find it is something that I would consider in the future. I’d also like to see the routing mode options listed, ie; easy, fastest, shortest, pedestrian, bicycle, etc.
All of those will be added to our product database in the future.
With billions of miles of streets, some that are not fully one way or two it is possible. My home address street is one way west and my Garmin Nuvi 200 tries to have me go east on it. I live in a small rural town but it is the county seat and relatively big. So far it is the only wrong way any of my units have tried to navigate me on. Not a bad record in my opinion. I just wish I could teach it somehow.
Ralp, many GPS devices like those that have TomTom MapShare will allow you to teach the device about mapping errors as well as share those changes with other users.