I had a Volvo XC90 that “jumped” off the interstate and onto a parallel mountain road east of Knoxville. It did its best to track along those roads and somehow made its way into North Carolina. But even when I was back in Chicago, it was still stuck in NC trying to find a way off those mountain roads. Dozens of on/off cycles did nothing. I disconnected the battery overnight and that didn’t work. At the next service appointment, the dealer had to do a full firmware reset to wipe the memory and get it working again.

It amazed me that Volvo programmed an SUV to disbelieve that it could ever actually leave a road.

Last summer traveling down a rural road in southwestern Ontario, Apple maps told me to return to the route. We hadn't turned in 10 kilometers, but it was showing that we were 200 meters into a cornfield.

I don't think I could have ended up there if I tried in the Golf we were in. Nice try.

My kids thought it was the funniest thing, but it's a good technology lesson.

In Boston it's a very frequent occurrence to be driving in the Central Artery Tunnel and have your map software think you're on the surface, or vice versa, or to be on a highway overpass and again have it think you're on a surface road that is inaccessible from your location. You get used to it.

This seems like an entirely different level of craziness, though.

The problem is that roads are continually being built and maps aren’t always as quick to be updated.

There are also private paths that aren’t public roads but are still intended for vehicles.

A badly programmed Kalman filter perhaps

> It amazed me that Volvo programmed an SUV to disbelieve that it could ever actually leave a road.

Only for footpaths in residential areas.

I wonder what class of vehicles is least likely to go off roading?

My dad used to have a crappy aftermarket GPS in his car that did the same thing. It would get lost dozens of miles away, and then hundreds of miles away.

The explanation I found online at the time was that a GPS receiver needs to download data about the exact orbits of all GPS satellites from time to time. Satellites slowly lose altitude and change their orbits. Up-to-date information is constantly broadcasted by every satellite, but it takes about 15 minutes for a device on the ground to download this dataset.

Most GPS devices do this automatically whenever they get the chance. But if your GPS is somehow unable to stay online for 15 consecutive minutes (bad firmware, faulty memory, tunnels, underground parking lots, etc), it will be relying on increasingly outdated info and drift far off its actual location.