I’ll give it a shot on my commute tomorrow and let you know what happens when you ignore its routing instructions. I believe that it would show you on the breadcrumb map where you are vs. where you’re supposed to be, but wouldn’t give you specific cues/directions as to where you should turn next (since it only knows the route that was loaded and your GPS coordinates).
Results of this morning’s test: when still paired with my phone and the app running in the background, my GPS displayed re-routed directions within about half a block. When not actively paired with my phone, the GPS displayed a breadcrumb map showing how far off course I was and directed me to turn around, but rejoined the directions when I got back on route at a later point (I only went a block out of its way). All in all – not bad.
I am quick to recommend the Garmin Oregon series, but they really are not for everyone. They are heavy and big and require some time to set up the maps. https://buy.garmin.com/en-US/US/p/550460
The newest series, are fully ANT, wifi, and bluetooth connectable so all the modern H.R. monitors, speed sensors, cadence sensors, etc.. will connect. https://www.thisisant.com/directory/oregon-700
The batteries are just AA, I use 2400mAh rechargeables and they last for 10 hours, plus I can pause the machine and change out batteries mid-ride. The map set up it not too hard, I use Open Street Maps, the same maps used in Strava, and am very happy with them. Plus I can update them anytime and load up maps for any part of the Globe. I use this OSM generator to prepare my maps. http://garmin.openstreetmap.nl/
.
