I’ve tracked my GPS vs. speed limit accuracy. It’s not accurate.
Really?
I’ve used the MPH shown on my Garmin GPS verses the actual speedometer on the car.
The GPS is more accurate in acutal miles per hour.
YMMV.
I have a trip recording program on my cell phone. I can turn it on when I leave home and off when I get to work. I have tested it and it is damn accurate.
It will tell me the following:
1) Total time in motion.
2) Total time at rest.
3) Total combined time.
4) Top speed reached.
5) Average overall speed.
6) Continuous elevation changes above sea level.
7) It can map the trip so I know the exact route I took.
It is a free app on my phone and it can do all of this. I guarantee the gov has better stuff.