I have played around with a MINI GPS PA1010D STEMMA QT from Adafruit. While when stationary it will read under 1.0 MPH when moving it is pretty accurate. My Wife's truck is a cherry 99 Tahoe so we added a Garmin GPS and that thing is right on target for speed and everything else. I have my GPS module connected to an Arduino Uno Rev 3 and a 4 line 20 character display and you can choose what you want to display.
Ron