Speed record

Does anyone know the fastest speed obtained on a uni on flat land and self propeled?

thanx

30 MPH, on a coker, obtained by some guy.

I think that was down hill. I want to know the fastest on flat land, with out being pulled by a car

For what distance or time? Straight or oval course? Witnessed or self-claimed? Speedgun or not?
There’s lots of anecdotal stories out there, but it’s generally accepted that 25mph (40km/hr) has been done at least for a moment. The 100m standing start Guinness record of 12.11 equates to well over 20 at the finish line.