I was thinking we could all use seconds and decimal fractions thereof
Oh, I see what you mean.  Find a quietish straightish bit of road and take along a passenger with a stopwatch.
Not too scientific I know, but absent some fancy laser measurement device, it's my best suggestion.
Either that or you mark the point at which you start and then throw a tin of paint out of the window when you reach 60.  Then measure the distance between the two points.  You now have both distance and speed so you can calculate time.  That said, the tin of paint will be travelling at 60 mph when you throw it out the window, so you'd have to do some calculation based on the weight and aerodynamics of the tin of paint to account for that.
Best find a mate with a digital watch...
