I've been looking at these for a while:
http://www.escortstore.com/gtimer.htm
I'm fascinated by electronic gadgets and a couple guys ran with them during Autocross events for the G-Meter function. I finally gave in and picked one up.
They claim to be "amazingly accurate" and are used by auto makers, race teams, and car testers such as Car & Driver ( ).
I ran up and down a fairly level stretch of back county road a few times to see what the G-Timer's 0-60 times came out for the MM. I read enough of the manual to figure out how the "Timed Run" mode works: Press the "Start" button (it waits for the car to start moving) and then accelerate until you get about 5 miles above the maximum speed you want to measure.
It displays the max speed of each run and seemed accurate by my eye. There's all kinds of neat things this will measure. Acceleration time, HP, 60-0 mph braking distance, 1/4 & 1/8 mile time, and directional g's. Neat toy!
- JD