How long does it take to form an opinion of speed

[Streetcop]

Seconds....IMHO

Street

[cuneus]

WRT

www.cumbriasafetycameras.org/forum/index.php?showtopic=626&st=45

[Ross_]

Fractions of a second

Ross

[zeroprobe]

sometimes i can misjudge if im not concerntrating.

Like on a 30mph road is someone is doing 70 odd and your expecting them doin 30 or 40.

at first you think to go and then ya take a second glance and figure out how much distance they hav covered........

[cuneus]

3 seconds is 60m at 46 mph (ACPO threshold)