Registered Forum User
Big Twin
Posts: 1,956
Join Date: Mar 2005
Location: Normally in my own little world
Mood: I own a flame thrower
thought they used the white marks on the road as a second check on speed etc. I thought they took 2 pic's and measured the change in vehicle position using the lines. That way then can also calculate your speed, knowing the distance covered in a set time between the 2 pic's being taken.