1. A method for reducing speed error in determining the speed of a motor vehicle in a vehicle speed detection system, the method comprising: receiving a plurality of infrared images of a motor vehicle traveling on a road, each of said images being separated in time by a known interval, said infrared images having been captured using a single camera infrared imaging system operating in an infrared wavelength band spectrum range specifically selected such that a contrast of a point of contact between the tires of said vehicle and the road surface is optimized with respect to road material and tire rubber in said images, said infrared imaging system positioned adjacent the road; determining, for each of at least two of said images, the point of contact where a same tire of said vehicle contacts said road surface, such that a height of each point of contact is zero; mapping said points of contact to a (x,y) two dimensional coordinate system, such that each point of contact has a (x,y) set of coordinates; using said coordinates and said time interval separations to calculate a speed at which said vehicle is traveling on said road; and communicating said vehicle's speed to a computer system; for comparing said vehicle's speed to a speed limit established for said road.