Vehicle speeding is one of the major reasons lead to highway traffic accidents

velocity measurement range of traditional fixed camera video velocity measurement system is very limited. Driving state of the front vehicle is obtained by using the vehicle mounted binocular charge coupled device（CCD） camera

and a method for measuring the speed of the front vehicle is proposed.The proposed method uses the improved Hough transform to identify the lane lines and extract the region of interest

complete the vehicle detection on the basis of characteristic of vehicle shadow

the relative displacement of the vehicle and the corresponding time interval are obtained by selecting the appropriate image frame in the vehicle video image

and the driving speed of the front vehicle can be calculated.The above algorithm is tested

and high precision of the speed measurement results can be obtained.