First of all, let me apologize for being a total math newb. I love geometry but I barely made it out of algebra alive...and that was 21 years ago. My girlfriend was recently involved in a car accident where she was charged with "Failure To Yield". Based on a spectacularly non-stellar, non-investigation by our local police department I have taken it upon myself to attempt to calculate the speed of the vehicle that stuck her (car) based upon the distance her car was moved during the accident. I'm aware that there are numerous variables that some of you are likely to want and I will do my best to supply them as requested/demanded. I'm unsure as to whether this is a problem to be solved with a velocity equation or a true speed equation with which I'm unaware. Vehicle A is a 2000 Volvo V70 station wagon. Weight is approximately 4,690 pounds. 5 gallons of unleaded fuel onboard at the time at 6.4lbs/gal = approx 32lbs. Driver weight is 115lbs. 150 lbs of horse feed was also onboard at the time. Total weight approx 4,987 lbs at the time of collision. Vehicle B is a 2000 Mitsubishi Gallant with 02 POB. Person 1 = approx 220 lbs; Person 2 = approx 120 lbs. Vehicle wt approx 3,270 lbs. Fuel/baggage unknown. Approx Wt subtotal with fuel unkown is 3,610 lbs. B impacted A slightly forward of the driver's door causing significant impact damage but very little rotational spin. Straight-line distance moved was approximately 48 feet before Vehicle A rotated approximately 35 degrees clockwise and came to a halt and Vehicle B rotated approximately 15 degrees counter-clockwise and travelled an additional 29 feet. How would I (you?) go about calculating speed of Vehicle B at time of impact. Speed of Vehicle B was less than 5mph at time of broadside collision (pulling out of a parking lot). There are numerous theories regarding why Vehicle B never applied the brakes before striking Vehicle A, but for now I'm attempting to stick with facts rather than hyperbole. I'm working on creating some diagrams to present to several people and if they would be helpful I can attempt to scan them in and upload them with this question. Again, thank you for any direction you may be able to provide.