No the ecm does not store speed info. Post ur email or tx and we can talk. I am a technical accident investigator and can give u some advice. Braking distance is going 2 be dependant on the vehicle speed, coefficient of friction of the roadway, % of braking of each tire, roadway slope and elevation, and total weight. I can rough guess but for court ur going 2 need 2 conduct test skids on the actual road. Hit me up and i can help u out more. Brett