Depending on the year, make and model of your car and the other parties car, the ECM can be downloaded. It will typically provide vehicle speed at the time of collision and vehicle speed history for 5 or more seconds leading up to the collision. Your speed history should show you stopped and then accelerating prior to impact, consistent with your account. The other cars speed history would confirm your account of them not slowing before impact. The insurance company should have someone download the vehicles.