Abstract: A vehicle controller estimates the turbine torque based on measured impeller and turbine speeds. Then, it estimates the tractive force based on gear ratios, tire sizes, and estimates of parasitic losses. The controller estimates the current grade based on a difference between an acceleration sensor reading and the derivative of a measured vehicle speed. Then, it estimates the current vehicle weight based on the tractive force, the acceleration rate, and the grade. The controller adjust a target following distance of a cruise control system based on the estimate of the weight and the grade. The cruise control system adjusts power to maintain a measured following distance equal to the target following distance.