Selection of gear ratio based on a slope and load weight assessment

A vehicle comprising an automatic transmission and a set of sensor inputs that provide values ​​indicative of a current operational status of the vehicle and are relevant for the control of the automatic transmission. The set of sensor inputs comprising: engine speed, engine torque, current gear ratio; and vehicle speed. The vehicle includes a programmed processor, which is adapted to co-dependent and iteratively to produce a vehicle mass parameter value, and a slope degree parameter value. The programmed processor used when generating the vehicle mass parameter value and the slope degree parameter value, a set of parameters which include: a driving force that drives the vehicle; a set of forces acting on the vehicle and the forward movement resist, and an observed rate of change of speed of the vehicle.