Control of an autonomous vehicle

Control system having computer, processor, and memory, determines presence of precipitation / rain (e.g. using RADAR / LIDAR / sonar / camera), identifies an attribute of said precipitation (e.g. precipitation type / rate of rainfall / amount of rain), and determines an autonomous control action in dependence on the detection of rain (e.g. establishing vehicle speed / stopping distance / braking distance / rate of acceleration). Data may be collected by on-board sensors, or via remote server. A coefficient of friction may be calculated based on the detected precipitation attribute. Autonomous control action may also depend on type of roadway being traversed, or route topography. Claims are also included for a computer readable medium and a method of use.