Autonomous outdoor navigation requires the ability to discriminate among different types of terrain. A non-trivial problem is to manage the robot’s speed based on terrain roughness. This paper presents a speed control system for a robotic platform traveling over natural terrain. This system is based on the view of a line-scanning laser of the area just in front of the platform. Analysis of range data for roughness produced by the laser over different terrains is examined. An algorithm for managing speed through different terrain has been tested on real outdoor surfaces producing excellent performance.