In this study, a speed vector is defined for static trajectories for mobile robots. In many conventional path-planning methods, the major criterion is to plan the trajectory through obstacle-free regions to satisfy safety. The obstacle configuration is not the main concern for controlling the speed of the mobile robot. This issue is handled as a sub-procedure under path tracking scheme rather than a standalone operation. Thus, it is performed that planning a speed vector within the planned static trajectory. Directory lines are fitted on consecutive path coordinates to check whether an obstacle is available on the motion direction of the mobile robot or not. This procedure is operated continuously to control the instant average speed of the mobile robot.