A speed planning device is disclosed. The speed planning device may perform a method including obtaining elevation information associated with a route for a vehicle; identifying a section of the route based on the elevation information, wherein the section is associated with a change in elevation; determining subsections of the section; determining respective slopes of the subsections and respective lengths of the subsections; obtaining information identifying a mass associated with the vehicle; generating a speed plan for the vehicle to traverse the section, wherein the speed plan indicates one or more speeds at which the vehicle is to correspondingly traverse the subsections based on the respective slopes of the subsections, the respective lengths of the subsections, and the mass associated with the vehicle; and providing the speed plan to permit the vehicle to be controlled to traverse the section according to the one or more speeds of the speed plan.