The speed limit in Cumming varies slightly across different roads and zones. If you are driving on Highway 400, you have to observe a speed limit of 65 mph. If you are driving within residential areas and school zones, you need to observe a speed limit of 30 mph. The city’s speed cameras erected on Knox Bridge Highway, Cumming Highway, and Highway 109 have helped the Cumming traffic police department to enforce the speed limit law more effectively. Search rental cars on KAYAK