In case you are going to be hauling hazardous materials on an unfamiliar route, when should you check the route and the required permission for the trip?

Some states and counties require permits to transport hazardous materials or wastes. They may limit the routes you can use. Local rules about routes and permits change often. It is your job as driver to find out if you need permits or must use special routes. Make sure you have all needed papers before starting. [California Commercial Driver Handbook]