When driving a placarded hazmat vehicle, you must:

Many states and municipalities restrict the routes hazmat vehicles may use, especially in densely populated areas, near tunnels and bridges, and through environmentally sensitive zones. The driver is responsible for knowing and following these restrictions. Tunnels are often prohibited or restricted (Class 1 explosives commonly banned, others requiring special permits) because a fire in a confined tunnel is catastrophic. Population centers, downtown business districts, and certain residential areas may also be restricted. Federal law also requires routing to avoid heavily populated areas, narrow streets, and other unsafe roads when alternative routes exist. Some materials (Class 7 radioactive in highway route controlled quantities, for example) require permits specifying the exact route.