Maine Truck Bans & Hazmat Routes

Where Maine keeps trucks out

Maine has no cars-only parkway. Portland is the metro that matters, and the city posts an over-dimensional truck and bridge-restriction map you should follow downtown. I-295 through Portland has posted structures and active bridge work, so check current limits. Maine runs a 100,000 lb six-axle rig on its Interstates under a permanent federal exemption. No state tunnel bans hazmat; follow the Interstate and posted routes under 49 CFR 397.

Key restrictions

• Any Maine bridge under 14 ft 6 in of clearance must be signed and any bridge that cannot take a legal load is weight posted (29-A M.R.S. §2380, §2387); read the plate, and do not assume a railroad overpass is signed.
• I-295 through Portland has posted structures and active bridge work; check current limits.
• Maine allows a 100,000 lb six-axle rig on its Interstates under a permanent federal exemption (23 U.S.C. §127; 29-A M.R.S. §2355-A).
• Obey posted bridge plates; a car GPS will not carry them.

• Parkway / road ban: No cars-only parkway. Portland is the main metro. Risk is posted weight-restricted and low bridges, not a truck-ban corridor. Portland publishes an over-dimensional truck routing and bridge-restriction map.
• Hazmat: No state tunnel hazmat ban. Placarded loads default to the Interstate and Maine Turnpike and follow state-designated or preferred routes under 49 CFR 397 and the FMCSA registry.
• Through-truck routes: Maine posts its structures. Any bridge giving less than 14 ft 6 in of clearance has to carry a clearance sign, installed by whoever owns the road, and railroad overpasses on town ways are the ones most often missing it (29-A M.R.S. §2380). A bridge that cannot carry a legally loaded vehicle gets a weight posting (§2387). Towns post their own truck routes and weight limits on top of that; a through truck stays on the state and Interstate network and a local delivery takes the direct path to its stop.
• Fine: Overweight and posted-bridge violations run on MaineDOT and state penalty schedules, scaling with the overage. Confirm the current figure with the Maine DOT or Bureau of Motor Vehicles.

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