Michigan Truck Bans & Hazmat Routes

Where Michigan keeps trucks out

Detroit's crossings are the story. The Detroit-Windsor Tunnel bans all placarded hazmat and posts a hard ceiling near 12'8" that many box trucks clear only on paper. The Ambassador Bridge reopened to most hazmat on October 29, 2024, so Class 3 flammables and Class 8 corrosives now cross off-peak under escort. Explosives, infectious and radioactive loads take the Gordie Howe International Bridge, open since July 27, 2026 and built for all nine classes of dangerous goods with no specific permit or notification; the Detroit-Windsor Truck Ferry made its final crossing September 29, 2023. No cars-only parkways; through trucks take the I-696 and I-275 beltways.

Key restrictions

• Detroit-Windsor Tunnel: no placarded hazmat at all, and a hard height limit near 12'8" that many box trucks and reefers do not clear.
• Ambassador Bridge now takes Class 3 flammables and Class 8 corrosives off-peak under escort (since Oct 29, 2024); it still bars Class 1 explosives, Class 6.2 infectious, and Class 7 radioactive.
• Blue Water Bridge (Port Huron) bars classes 1, 5, 7, 9 and pyrophoric liquids; Class 1 and 7 loads bound for Canada cross on the Gordie Howe International Bridge, open since July 27, 2026, which takes all nine classes with no specific permit or notification.
• No cars-only parkways; through trucks use the I-696 and I-275 beltways around Detroit.

• Parkway / road ban: No cars-only parkways. Detroit posts local truck routes and moves through trucks onto the I-696 and I-275 beltways.
• Hazmat: The Detroit-Windsor Tunnel bans all placarded hazmat and posts a roughly 12'8" height limit. The Ambassador Bridge reopened to most hazmat on October 29, 2024: Class 3 flammables and Class 8 corrosives now cross during off-peak hours under vehicle escort, and only Class 1 explosives, Class 6.2 infectious substances, and Class 7 radioactive material remain restricted. The Blue Water Bridge (I-94/I-69, Port Huron) bars classes 1, 5, 7, 9 and pyrophoric liquids. Loads the other crossings refuse take the Gordie Howe International Bridge, open since July 27, 2026 and built to carry all nine classes of dangerous goods with no specific permit or notification required. The Detroit-Windsor Truck Ferry made its final crossing September 29, 2023 and is no longer an option.
• Through-truck routes: Detroit and other cities mark truck routes and post weight limits on local streets. Through trucks use the I-696 and I-275 beltways around Detroit. Michigan sets hazmat routing through MDOT; a local truck may leave the route only for the nearest stop.
• Fine: A hazmat placard or over-height violation at a border crossing gets you turned back by the operator and CBP and can draw federal hazmat penalties; local truck-route and weight tickets in Detroit typically run about $100 to $500.

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