Michigan Truck Dispatch: Auto Freight, Detroit, Frost Laws

Michigan trucking runs on cars and Canada. The auto industry ships parts and finished vehicles between plants in Michigan, Ohio, Indiana and Ontario every day. Detroit is the busiest gateway for truck freight crossing from Canada. The Bureau of Transportation Statistics counted Detroit as the top port for Canadian freight in 2025, with 21.5% of truck traffic on the northern border.

The state's truck freight is close to balanced. About 95 million tons left Michigan by truck for other states in 2022, and about 98 million came in. About 25 million tons of Canadian imports entered through Michigan and kept moving by truck that year, more than through any other state.

The border: two Detroit bridges and Port Huron

For years, Detroit's truck traffic to and from Windsor, Ontario had one main route: the Ambassador Bridge. That changed when the Gordie Howe International Bridge opened to traffic on July 27, 2026. It gives trucks a second span between Detroit and Windsor with its own customs plazas. Port Huron, about an hour north, adds the Blue Water Bridge to Sarnia on I-94 and I-69.

• Cross-border loads need the right paperwork. Crossing into Canada takes carrier and driver credentials, and we book loads inside the lower 48 only. Your dispatcher books the domestic side: imports that clear at Detroit and move inland on U.S. trucks.
• Imports keep moving inland. Much of the freight crossing from Ontario is reloaded or relayed in the Detroit area for delivery across the Midwest and South. That creates domestic loads near the border.

What Michigan ships

Here are the biggest van, reefer and flatbed-type freight groups leaving Michigan origins by truck in 2022, from FAF6:

By tonnage, Michigan trucks deliver most to Ohio, Indiana, Illinois, Wisconsin and Texas, and receive most from the same states. That's the auto supply chain at work: parts move short distances between plants on tight schedules, often several times a week.

Michigan's freight areas

• Metro Detroit: auto assembly and parts, the border crossings, and distribution centers along I-94, I-75 and I-275.
• Grand Rapids and west Michigan: furniture and office products, food processing, and the fruit belt along Lake Michigan, with apples, cherries and blueberries.
• Lansing and Flint: auto plants and parts suppliers along I-69 and I-96.
• Northern Michigan and the Upper Peninsula: lumber, paper and seasonal freight, with long distances between loads.

Frost laws: Michigan's spring weight limits

Michigan cuts legal axle weights on many roads every spring while the frost comes out of the ground. In 2026, MDOT's first restriction took effect on February 17 in southern Michigan and the last ones lifted on May 15 in the Upper Peninsula. That's according to its spring weight restriction bulletins. On routes marked "seasonal" on the MDOT truck map, weights drop 25% on rigid pavement and 35% on flexible pavement. "All season" routes keep normal limits.

For a dispatcher, that means checking the route on every heavy load from late winter to spring. It matters most for flatbeds hauling steel or building materials. County roads post their own limits too.

Michigan freight by the numbers

Tonnage from the BTS Freight Analysis Framework (FAF6, base year 2022). Diesel tax from the IFTA, Inc. rate matrix.

Trailers that fit Michigan freight

A Detroit hotshot week on rush auto parts

Here's how a dispatcher might fill a week for a hotshot based near Detroit, where the auto supply chain pays for speed.

An example of how a week can be planned, not a promise of loads, rates or miles. Distances are rounded.

Expedited auto freight often comes with short notice and firm delivery times. Before accepting one, check that your hours cover it with our trip planner.

Michigan costs and rules

• Fuel tax. Michigan's diesel rate is 52.4 cents a gallon on the IFTA matrix for the 4th quarter of 2026. Our IFTA calculator uses it.
• Bridge tolls. The Ambassador Bridge, the Gordie Howe bridge, the Blue Water Bridge and the Mackinac Bridge all charge tolls by vehicle class.
• Winter. Lake-effect snow off Lake Michigan buries west Michigan and the U.P. Plan longer transit times from November to March.

Michigan checklist: frost laws, the border and bridge tolls

• From late winter to spring, check MDOT's weight restriction bulletins and the truck operator map on heavy loads.
• Confirm a load near Detroit is domestic. We don't book loads that cross into Canada.
• On expedited auto parts, check your hours and the plant's receiving window before you accept.
• Budget for bridge tolls on the Ambassador, Gordie Howe, Blue Water and Mackinac bridges.
• In west Michigan and the Upper Peninsula, add winter time for lake-effect snow.

Booking Michigan freight with us

Michigan freight follows the auto plants, and much of it is time-critical. Your dispatcher checks your hours against each plant's receiving window and, from late winter into spring, checks the frost law routes before booking anything heavy.

Michigan's busiest truck lanes run to and from Ohio and Indiana. Across Lake Michigan, see Wisconsin.