Michigan § 257.631 - Public bridge, causeway, or viaduct; maximum speed, load, or gross weight; violation as civil infraction; assessment of civil fine; exceptions; determination of civil fine; determination of gross weight; investigation; signs; evidence.

A person shall not drive a vehicle upon a public bridge, causeway, or viaduct at a speed or with a load which is greater than the maximum speed or load which can be maintained with safety to the structure, when the structure is signposted as provided in this section. A person who violates this subsection is responsible for a civil infraction.

A person who drives or moves a vehicle or combination of vehicles, or the owner or lessee of a vehicle who causes or allows such a vehicle or combination of vehicles to be loaded and driven or moved, upon a public bridge, causeway, or viaduct when the gross weight of the vehicle or combination of vehicles exceeds the limitations established and signposted pursuant to this section is responsible for a civil infraction and shall be assessed a civil fine as set forth in this subsection. This subsection shall not apply to either of the following:

implements of husbandry operated upon a public bridge, causeway, or viaduct.

The use of a public bridge, causeway, or viaduct by a vehicle or combination of vehicles for a function essential to a farm operation otherwise reasonably inaccessible to vehicles performing the essential agricultural function.

The civil fine assessed under subsection (2) shall be determined as follows:

In the amount equal to 4 cents per pound for each pound of excess load when the excess is more than 2,500 pounds but not more than 3,000 pounds.

In the amount equal to 6 cents per pound for each pound of excess load when the excess is more than 3,000 pounds but not more than 4,000 pounds.

In the amount equal to 8 cents per pound for each pound of excess load when the excess is more than 4,000 pounds but not more than 5,000 pounds.

In the amount equal to 10 cents per pound for each pound of excess load when the excess is more than 5,000 pounds.

For the purpose of this section, the gross weight of a vehicle or combination of vehicles shall be determined as prescribed in section 722(7).

The department of transportation, county road commission, or other authority having jurisdiction of a public bridge, causeway, or viaduct may conduct an investigation of that bridge, causeway, or viaduct. If it is found after investigation that the structure cannot with safety to itself withstand vehicles traveling at the speed or carrying a load otherwise permissible under this chapter, the department, commission, or other authority shall determine and declare the maximum speed of vehicles or load which the structure can withstand, and shall cause or permit suitable signs stating that maximum speed and load limitations to be erected and maintained not more than 50 feet from each end of the structure, and also at a suitable distance from each end of the bridge to enable vehicles to take a different route.

The findings and determination of the department of transportation, county road commission, or other local authority, shall be conclusive evidence of the maximum speed and load which can with safety be maintained on a public bridge, causeway, or viaduct.