Motorists are frustrated with the construction on the Hancock side of the bridge and are taking it out on the workers there.
Police Chief Wayne Butler says there have been reports of people throwing objects at the workers from car windows and shooting at them with pellet guns.
Drivers are also speeding through the construction zone and have damaged equipment.
When asked why police were not immediately called, Butler said the crews did not want to upset the community any further.
Roadwork by the Michigan Department of Transportation has been a staple in Hancock for the last two summers but the end is in sight.
City Manager Glenn Anderson said the majority of the work is expected to be completed by the end of next week.