Dozens of road reconstruction projects across Michigan came to a standstill Tuesday amid a contractors' lockout of hundreds of unionized heavy equipment operators and technicians.

The lockout of the construction sites was called by the Michigan Infrastructure & Transportation Association, which represents contracting firms that build roads, bridges, sewers and utility systems. The union members who are locked out are with Operating Engineers Local 324.

There was no indication Tuesday about when the lockout might end.

The contractors "are doing a defensive lockout in reaction to coercive and disruptive tactics that the union has been engaging in all summer long," said Michael Nystrom, the association's executive vice president. "Work will continue on some construction projects across the state, and may be halted on others."

The number of road projects affected wasn't available Tuesday morning, but includes the Interstate 75 River Rouge Bridge repairs, I-696 reconstruction and the M-59 project, said Dan McKernan, spokesman for Local 324, which represents the equipment operators, mechanics and technicians.

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The union has no idea how long the roughly 40 contractors will continue their lockout.

"How can they shut down road work when there is so much to do?" McKernan asked. "All summer they’ve professed that nothing is more important to them than their employees, then they go and lay them all off."

The five-year contract between the Michigan Infrastructure & Transportation Association, known as MITA, and Local 324 expired June 1. The association has been bargaining labor agreements with the union on behalf of contractors for decades.

Since the contract expired, the union has refused to negotiate anymore with the association, which it has accused of anti-labor positions.

Instead, the union has tried to negotiate directly with individual contracting firms that the association represents. The union claims it succeeded in getting some contractors to sign a new master agreement, although it won't disclose how many.

"We are trying to get MITA out of being the middleman with the operating engineers," McKernan said.

But Tuesday's lockout suggests that the union's effort to cut out MITA has so far been unsuccessful.

"We are not aware of any in-state contractors who have signed that thing," said Nystrom, the MITA executive vice president.

From the association's standpoint, the lockout will continue until the union agrees to once again negotiate with the association.

Nystrom said that according to the association's interpretation of state laws, and contrary to what the union is telling members, the locked-out workers are not eligible for state unemployment benefits.

"We've negotiated for over 80 years with numerous other unions, and I think that they (Local 324) felt that they could self-author a contract and force contractors to sign it — and they are finding out otherwise."

From the union's perspective, a key reason for not negotiating with MITA was the association's insistence that contractors don't have to pay union-level benefits, such as health care, to nonunion subcontractors.

For Local 324, continuing to allow that practice would give contractors too much of a financial incentive to avoid union labor in the future. The issue became even more critical after the Republican-led Michigan Legislature in June repealed the state's prevailing wage law, which required union-scale wages on public construction projects.

McKernan acknowledges that the union did not accept a contract proposal this summer from MITA that would have given its members average annual pay increases of 1.6 percent to 3.6 percent over five years.

“Our point has been all along that it doesn’t matter what you offer in wages if the work isn’t going to be there," McKernan said.

The association has accused the union of various disruptive tactics, including coercing workers away from contractors and refusing to provide additional employees for contractors.

Specifically, it claims Local 324 two weeks ago disrupted a paving work site on I-96 in Detroit, picketing and stopping work there for about three hours. (The union claims it was merely an "informational picket" that didn't force work to stop.)

Contact JC Reindl: 313-222-6631 or jcreindl@freepress.com. Follow him on Twitter @JCReindl