Dufferin Construction was recently awarded the $112.8 million job, said Liane Fisher, spokesperson for the Ontario Ministry of Transportation.

Advance work for the widening started last year, when the Speedsville Road bridge was replaced with a longer span, and repairs were made to the Highway 8 bridge over Highway 401. In May, the Fountain Street North bridge was demolished. Construction of a longer replacement bridge is expected to be done by November.

That three-bridge contract costs $18.9 million.

Monday, work starts on the main widening project along the 401, which is expected to take four years.

The first job will be repairs to the southbound Hespeler Road bridge over the 401. Lane closures are planned daily 9 a.m. to 3 p.m., until Oct. 30.

Also starting this year is widening work at the CN Railway and Speed River bridges, and construction of new outer lanes along the highway.

Over the following three years, traffic will shift in stages to the new asphalt so existing lanes can be rebuilt.

Other work is under study or planned for Highway 8 and Highway 401 from Kitchener, through Cambridge eastward to Milton, but work has not been scheduled, Fisher said. It includes:

• Widening Highway 401 between Hespeler Road to Townline Road, including new bridges at Hespeler Road and Franklin Boulevard; detailed design underway

• Widening Highway 401 between Townline Road to Halton Region boundary; preliminary design completed in June 2014

• Reconfigure Highway 8 and Highway 401 interchange with extra lanes and ramps to westbound 401; preliminary design completed in March 2010

In Milton and Mississauga, preliminary work to widen the 401 to 12 lanes (with collector lanes) is underway, with bridge replacements underway. Last year, widening of the 401 was complete as far west as the interchange at Highway 410.