HODGKINS, Ill. (WLS) -- The Illinois Tollway is about to start a massive bridge construction project along the Tri-State Tollway.The 61-year-old Mile Long Bridge, a stretch of I-294 between 75th Street and La Grange Road, carries 150,000 vehicles a day and is showing its age."People may have noticed we have been out there pretty regularly, patching and repairing this bridge. It no longer makes sense for us to keep investing dollars and maintenance and disturbing the motoring public," Illinois Tollway Chief Engineer Officer Paul Kovacs said.As part of the Central Tri-State Tollway widening project, a new Mile Long Bridge will be built just east of the current structure. Here's how it will work.Crews will first build the northbound bridge from La Grange to 75th. Traffic will stay on the current bridge during this time.When the new northbound bridge is complete at the end of 2020, they'll move traffic to the new northbound structure, keep southbound traffic on the southbound bridge, remove the old northbound bridge and build the new southbound structure in its place.When the new southbound bridge is complete, traffic will switch over and the old structure will be taken down.In order to make room for the new bridge, a couple of buildings have to come down, like a UPS facility in south suburban Hodgkins that has already been demolished. However, the Illinois Tollway is paying to relocate and rebuild.This project requires extensive coordination, as the bridges cross over two railroads, three waterways, businesses and local roads. The benefits include minimal traffic disruption, and a safer environment for both drivers and workers. The entire project goes through 2023.When the new Mile Long Bridge opens, it will have increased to five lanes in each direction, with a wider shoulder to be used as a flex lane.Engineers say the bridges will last longer, as they'll have fewer bridge joints, which are the first elements to need repair due to stress from the high volume of traffic.