CHICAGO (CBS) — Crews have finished two years of construction to build new ramps connecting the Stevenson Expressway and Lake Shore Drive.

The Illinois Department of Transportation said it has completed the $135 million project to renovate six elevated bridges linking I-55 and Lake Shore Drive near McCormick Place, and creating another entirely new ramp.

The project was designed to improve traffic flow, by widening the ramps to two lanes, instead of one. Officials estimated 125,000 vehicles use the interchange every day.

“It’s a vital gateway to Soldier Field, to the Museum Campus, and to countless events at McCormick Place,” IDOT Secretary Randy Blankenhorn said.

McCormick Place General Manager David Causton said he was “extremely pleased” the project is completed, as it should reduce traffic congestion in and out of the massive convention center.

The interchange project also included construction of six new retaining walls, installed new curbs and gutters, modified the drainage structure, relocated light poles and signs, and added surveillance equipment.

“I-55 and Lake Shore Drive is clearly an asset, yet the infrastructure that supported it was failing and aging. Prior to this project, this location was prone to frequent emergency backups, repairs, and unplanned work,” Blankenhorn said.

Chicago Department of Transportation First Deputy Commissioner Tom Carney said the completion of this project on time and $1 million under budget is a wonderful holiday gift.

“LSD is one of the most important pieces in the city’s transportation network,” he said.

During construction, workers uncovered charred debris from the Great Chicago Fire of 1871.