Interstate 10 / Interstate 110 Merge Restriping and Resigning

Client: Louisiana Department of Transportation and Development

You didn’t have to tell motorists in Baton Rouge that the Mississippi River Bridge was the only place along the entire length of I-10, from California to Florida, where the interstate narrowed down to just a single lane. They knew—especially if they were unfortunate enough to get stuck in the hour-long traffic jams that tied up the bridge several times a day.

The Nine Parish Regional Chamber of Commerce called it the number one transportation problem in the region. The issue: eastbound motorists coming off the bridge were forced to merge from two lanes to one, and then merge into traffic from I-110 South before proceeding eastbound on I-10. An estimated 80,000 cars and trucks cross the I-10 Mississippi River Bridge daily.

Widening the roadway was not in the cards—especially given the complexity of the job and the tens of millions of dollars it would costs. There were no funds available and little prospect that they would become available anytime soon.

Instead, the Louisiana Department of Transportation and Development called on ABMB to devise an effective short-term solution that would involve no construction. ABMB engineers fired up their modeling software and started to analyze the problem. Two months later, they delivered a solution for LDOTD and the Metropolitan Planning Organization to sign off on.

“People thought that the heart of problem was the Washington Street off-ramp at the end of the bridge,” remarked Mike Bruce, the partner in charge of the project. “They wanted to close it. One of the things the model revealed that closing the exit wouldn’t help at all. It was the merger of the two lanes was the problem.”

But ABMB did more than figure out what the problem was. They did something about it. They modeled a number of solutions and developed a restriping and resigning proposal that created two full lanes off the bridge. Signs were posted to make sure that eastbound traffic off the bridge headed toward New Orleans is in the left lane and Washington Street traffic is in the right lane.

The resulting operation matched that predicted in the study and resolved a major bottleneck for the I-10 cross-country route. ABMB has been subsequently retained to recommend long-term solutions at this location.

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