I-20/59 downtown viaduct
The I-59/20 downtown viaduct is an elevated section of Interstate 59/20 running east to west through downtown Birmingham from "Malfunction Junction" to 31st Street North. The 1.3 mile section was completed in 1971.
The downtown viaduct was designed to carry 80,000 cars per day. It was originally planned to be built over mounds of fill dirt brought downtown from the Red Mountain cut, but civic leaders eventually pushed for it to be left open underneath for parking. The Alabama Department of Transportation instructed the city that any changes made to its design, and the cost of any delays, would have to be paid for by the city.
In June 1964 the Downtown Improvement Association and Downtown Action Committee joined with the Birmingham City Council in passing resolutions asking Mayor Albert Boutwell to commission a feasibility and cost study for providing space for automobile parking underneath the four block area between 18th and 22nd Street adjoining the Civic Center and also under parts of the Red Mountain Expressway between 2nd and 6th Avenues North near the Birmingham Post Office. At the time it was anticipated that it would be possible to build a two-level parking structure below the interstates, providing as many as 1,360 spaces.
In the 2000s the Department of Transportation proposed a bridge deck replacement project. That proposal was expanded into a viaduct replacement plan, with new, wider bridge decks spanning farther between larger, higher support posts. That scheme eliminates all left-lane exits and most other downtown access roads and proposes using pre-cast concrete deck sections rather than steel beams to reduce road noise.