State to beef up busy south-side interchange

State highway officials are accepting public comments through today on the most recent design tweaks for a $45 million reconstruction of the busy interchange at interstates 65 and 465 south of Indianapolis.

The Indiana Department of Transportation will add another lane in both directions of I-65 between the interchange and Southport Road. More lanes also would be added to I-465, east of the interchange. And a single-lane ramp from northbound I-65 to eastbound I-465 would be widened to two lanes.

The latest changes keep in place the most dramatic feature unveiled earlier this year: a flyover ramp from westbound I-465 to southbound I-65. The flyover will replace a tight-radius loop ramp on the northwest corner of the interchange that causes traffic to creep onto I-65 South, particularly when semi trucks use it.

Many of the public comments received so far pertain not to the changes in traffic movements, said INDOT spokesman Will Wingfield.

“It’s been about noise,” he said.

So the latest design proposal contemplates additional noise walls, particularly south of the interchange on I-65. As a result, the cost of the project has risen to $45 million from $36 million projected earlier.

The updated plans leave in place a peculiar legacy design feature of the interchange: ramps that feed I-65 traffic into the high-speed left lanes of I-465. That occurs where southbound I-65 traffic enters eastbound I-465, and where northbound I-65 enters westbound I-465.

There was no need to alter those ramps because problems don’t occur at those points like they do at northbound I-65 to eastbound I-465, and the I-465 westbound to southbound I-65, Wingfield said. “Those are the ones that back up most frequently.”

About 110,000 vehicles per day travel on I-465 and 106,000 on I-65 in the vicinity of the interchange, according to INDOT records. That compares with about 125,500 vehicles on I-465 between Allisonville Road and Interstate 69/Binford Avenue on the northeast side of Indianapolis.

The I-65/I-465 interchange improvements will provide welcome new business potential for highway contractors, who will get a chance to bid in July of next year. Construction is to start later in 2013, with completion likely in late 2014.