I-65 Lakeshore exit potential site for state’s first Diverging Diamond

Drivers who use the Lakeshore Drive exit on I-65 know what a headache it can be.

The heavy conflict from weaving movements, long cycles and multiple left turns required to access the interstate from Lakeshore have been on the City of Homewood’s radar since 2000. But within the next two years, the landscape at the exit could look drastically different.

During its regular meeting in January, the Homewood City Council approved for Mayor Scott McBrayer to enter into an engineering contract with Volkert, Inc. The agreement would seek to address congestion issues on Lakeshore Drive between Green Springs Highway and the Homewood Commons retail district by implementing inventive methods of traffic flow. 

Volkert’s 2013 proposal, selected by McBrayer among competing submissions to the City, is to install a Diverging Diamond Interchange at the site.

The Diverging Diamond is a novelty of road engineering that is being constructed at interstate exits across the country. Perhaps most recognizable for Homewood residents would be the I-285 interchange with Ashford-Dunwoody Road in Atlanta near Perimeter Mall. If installed at Lakeshore, Homewood would be the first community in the state to employ the technology.

A Diverging Diamond crosses traffic to the opposite side of the road at the bridge, which creates an opportunity for drivers to veer left onto the interstate without stopping. It also allows vehicles approaching Lakeshore from I-65 off ramps to merge into traffic instead of waiting for a light.

Imagine driving from Colonial Brookwood Village to Wildwood. As you approach the I-65 interchange, you’ll be directed into the left lanes of the bridge, and opposing traffic will be on the right side of your vehicle. At the end of the bridge, you’ll be directed back into the lanes you were in when approaching the interchange.

As of Feb. 10, Homewood and Volkert had not yet entered into an agreement. But, to learn more about the Diverging Diamond, The Homewood Star contacted Volkert, Inc. and discussed possibilities for the interchange with Project Manager Rob Vermillion.

Vermillion said Diverging Diamond Interchanges have received warm welcomes in Missouri. According to divergingdiamond.com, a Missouri Department of Transportation survey reports that 97 percent of drivers feel safer at the interchanges, and collisions were reduced by 60 percent over a five-month window of study.

In Versailles, France, a Diverging Diamond has seen only 11 light crashes in five years, the site reports.

Vermillion said Volkert recently completed design of Mississippi’s first Diverging Diamond. It is under construction now. The company’s experience with the design, meshed with the favorable geographic conditions at the Lakeshore exit, led it to propose Alabama’s first installation.

“The Diverging Diamond lays out perfectly for that interchange,” Vermillion said. “There would be almost no need for grading, and the existing bridge appears to be wide enough to accommodate the design.”  

To install the Diamond, Volkert proposed to create access to I-65 Southbound on the south side of Lakeshore in the current right-of-way. The on-ramp would travel alongside the Sam’s Club property. The company also proposed to eliminate use of the circular access to I-65 south on the north side of the bridge, instead drawing straight-line access to Lakeshore for drivers exiting from southbound lanes.

The straight-line access is important to the design. The most perilous point of the intersection occurs where drivers exiting I-65 south must merge across moving traffic to access the left turn lanes into Walmart. Average annual daily traffic counts, referenced from the Alabama Department of Transportation (ALDOT), for that short distance are approximately double what they are at other points of the intersection. Approximately 52,000 vehicles travel it each day, as opposed to 27,000 that cross the bridge.

According to Homewood Chief of Staff J.J. Bischoff, vehicles attempting to use those turn lanes frequently causes traffic to slow. He said Homewood’s initial idea to ease congestion was to line up the I-65 Southbound off-ramp to Lakeshore with the entrance to Walmart.

“ALDOT shot that down,” Bischoff said, noting the Department was bound by the Federal Highway Administration’s (FHWA’s) use of public funds to acquire rights-of-way when Walmart and Sam’s Club were constructed.

ALDOT Third Division Engineer Brian Davis said modifications to the interchange would need FHWA approval. However, he also said west of the Greensprings Highway intersection is where Lakeshore Drive — Alabama Highway 149 — turns to Lakeshore Parkway, which is no longer a state road. Davis said if necessary, Homewood would look toward Jefferson County for any financial assistance on the project.

“We have to approve anything that’s done, but what we’re interested in is the interstate,” Davis said. “We chime in when how people get people on and off starts to have a negative impact.”

Vermillion said a Diverging Diamond could likely be installed at Lakeshore without the acquisition of new right-of-way property. Volkert’s proposal to Homewood indicated that installing a Diverging Diamond at Lakeshore would cost approximately $3.5 million, assuming no bridge modifications were required. He added that the project could require as little as two years to complete. 

Included in the study phase timeline are approximately 6 to 9 months for obtaining traffic counts, conducting a corridor study and interchange modification study and obtaining the appropriate reviews. Any issues with roadway capacity will be verified by this initial traffic study, Vermillion said. This phase would be followed by another 12 to 15 months of design, followed by construction.

Volkert is currently contracted with ALDOT on the connection of I-65 to I-22. Work can be seen in the Fultondale area. The project, when complete, would provide a direct connection between Birmingham and Memphis.

In addition, Volkert has been contracted by ALDOT to replace the I-20/I-59 bridges through Birmingham.