The Alabama Department of Transportation (ALDOT) has begun construction on Jefferson County's first diverging diamond interchange (DDI) at Exit 104 on Interstate 20/59 and McAshan Drive in the town of McCalla, southeast of Birmingham, a $22 million project to accommodate rising traffic due to increased local economic development.
The interchange is located near the Jefferson Metropolitan Park (JeffMet McCalla), home to more than a dozen industrial campuses, including the $1.1B JM Smucker Uncrustables plant which opened late last year. Together, they contribute to the congested traffic at the busy interstate exit.
In addition, McAshan Drive offers access to the nearby Rock Mountain Lakes community.
Jefferson County Director of Roads and Transportation Chris Nicholson confirmed to WVTM-TV in Birmingham that the industrial park has led to a rise in truck traffic, particularly from the Smucker factory, and the number of vehicles on the road continues to grow, making navigation increasingly difficult through the corridor.
"We've seen spikes in residential developments in the southwestern portion of the county towards Tuscaloosa," he said. "So that in itself, and really that exit as a whole, has had some issues with left hand turns over the years. So, a diverging diamond really eliminates those conflict points."
The new design will transform McAshan Drive by redirecting traffic to resolve those issues, but it may also cause some confusion among commuters.
"You are definitely driving on the wrong side of the road, but it doesn't feel that way," Nicholson said, adding that the current stop signs will be replaced to allow for a smoother traffic flow without the need to cross traffic again.
ALDOT awarded the DDI building contract to Carcel & G. Construction in Hancel, Ala.
The project's funding was provided by three sources: Jefferson County kicked in $14 million, another $6 million came from a construction financing source within the Federal Highway Administration (FHWA), and $2 million was awarded by the Alabama Transportation Rehabilitation and Improvement Program-II (ATRIP-II).
Crews are currently building a new parallel bridge to handle the configuration while the existing overpass across I-59/20 will remain, according to ALDOT.
As motorists approach one side of the bridge, the DDI design allows traffic to gently transition from the right side to the left and then back again at the other end of the bridge. Drivers will make all left turns without crossing opposing traffic since it travels on the left side of the structure.
FHWA research shows DDIs are more cost effective, efficient and safe. Its data shows that construction costs can be up to 75 percent less, vehicle conflict points are often reduced by half and traffic efficiency increases of up to 30 percent have been observed.
New DDI First of Three in Area
The Jefferson County Economic and Industrial Development Authority (EIDA) has been advocating for similar roadway investments, which are expected to spur further development in the area, WVTM-TV noted.
"It will definitely help bring business to the area because … the number one thing [site selectors] look at is ingress and egress and closeness to the interstate and infrastructure," said Othell Phillips, executive director of the EIDA. "With the amount of property that we have available still left at JeffMet McCalla Industrial Park, it would be a huge asset for the recruitment process."
The multi-million-dollar road project is anticipated to be completed by April 2027 and is the first of three planned diverging diamonds in the greater Birmingham area. Others are slated for the Lakeshore exit on I-65 and the future Exit 9 on I-459.
Phillips emphasized the impact of these projects when he said, "For years and years, this agency has tried to make an impact and the biggest impact [is] to give people jobs and to create jobs. The deep foresight of the commission has been a huge help in us trying to achieve our goal."
During the I-20/59/McAshan Drive building project, ALDOT cautions motorists to expect temporary lane closures and traffic shifts.
