VOL. 128 | NO. 206 | Tuesday, October 22, 2013
Reconfigured Interchange To Improve Traffic Flow
By Ian Engstrom
Phase II of substantial improvements are about to begin on the Interstate 40/240 interchange in East Memphis that will address the expected traffic increase in this area for decades to come. The average daily traffic (ADT) on I-40 has grown from 49,000 vehicles in 1985 to about 200,000 vehicles a day in 2013. By 2035, projections show the interchange could be handling well over 350,000 vehicles.
The interchange is formed by I-40 on the north and east legs, I-240 on the south and Sam Cooper Boulevard on the west. The existing interchange is unique in its current configuration as I-40 is reduced to one lane in each direction. Adding to this problem are the low speed exit ramp movements, which are not conducive for good interstate flow. Phase II improvements to the I-40/I-240 interchange will improve the flow of traffic.
The project will encompass Sam Cooper Boulevard to the White Station overpass, I-40 from Sycamore View to Covington Pike including the complete replacement of the bridge over the Wolf River, and I-240 to the north side of the Walnut Grove interchange. The existing low speed ramps, which carry the eastbound and westbound I-40 movements, will be replaced by higher speed flyover structures with two lanes each. Interstate 40, I-240 and Sam Cooper Boulevard will be widened with an additional lane in each direction within the limits of the project. This construction will improve traffic capacity and efficiency. The final interchange configuration will include four levels, the first of its kind in West Tennessee. Once completed, the fourth level structure will rise a towering 75 feet above Sam Cooper Boulevard.
This is a critical interchange for this region, prompting state Transportation Commissioner John Schroer to issue a directive to get the job done quickly. To manage the construction of this project, TDOT hired Smith, Seckman, Reid Inc. (SSR), a full-service engineering company with a long history of providing construction oversight on projects in this region. Jackson, Tenn.-based Dement Construction Company LLC submitted the lowest bid and was awarded the contract to construct the job in three-and-a-half-years. The award of $109.3 million is the largest single contract ever let by TDOT.
Although substantial improvements and upgrades are ahead for the interchange, our team is mindful that any kind of interstate construction will be disruptive to traffic flow. We have worked hard to minimize the impacts by shortening construction zones within sections of the project and proposing an aggressive construction schedule that will pay an incentive to the contractor for finishing early. The shortened construction zones should limit the length of barrier-lined interstate highway to about one mile through any part of the interchange at any one time. Phase II is scheduled to be finished by the summer of 2017. However, with an incentive for an early completion it could be completed by the end of 2016. We know there will be delays, including traffic congestion during peak hours and temporary lane closures during off-peak hours. Phasing this construction to minimize the impact to motorists has been challenging, however we have a good plan and expect to significantly reduce the impact to Memphis area travelers. When the interchange is completed in a little over three years, motorists will be able to navigate a reconfigured interchange with much-needed safety upgrades, improved infrastructure and efficiency.
Until construction is completed, drivers are advised to be alert and follow the posted directions in work zones. Smartphone users can download TDOT’s SmartWay Mobile App to assist in navigating Tennessee highways and the construction in this area with up-to-the-minute customized traffic information. Users have access to TDOT’s cameras and important messages on overhead dynamic message signs. Download it free from the Apple App Store or the Android Play Store. These apps are great tools to use for checking travel conditions before motorists leave for their destination.
The team formed by the partnership of TDOT, Dement Construction and SSR is confident the job will be a great success in providing Memphis and surrounding region with the excellent transportation system that the people of Tennessee have come to expect.
Ian Engstrom is a senior bridge engineer/project manager at Smith Seckman Reid Inc. in Memphis.