We are excited to announce the acquisition of Vision Engineering & Planning, a transportation planning and engineering DBE firm with offices in Columbia, MD and Atlanta, GA.
By: Erin Curry, P.E., R.S.P.
Did you know the state departments of transportation oversee all construction and maintenance of our Interstate System, but the federal government maintains oversight to interstate access? Therefore, any change of access to the Interstate System requires approval by the Federal Highway Administration (FHWA). I recently attended an FHWA workshop at the Tennessee Department of Transportation (TDOT) Region 3 office on Interstate Access Requests (IAR).
We have prepared numerous IARs over the years for TDOT, including the soon-to-be reconstructed Exit 46, I-65 at Bear Creek Pike, Interchange in Maury County and recently reconstructed Exit 61, I-65 at Peytonsville Road in Williamson County. The Peytonsville Road Interchange suffered a tragedy during construction when a fuel truck hit the newly constructed bridge, killing the driver and destroying the bridge. https://youtu.be/53icZmy34vE
The workshop focused on types of interchanges, the FHWA Interstate Access Policy, design, traffic operations, and safety. TDOT is in the process of changing several of our interchanges around the state, so I thought I would share with you the more popular types of interchanges and why they’re used.
Single Point Urban Interchange (SPUI):
Tight Urban Diamond
Diverging Diamond Interchange:
We look forward to continuing to work with TDOT on Interstate Access Requests. These projects utilize multiple Sain Associates teams – Transportation, Traffic, and GIS – and require close teamwork with TDOT.