CALIFORNIA STATE EDITION
A Supplement to:
August 11 2024 Vol. V • No. 16
“The Nation’s Best Read Construction Newspaper… Founded in 1957.” Your California Connection – Sharon Swanson – 1-760-518-4336 – sswanson@cegltd.com
Graniterock’s Critical Turbo Project Improves Safety By Irwin Rapoport
At the eastern end of the ongoing San Benito Route 156 Project that will be completed in fall 2025, Graniterock completed the building of the SR 156/25 Turbo Roundabout Project. Crews began work on this project in San Benito County in June 2022. “This was a critical safety project that immediately reduced the number and severity of collisions, while maintaining traffic flow and efficiency at the intersection,” said Jim Shivers, a Caltrans District 5 public information officer. “A turbo roundabout is an innovative, new facility design that operates similar to a regular roundabout, but has additional features that reduce the potential for collisions.” Some of those additional features include: • A second circulatory lane is inserted opposite of at least one entry lane; • Each segment of the roundabout includes one circulatory lane from which drivers can choose whether to exit or continue around the roundabout; • The diameter of the roundabout is kept small to encourage lower speeds through the roundabout. • Approach legs and entry are typically at right angles to the roundabout.
CEG CORRESPONDENT
Contractor Challenges Traffic was a construction challenge in more ways than one. “One was constructing and completing our work while also maintaining traffic on 25 and 156,” said Graniterock Project Manager Mark Hurley Jr. “We weren’t allowed to close any lanes during the day. We had to let all traffic through and provide at least one thru lane in each direction.” The work was divided into five stages. “Constructing a project with that many stages is somewhat difficult, making sure that we took up from where we left off on the previous days and we’re not missing any sections of our work,” said Hurley.
General contractor Graniterock has completed the state’s first “turbo” roundabout to improve safety and reduce collisions as part of California’s San Benito Route 156 Project.
Impediments also prevented the work from starting as originally scheduled. “We had to go through a couple of winter suspensions in 2021 and when we got some clear weather in the spring of 2022,” said Hurley, “we started and then realized the temporary signal plan that was provided really wasn’t a way to construct that and not close or keep traffic flowing. We had to work with Caltrans and our electrical subcontractor to revise the temporary signal plans and ended up putting forward a value engineering proposal. This took the entire summer and by the time we figured all that out, we didn’t get started until the beginning of winter that year and then we see TURBO page 8
This intersection serves commuters and important goods movement for the region and has been experiencing a pattern of broadside and rear end collisions — more than twice the number of collisions as similar intersections in California.