Transportation

New ‘turbo’ roundabout planned for 25/156 intersection

Key feature includes raised dividers to prevent motorists from changing lanes.

Having obtained the $12 million required for the job, Caltrans is set to begin the bidding process for the State Route 25/Highway 156 roundabout project. Construction is expected to begin in January, pending weather conditions. 

Caltrans project manager Brandy Rider said the roundabout planned at that intersection will be the first of its kind in California. The design known as a turbo roundabout is 240 feet in diameter, includes raised dividers to keep motorists from changing lanes, and uses overhead and road markings for navigation.

“It could be a model for California in the future,” Rider said. 

Rider said the overhead lane markings, noting which lane leads to either Route 25 or Highway 156, will be placed about 350 feet from the roundabout. 

The intersection became a high priority for Caltrans because it has almost double the average rate of collisions. According to Caltrans, there were 126 collisions between 2009 and 2018 with two fatalities. 

Rider said Caltrans will be working on an easy-to-understand design they intend to present at public hearings in the future. She noted that the engineer’s design may be difficult for the public to understand as it contains a lot more information than just the drawings of the lanes. 

25/101 roundabout engineer design. Photo courtesy of Brandy Rider.
25/101 roundabout engineer design. Photo courtesy of Brandy Rider.

Rider said the roundabout design is similar to one being constructed in Jacksonville, Florida. According to the video (see below) provided by Rider, the turbo roundabout was recently invented in the Netherlands. Its key feature is that it prevents drivers from changing lanes, thus reducing rates of roundabout collisions. 

“The roundabout, once everyone is used to using it and using it properly, it’s actually a lot more efficient at moving vehicles through it,” said Andrew Rodgers with AVP Construction and Capital Projects in the video.

Based on public comments and safety concerns voiced by residents with the design, Rider said Caltrans increased the diameter—from 190 feet to 240 feet—of the project to shift from a conventional design to the turbo roundabout. 

She added Caltrans did not have to deal with property acquisition for this project as it stayed within the existing right-of-way.

In addition, she said the overpass that is planned at that intersection as part of the Highway 25 widening project, will not be constructed over the roundabout. Instead, Caltrans is working on designs that may incorporate aspects of the roundabout to the overpass, which would save money along the way.

 

 

We need your help. Support local, independent news. BenitoLink is a nonprofit news website that reports on San Benito County. Our team is committed to this community and providing essential, accurate information to our fellow residents. It is expensive to produce local news and community support is what keeps the news flowing. Please consider supporting BenitoLink, San Benito County’s news.

Noe Magaña

Noe Magaña is a BenitoLink reporter. He also experiments with videography and photography. A San Benito High School alumnus with a bachelor's in journalism from San Jose State and a Liberal Arts Associate's Degree from Gavilan College. Noe also attended San Jose City College and was the managing editor for the City College Times, the school's newspaper. He also was a reporter and later a copy editor for San Jose State's Spartan Daily.