A California city is preparing to open a $15 million “turbo roundabout” to help solve problems at a deadly intersection, despite concerns from planners that the European road feature could confuse motorists.
The three-lane highway system – called turbo for its shape rather than its speed – is only the second of its kind in the U.S. and is being introduced at the busy intersection of highways 25 and 156 in San Benito County.
The site has double the traffic accident rate of similar intersections in the state. In 2022 there were 45 collisions, including one death.
But while city planners hope the giant roundabout will provide a solution to the dangerous crossing when it fully opens in the spring, they acknowledge the design – originally conceived in the Netherlands – could be complicated for motorists.
The California Department of Transportation, CalTrans, partnered with San Benito County governments to release a video with step-by-step instructions on how to use the roundabout.
A 'turbo roundabout' opens at the intersection of highways 25 and 156 in San Benito County, where a high number of collisions have historically occurred
The roundabout will cost almost $15 million to build and should be fully opened in spring 2024
It explains how the structure will have three lanes separated by 3-inch-high dividers that will direct motorists through the roundabout.
The purpose of the dividers is to discourage lane changing as soon as a vehicle enters the roundabout.
Instead, motorists will have to choose their lane using the overhead signs before entering and follow them until they reach the desired exit.
The left lane is intended for motorists turning left or driving straight ahead from the roundabout.
The center lane is for vehicles going straight, while the right lane is for motorists turning right.
Drivers must yield to traffic already in the roundabout before entering and must stay within their lane until they reach the exit.
This differs from a typical multi-lane roundabout where motorists can move freely between lanes.
Although the name 'turbo' suggests high speed, this refers to the spiral shape of the structure and motorists are encouraged to slow down before approaching.
The roundabout has dedicated lanes for each exit that drivers must select before joining the system
Concerned that the system could be confusing, city planners released a step-by-step instructional video on how to use the roundabout
When entering, motorists must choose the lane corresponding to their exit and stick to it. They are discouraged from changing lanes by three-inch dividers that direct vehicles through the system
“Everywhere we've built a roundabout, the number of collisions is dramatically reduced,” said Caltrans spokesman Jim Shivers. SF port. “And this pretty much applies to roundabouts across the country.”
The only other turbo roundabout in the US is in Jacksonville, Florida and opened in February 2022.
Turbo roundabouts first emerged in the Netherlands in the 1990s, designed by professor LGH Fortuijn as a means to improve safety.
They became so popular that the Dutch government introduced its own guidelines for them and today there are about 300 in the country.
Construction on the San Benito County roundabout began in December 2022 and it has already opened to some traffic with no collisions reported yet.
Before the turbo roundabout, Caltrans said it had implemented numerous other solutions to improve safety, including adjusting signal timing, installing “signal ahead” signs, installing flashing lights and improving the size of signal heads , but with little effect.
It said an exchange was not being considered due to funding issues and the need to quickly address security concerns in the area.
The turbo roundabout is only the second of its kind in the US and follows the construction of a similar roundabout in Jacksonville, Florida
Despite being a common sight in many European countries, traditional roundabouts are rare in the US.
There are approximately 13,000 in the entire country, which equates to one per 25,531 inhabitants.
By comparison, there are 25,000 in Britain, which works out to about 383 per capita, and over 30,000 in France, which operates at about 664 per capita.