Traffic statistics for the only two roundabouts installed so far along old Highway 101 in North County indicate the devices may be causing more problems than they solve.
Collisions have skyrocketed at a roundabout finished in 2014 near Carlsbad’s border with Oceanside, where the historic highway, known locally as Carlsbad Boulevard, intersects with State Street. After fewer than one collision annually before the installation, 15 collisions were reported in the five years from 2015 through 2019. There were 28 collisions in 2020 through 2024.
Also performing poorly is a roundabout completed in July 2022 in Encinitas, where the old thoroughfare is called North Coast Highway 101. That intersection with El Portal Street recorded just one collision in the 11 years prior to the installation. Since then there have been at least 17 collisions, making it the most hazardous intersection in the city.
Officials in both cities, like many across the state, have promoted roundabouts as a way to slow traffic and make intersections safer for vehicles, bicycles and pedestrians.
People often have strong feelings about roundabouts. Some see them as a way to reduce speeds, lower emissions and prevent fatalities. Others view them as a hazard, especially for people unfamiliar with how to drive through them.
Carlsbad’s city website, based in part on studies by Federal Highway istration, states that generally roundabouts reduce fatalities by 90%, injury collisions by 76%, and all crashes by 35% compared with intersections with traffic lights. Also, the website reports a 33% decline in carbon monoxide emissions and a 46% decline in carbon dioxide emissions because cars are not idling, and a 20% reduction in traffic delays.
However, statistics collected locally show otherwise.
Numbers from a statewide database maintained by the California Highway Patrol show Carlsbad’s State Street intersection, with 15 collisions from 2015 through 2019, was the third-most hazardous in the city. During the same time frame, the intersection at Palomar Airport Road and Melrose Drive had 16 collisions, and an intersection at Palomar and El Camino Real had 18. Both Palomar Airport Road intersections have traffic lights and higher traffic volumes than the roundabout at State Street.
Collisions at the State Street roundabout then nearly doubled during the period from 2020 through 2024, with 28, making it Carlsbad’s most hazardous intersection. Collisions at the two Palomar Airport Road intersections remained about the same.
“Given all of the real-world data … I think people are being misled about the alleged universal safety of roundabouts,” said Steve Linke, a Carlsbad resident and former member of the city’s Traffic Safety and Mobility Commission, in an email on Tuesday.
City officials emphasized that while the number of traffic collisions may be up, relatively few have resulted in severe injuries, and none was fatal.
About half the collisions at both roundabouts were blamed on drivers under the influence of alcohol or drugs. Also, most of the DUI-caused accidents involved a solo driver who hit an object such as a traffic sign or utility pole, not another vehicle. A significant number of drivers were speeding.
“When you look at legal drivers, the intersection performs very well,” Tom Frank, Carlsbad’s transportation director and city engineer, said at an April 29 City Council meeting.
“Drunk drivers have a hard time going through roundabouts, obviously,” Frank said.
One of the arguments for roundabouts is that they almost eliminate the chance of head-on or T-bone collisions that are more likely to be fatal.
At least eight of the collisions in the past 10 years at Carlsbad’s State Street roundabout have involved pedestrians or cyclists. The Tamarack intersection is closer to the beach and sees far more pedestrian s.
“In 2023 at a presentation on this issue, I was appalled when the city traffic engineer … said that a roundabout at Tamarack Avenue and Carlsbad Boulevard would accommodate walkers safely,” said resident Hope Nelson.
“I can’t imagine that a roundabout … would provide more safety than a signal, in fact, considerably less, particularly less,” Nelson said at the April 29 council meeting.
Presented with the statistics, considerable community opposition and facing $19 million in construction costs, the City Council voted April 29 not to advance the plan, in the works for years, to install a roundabout at Carlsbad Boulevard and Tamarack Avenue. Instead, the council approved a $2 million plan to improve pedestrian safety at the intersection.
Linke said he was pleased with the council’s decision to drop the Tamarack roundabout.
“Given the volumes of vehicles, pedestrians, and bicycles at that intersection, I think a roundabout would have been an operational nightmare during peak times,” Linke said. “And the safety records at the other existing roundabouts makes me believe that a roundabout there would be a collision nightmare.”
The City Council also agreed to reconsider at a future meeting a roundabout previously approved, but not yet constructed, for Carlsbad Boulevard at Cannon Road.
As a traffic commissioner, Linke ed the plan for Cannon Road.
“The Cannon Road roundabout has lower pedestrian volume than Tamarack Avenue, and part of the plan at Cannon includes a separate Class I path for pedestrians and cyclists,” he said.
However, he said, he now questions that because of the increasing evidence that shows the traffic control devices have failed to meet expectations elsewhere.
Encinitas officials are monitoring traffic safety at their El Portal roundabout and consider the number of collisions there “relatively low,” said Delilah Welnick, a management analyst for the city.
“The city is planning to install additional roundabouts on North Coast Highway 101 at the intersections of Jupiter and Grandview streets,” Welnick said in an email Thursday.
“These efforts are consistent with broader national research, which shows that roundabouts can significantly reduce the risk of serious injury and fatal collisions when compared to traditional signage or stop-controlled intersections,” she said.
