Protected bicycle lanes are popping up in cities all over the country. The number of these lanes, also called cycle tracks, has more than tripled in the past five years.
But what happens when cyclists reach an intersection? The buffers that separate bike lanes from car traffic such as medians, planters, even parking spaces, disappear and bikers are on their own.
The solution: an intersection design that continues the protected lane with a layout that improves sightlines and guides cyclists, drivers, and pedestrians through seamlessly.
“A collection of design elements makes left turns simple and secure, right turns protected and fast, and provides straight through movements that minimize or eliminate conflicts from turning cars,” says Nick Falbo, senior planner for Alta Planning + Design. “The model can be adapted even on streets without protected bike lanes.”
Davis intersection first to open
In the past year, such intersections have been built in several cities, including Davis, Calif. Home of the Bicycling Hall of Fame, the city launched its cycling network in 1966, installed the nation’s first cycle signal in the 1990s, and has a bicycle commuting rate of 22%.
Davis’ protected intersection sits at the entrance of the Cannery, a new 100-acre mixed-use development of low- to high-density residential and agricultural areas, parks, and greenbelts.
The initial plan was to separate traffic with multimillion-dollar grade-separated crossings for bicycles and pedestrians. But when the city council reviewed the proposal in April 2014, council member Brett Lee offered a different idea. An engineer and avid cyclist, he advocated for a protected intersection design he’d encountered when cycling in the Netherlands.
Davis tapped the Dutch consulting firm Mobycon, which recommended using at-grade crossings rather than bridges or tunnels. This would give commuters and Cannery residents direct access to bicycle lanes on the intersecting streets and overshoot a nearby shopping plaza. The council approved the Dutch-style intersection in September 2014.
Cannery developer The New Home Company collaborated with the city on the design, which was completed in May 2015, and funded the $1 million construction project, which was completed in August.
Feedback from drivers and cyclists has been “mostly positive,” says Public Works Senior Civil Engineer Roxanne Namazi. “We’ll construct more similar intersections.”
Salt Lake City
Meanwhile, Salt Lake City was tackling a traffic flow issue that arose from plans to build a new cycle track on a major thoroughfare that would cross an existing protected bike lane at the intersection of 200 West and 300 South.
Salt Lake City Transportation Project Manager Colin Quinn-Hurst laid out potential solutions and Falbo came in with Alta Planning + Design to help evaluate alternatives. Working closely with Alta, project manager Brian Christensen of Horrocks Engineers implemented the design.
A Dutch-style intersection was the most practical and functional design. “It provided a solution for the two intersecting bike lanes,” says Salt Lake City Transportation Director Robin Hutcheson. “Also, the location has high pedestrian traffic and the design improved pedestrian safety.”
Salt Lake City streets are wide, allowing higher speeds. The protected intersection narrows the space and reduces the number of lanes, slowing cars down. This was a plus; at 7,000 cars per day, the low-volume intersection was operating below traffic capacity. “We accomplished this innovative design with a very minimal additional cost margin,” Hutcheson says.
The intersection opened in October 2015. In other cities:
The first U.S. protected intersection appeared in September 2014 in Austin, Texas. Located in an uninhabited part of a new development, it is not yet in use. The city has several more planned.
- Earlier this year, Chicago unveiled its first protected intersection downtown at Washington and Franklin streets. As part of the Loop Link bus rapid transit project, similar designs are planned for four more intersections.
- A major revamp of Boston’s Commonwealth Avenue, scheduled for completion in 2017, will include new cycle tracks and protected intersections.
The design has been called hard to explain but easy to use.
As reported in the Davis Enterprise, when the Davis intersection opened:
“There were no standing diagrams on the street, no big street signs attached to traffic light poles announcing the difference between a standard American intersection and the Dutch-styled one people were passing through.
Similarly, in Salt Lake City, “people liked it and used it before all the markings and colored paint were in place,” says Hutcheson. “It’s very intuitive.”
Cost and space considerations
Incorporating protected intersections into new construction has little impact on costs because elements such as drainage, signals, and curb placement are designed from scratch. However, when converting existing intersections, “moving drainage can be a major cost,” Falbo says.
Lane reduction projects are good candidates because they allow plenty of room for reconfiguration. For example, Salt Lake City’s protected intersection was more affordable because it didn’t involve changing the drainage.
Protected intersections occupy about the same footprint as a traditional intersection using right-turn channelization. The right-turn lanes are replaced with a combination of the cycle track and its protective barriers. At the intersection, cyclists turning right simply continue in the bike lane. “This prioritizes comfortable, safe bike movement instead of fast car turning,” says Falbo.
“The smaller the intersection, the trickier it gets with tight turns and large vehicles,” he adds. Options for accommodating turns by large vehicles include mountable truck aprons and a separate corner radius.
Salt Lake City’s protected intersection has few trucks. “We designed a mountable curb on the bulb-out so fire trucks could navigate turns,” says Hutcheson. Still, there was an early instance where an 18-wheeler got stuck and had to back out. The city also trained delivery company drivers on how to use the intersection.
Overall, the department is satisfied with its first protected intersection.
“We’re happy with the performance and the acceptance into the fabric of downtown,” says Hutcheson. “I was probably the most nervous. Almost every day I would go down to the intersection and watch for issues we didn’t anticipate. However, it went according to plan.”
Diana Granitto is a freelance writer based in suburban Chicago. E-mail firstname.lastname@example.org.