Every morning and afternoon on their way to and from MLK Jr Middle School, hundreds of kids walk and bike past the North Berkeley library at the corner of The Alameda and Hopkins. And throughout the day, people are going to and from the library itself and the King pool and playground down the street. Add in 22,000 cars a day and a really wide intersection.
To make it safer for kids to cross at the intersection of The Alameda and Hopkins right in front of the library, Berkeley is shortening the crosswalks and narrowing the wide dimensions of the intersection. Pedestrian bulb outs, right? No, a protected intersection, the first in the East Bay and sixth nationally. With existing bike lanes on The Alameda and Hopkins, the new intersection design should improve your safety bicycling and walking.
This drawing shows the basic concept of modifying an existing intersection with protected elements. Berkeley’s protected intersection has similar protection, but differs in design in that on-street parking remains with Berkeley’s project. Each corner of the intersection includes a raised protective curb outside the bike lane that moves curbside, and a raised corner safety island to create a tighter right-turn radius for cars, and this is a key feature of a protected intersection. The corner island slows turning traffic and provides queuing space for the turning car outside of the thru-lane, allowing the car to wait for bicyclists and pedestrians to proceed forward through the intersection without blocking traffic. The whole design is essentially bulb outs designed with bike lanes.
Here is Berkeley’s construction drawing:
Notice the raised curb elements on the approach and the corner islands. By adding corner islands, the bike lane bends out a little bit, but not much. You will get to experience Berkeley’s protected intersection and see how well it works at that specific location, but also to get a sense of how the concept of a protected intersection works and how its protective elements could be applied on other bikeways.
To make a left turn as a bicyclist through a protected intersection, you make a two stage left turn. First you proceed straight across the intersection to the far corner, and then you wait for the traffic light to change, and when it does, you proceed in the left direction of your turn. You can also make a legal left turn as you currently do out in traffic and as shown here, but protected intersections get rid of the requirement that you have to be out in traffic to make a left turn.
More on protected intersections here.
It’s interesting how the design of this intersection came about. In 2010, Berkeley received a Safe Routes to School grant to add bulb outs at this busy intersection. Added bulb outs would shorten crossing distances for walking and place pedestrians where they are more visible to drivers. But bulb outs come with one added design challenge–they change how water drains on the street, because bulb outs change the curb line.
The project was delayed due to engineering staff constraints, and when Caltrans threatened to rescind the grant, Berkeley jumped into action. They quickly learned about the design challenges of drainage and figured out that the issue is minimized if they move the bulb outs into the street, maintaining existing curb lines and water drainage. Bulb outs in the street start to look a lot like a protected intersection, especially when you move the bike lane behind the bulb outs. This is essentially what Berkeley has done, and the clever design saves Berkeley money and expedites the project.