A crucial safety improvement is being added to streets on scores of projects all over San Francisco, but the importance and impact of this easy-to-add treatment isn’t perfectly clear to everyone.

You’ve probably heard about bulb-outs. Also known as curb extensions, bulb-outs align the curb with the parking lane to increase the visibility of people on the sidewalk and to reduce the distance to cross the street. “Bulb-out” is an umbrella term that can include gateways to neighborhood streets, mid-block street narrowing or boarding areas for public transit.

But why are they so popular?

1. Bulb-outs slow down traffic. Curb extensions decrease the width of streets and can serve as a visual cue for people who drive that they are entering a neighborhood street or area. This helps people at the wheel slow down and become more aware of their surroundings, especially when turning.
2. Increased visibility of people on sidewalks: Extending the sidewalk further into the street increases the visibility of people on the sidewalk and crossing the street.
3. Decreasing crossing distances: Bulb-outs reduce the distance needed to cross, which creates more time for signal changes that prioritize people walking. Along with traffic signal timing that gives people walking a head start, bulb-outs can be a big improvement to the visibility and safety of people crossing streets.
4. Providing more shared public space: More room on the sidewalk allows more room for neighborhood amenities like benches, drinking fountains, bike parking, trees and rain gardens — all great ways to beautify the neighborhood. You can spot a good example at 24th and Harrison streets in the Mission.
5. Improving bus travel times: Extending the curb aligns the bus stop with the parking lane and allows buses to stop and board passengers without leaving the travel lane. This helps buses move faster by decreasing the amount of time lost when merging in and out of traffic.

You can spot bulb-outs all around San Francisco, for example on Valencia between 15th and 19th streets and along Fell and Oak streets between Scott and Baker. More are in the works with street improvement projects like Geary Bus Rapid Transit, the Masonic Avenue Streetscape Improvement Project and the Polk Street Project. We are excited to see more of these safety measures around the city to prioritize people walking and biking on the streets.

This SF bulb-out shows how they extend the sidewalk and create more space for bike parking and other amenities.

Along with our 10,000-plus members, the SF Bicycle Coalition is campaigning for safety improvements for people walking, biking and driving in every neighborhood across our city. Join our community of members supporting this advocacy and elevate the voice of people committed to more bikeable, livable streets.