How the car-free policy impacted Market Street traffic
By: Kuan Butts
San Francisco recently closed Market Street — one of our busiest downtown streets — to private vehicles, including ride-sharing companies. Now the twelve blocks between Main Street and 10th Street are only available to streetcars, buses, and commercial vehicles.
The closure is an effort from the city to have a more people-centric design, make the street safer for the more than 500,000 pedestrians who walk along it each day and reduce traffic deaths and serious injuries on roads. It also makes routes more reliable for the 200 buses that travel up and down Market during peak hours.
While we’ve enjoyed the less-stressful walk to our office, many people in San Francisco worried there would be significant increases to traffic and congestion on the streets surrounding the closure. Just a few weeks in, we wondered if those fears were true, and analyzed the impact using our typical and live traffic data.
Analyzing changes using Mapbox traffic data
With our traffic data, we were able to evaluate observed speeds within the area of the Market St. closure with high fidelity. This data features live speed data for 30 billion road segments around the world, updated every five minutes from our 600 million monthly active users.
To evaluate the closure, we examined live speeds from our traffic data during the peak hours of 7–9 AM and 5–7 PM for Monday — Thursday for seven weeks between January 6th and February 20th. We split the seven weeks into 3.5 weeks before the close and 3.5 weeks after.
We then calculated the average speed for the fourteen days before and after the closure to check for any significant changes. Interestingly, we found there was no meaningful difference in the traffic in either the morning or evening rush hours.
Traffic changes around Market Street
While we saw no significant changes in observed speeds throughout Market Street and its side streets, we did see some segment of Market Street that experienced a change greater than 10% after the closure.
Some outlying segments did exhibit significant increases (greater than 30%) in speeds relative to their speeds prior to the closure including areas between 1st and 2nd street, near Embarcadero on the northeast end of Market Street. However, a few segments actually saw reductions in speeds. These areas were primarily between 7th and 8th Street, near Civic Center on the southwest end of Market Street. In general, this closure has improved traffic speeds along Market Street, with most observed speed increases happening northeast of 5th Street.
Along Market Street itself, we saw an insignificant change of less than 2 MPH after the Market Street closure. Looking at the immediate intersections of Market Street, we saw there no major changes while a few cross streets — like Geary and Bush — had a slight increase in traffic speed.
So the impact is mixed — we don’t see significantly faster traffic, but it also didn’t have an overall negative impact on traffic. Most importantly, we saw that half of the most dangerous intersections for pedestrians and cyclists along Market Street are now less congested.
Looking at the closure as a whole
Finally, we took a look at the whole closure. We can see that for the most part, speeds of vehicle traffic on and around Market Street remain unchanged, with key parallel streets in the South of Mission neighborhood (Folsom, Howard, and Mission) showing similar speeds before and after the closure.
The Market Street closure has been a huge win for commuters’ safety, and we’re interested in continuing to watch its long-lasting impacts. Interested in digging into problems about how traffic affects everyday commutes? Or just interested in working on a platform that powers over 45,000 apps, touched by over 600 million people each month, and processes data at a petabyte-scale? Apply to work with my team at Mapbox!
