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Study says red lanes make Mission safer, faster

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Analysis monitored 7,500 drivers over 10 months

Cars and a Muni bus on Mission Street, with red traffic lanes. Torbak Hopper

A year ago, the city painted bus lanes in Mission Street bright red. And then all hell broke loose.

Although neighbors complained, including merchants who said that the unpleasant look of the streets and the forced right turn rules hurt their business, the city insisted that the changes would make traffic on the busy street faster and safer, particularly for Muni.

Eleven months later, local tech outfit Zendrive chimed in with its own findings, suggesting that the city’s expectations did bear out in the end.

Zendrive is a San Francisco-based startup founded in 2013 that studies traffic by analyzing driver behavior via smartphone censor.

According to TechCrunch, “[the] company targets enterprise customers like on-demand services and trucking companies that have large fleets of cars and trucks on the road, charging them licensing fees for its safety insights.”

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Which turns out to be potentially useful for municipal principalities as well. Zendrive compiled data from 7,500 users on Mission Street between January 2016 (prior to the lane change) and October that same year (about six months later) and compared how behavior changed.

These results of course hinge on how reliable Zendrive’s technology turns out to be. Even so, the company found that in the months after SFMTA program went into effect, potentially dangerous driving behaviors declined:

  • Speeding was down 36 percent over 10 months.
  • “Aggressive acceleration” went down 30 percent.
  • Hard braking declined by 21 percent.
  • Cell phone use behind the wheel went down eight percent.

Technically, no one can prove a causal relationship between these behaviors and the lane changes. But it’s clearly the most likely explanation.

The authors of the Zendrive study do note the negative reaction from many in the community (in terms that make it clear they’ve been reading Curbed SF’s coverage of it):

Locals have used phrases like “rage-provoking project,” “gentrification on steroids," and even "ethnic cleansing of the Mission.” [...] Local business groups complained that shops closed and workers were laid off since the project went into effect. Merchants alleged that the forced turns made it impossible to find parking, and that the lanes created a hostile "psychological barrier" that scared off customers

But driver behavior is the bottom line. Although a policy manager at the Mission Economic Development Agency had a different take on Zendrive’s data, telling the San Francisco Examiner “[What] that study really demonstrates, and is misleading about SFMTA’s current data, is there are less cars on Mission Street.”