For Jonathan Matus, the new turn restrictions on Market Street that went into effect last summer weren’t a problem — they were a unique opportunity to put his company’s software to the test on its home turf.

Matus’s company, Zendrive, doesn’t make an app for consumers. Instead, its software goes inside apps like HopSkipDrive, a child-ride service, and SherpaShare, a mileage tracker used by Uber and Lyft drivers, and uses smartphone sensors to track drivers.

Both traffic and risky driving on San Francisco’s main thoroughfare have declined since the city implemented its Safer Market Street program, according to Zendrive, which gets to analyze the data its customers generate.

The experiment showcased how San Francisco startups like Zendrive are using the city as a testbed for new technologies — often with the city’s blessing.

Safer Market, which took effect Aug. 11, prohibits most private vehicles from turning onto Market between Third and Eighth and forces eastbound vehicles to turn right off Market. Anecdotally many drivers and others have already seen the difference: that section of Market appears less congested, has more bicyclists and occasionally even seems quiet. But Zendrive’s report is the first to quantify the changes.

“Our deep dive into analytics around the (Safer Market) policy indicated that it worked in reducing unsafe behavior on the road, making Market safer for pedestrians and cyclists, which is really exciting,” said Matus, Zendrive’s co-founder and CEO. “Simplifying the intersections resulted in smooth traffic flow.”

The San Francisco startup said its study tracked 2,000 cars and 100,000 trips over a period spanning a month before Safer Market’s implementation until about six months later.

The before-and-after analysis found a 22 percent decrease in traffic volume on the targeted segment of Market over the six months — somewhat less than the 30 percent to 50 percent that planners had anticipated.

Two factors often involved in collisions declined noticeably. Speeding fell by an average 72 percent and hard braking by 37 percent. Those numbers were normalized to account for the reduction in traffic volume.

Surprisingly, Zendrive detected a “positive ripple effect” on neighboring Mission Street, which parallels Market a block away. Mission had a 56 percent reduction in speeding and 47 percent reduction in hard braking, Zendrive said, attributing that to a “network effect” in which changes in driving behavior carry over to nearby areas. Traffic volume on Mission was unchanged, it said.

“It’s encouraging to see the private sector focus attention on solving city transportation challenges,” said Paul Rose, a spokesman for the SF Municipal Transportation Agency. “To have outside organizations like Zendrive take a look at how we’re making our streets as safe as possible is beneficial to everyone who uses these roadways.”

The MTA will release its own study of Safer Market, but not until the end of the year. However, it will be able to include some findings that Zendrive didn’t look at, such as whether Muni buses increased their on-time behavior and how often vehicles flouted the laws barring them from transit only lanes, for instance.

Back to Gallery Zendrive test finds Safer Market Street turn restrictions... 6 1 of 6 Photo: Michael Macor, The Chronicle 2 of 6 Photo: Michael Macor, The Chronicle 3 of 6 Photo: Michael Macor, The Chronicle 4 of 6 Photo: Michael Macor, The Chronicle 5 of 6 Photo: Michael Macor, The Chronicle 6 of 6 Photo: Michael Macor, The Chronicle











Backed by $15 million in venture funding, Zendrive aims to make roads safer using data and analytics, Matus said. The three-year old company, which has 45 employees, makes money by providing software to companies with fleets of cars or trucks who want to monitor their drivers for safety.

The simple motion and location sensors in smartphones can replace more expensive custom hardware used in fleets, Matus said.

Besides HopSkipDrive and SherpaShare, customers include roadside assistance app Urgently and some taxi companies, Matus said. (Safer Market Street bars Uber and Lyft drivers but allows cabbies.) In May, Life360, an app for families to stay in touch, added new crash-detection and safety features built with Zendrive’s software tools.

Matus would not say which of its customers were part of the Safer Market study, but said the 2,000 vehicles were split evenly between commercial and personal uses.

Carolyn Said is a San Francisco Chronicle staff writer. Email: csaid@sfchronicle.com Twitter: @csaid