Who speeds more often? Taxis or ride-share drivers?

Carrying cell phones with ride-monitoring software, “secret shopper passengers” took hundreds of rides with Uber, Lyft, Sidecar and taxicabs in San Francisco last summer. Another cohort, recruited from Craigslist, drove their own cars with the monitoring software on their phones. San Francisco startup Zendrive sponsored the study, which used its technology to analyze driver behavior.