In the wake of high-profile incidents in which passengers were allegedly assaulted by their drivers, Uber said today it would improve background checks using methods including biometric scans. "We are initiating research & development on biometrics and voice verification to build custom tools for enhanced driver screening," the company said in a blog post. "We are also investing in ways to provide riders the instant ability to communicate with us and their loved ones in the event of an emergency."

No timeline was given for when the company might roll out new background checks for drivers. Los Angeles and Uber's home city of San Francisco sued Uber this month for misleading customers about background checks, noting that the company does not include a fingerprint check that would stop drivers from passing off someone else's identification as their own.

Meanwhile, Uber shut down operations in the Indian capital of Delhi after one of the company's drivers was arrested on charges that he raped a passenger. "We are reminded by the recent tragic event in India that best-in-class safety must be a constant quest," the company said. "We owe it to all our riders, driver partners and communities around the world to examine what we can do better and then do everything we can to make more progress on safety."