The Alphabet Inc. unit, which operates its commercial ride service in three major cities and is adding a fourth, is starting to generate significant revenue. But safety concerns persist.br br Read the full story on Forbes: br Subscribe to FORBES: br Fuel your success with Forbes. Gain unlimited access to premium journalism, including breaking news, groundbreaking in-depth reported stories, daily digests and more. Plus, members get a front-row seat at members-only events with leading thinkers and doers, access to premium video that can help you get ahead, an ad-light experience, early access to select products including NFT drops and more:br br br Stay Connectedbr Forbes newsletters: Forbes on Facebook: Forbes Video on Twitter: Forbes Video on Instagram: More From Forbes: br Forbes covers the intersection of entrepreneurship, wealth, technology, business and lifestyle with a focus on people and success.