One month after Tesla put its driverless Cybercab into paid service in Austin, the company has nearly quadrupled its authorized Texas fleet, from 45 vehicles to 169, according to state motor vehicle records, while riders report waits, wrong drop-offs and trunk lids that won’t close.

The bronze two-seaters, which have no steering wheel, pedals, rear or sideview mirrors or outside door handles, drew mixed reviews from paying passengers after the Sept. 3 launch, with videos and posts showing lengthy waits, pickups and drop-offs in the wrong spots and trouble with the butterfly doors.

Elon Musk needs the Robotaxi business to work. Tesla’s auto sales have been sluggish for an extended stretch, and the stock is down 18 percent this year, the only megacap technology company with negative returns. On Friday, the company reported better-than-expected third-quarter deliveries, lifting shares almost 5 percent, but deliveries still fell 2 percent from a year earlier as Chinese makers like BYD and Xiaomi press into Tesla’s markets, particularly in Europe and Asia.

The rival to beat is Waymo. Alphabet’s self-driving unit had 1,154 autonomous vehicles authorized in Texas as of Friday, including 359 of its newer Ojai models, runs more than 500,000 paid rides a week and has completed 270 million fully autonomous commercial miles domestically. It operates in 15 U.S. markets with 15 more planned, plus London, Tokyo and Munich.

Tesla’s Austin service, its only Cybercab market, also fields 420 Model Y vehicles running its automated driving software. Austin has drawn early robotaxi operators with relatively loose state regulation and a deep tech community; Amazon’s Zoox is testing there too.

Expansion brings new friction. The National Highway Traffic Safety Administration opened an audit query after the launch to check federal safety compliance, and Tesla won an extension on its Sept. 30 deadline to answer a long list of questions, an agency spokesman told CNBC by email. Tesla did not immediately respond to a request for comment.

Ethan McKanna, a 20-year-old Texas A&M computer science sophomore and former Tesla intern, has caught about 30 Cybercab rides and built a site, RobotaxiTracker.com, that analyzes traffic-camera feeds and public records to track autonomous services in U.S. cities. He likes the Cybercab’s “own space with access to a massive screen, media controls and apps” and called the ride “very smooth.” The pickup and drop-off experience needs work, he said, and the butterfly doors are “less convenient” than sliding ones. Early on, he said, “wait times were often like 45 minutes plus,” though that has eased. “Waymo’s been doing commercial operations for longer, so they’re just more mature with 24/7 service, better support, things like that,” Mr. McKanna said, recalling that early Waymo rides in Austin had their own “harsh braking” problems.

No collisions or serious safety incidents involving a Cybercab have been reported in Austin since the commercial debut. Still, first responders are wary. Matt McElearney, an Austin fire captain, said Tesla gave detailed emergency guidelines and thorough instruction, but he wants state or federal rules requiring any robotaxi without manual controls to offer a way for “public safety representatives to take control — move, steer, or shut down an AV — in both emergent or non-emergent events.” Because performance can shift with software updates, he added, autonomous vehicles should have to pass testing “through the entire lifespan of the product.”

The public has its doubts. In a September survey by Slingshot Strategies, 50 percent of U.S. respondents said they would not feel comfortable riding in a robotaxi with no steering wheel or pedals, and 70 percent said Tesla should pause rides after learning of the NHTSA inquiry.

Mr. Musk’s plans assume that changes. Next come San Antonio, Dallas and other Texas cities, then Nevada and Florida, where warm weather and friendly rules await. In January, he said at Davos that the robotaxis would be “very, very widespread” in the United States by the end of 2026. In California, Tesla still lacks permits to run public roads without a human at the wheel.

After Friday’s delivery report, Cantor analysts pointed to the payoff. “Management previously said that once production ramps, it expects Cybercab to ultimately be the largest volume vehicle in its lineup,” they wrote.