When a confused Waymo robotaxi blocked an ambulance from reaching the scene of last weekend's mass shooting in Austin, it wasn't a remote Waymo agent coming to the rescue.

• Instead, it was a local police officer who got in and manually drove the car out of the way.

Why it matters: The incident exposes the limits of remote supervision systems in AV networks when vehicles — or the public — need urgent intervention.

Driving the news: Few situations are more complex than a mass shooting, like the one that unfolded early Sunday morning in Austin.

• A Waymo robotaxi picking up a passenger near the shooting scene blocked an ambulance, according to a bystander video circulating on social media and confirmed by Waymo and Austin-Travis County EMS.
• The nearly two-minute video shows the Waymo stopped sideways in the road, as it attempted to make a U-turn amid the chaos, with an ambulance behind it trying to get by.

How it works: Waymo's remote assistants don't directly control the cars, the company explained in a blog post and a letter to U.S. Sen. Edward Markey (D-Mass.) after a recent committee hearing.

• They respond to specific requests from the robotaxi when its driving system asks for help, providing digital guidance to help the vehicle navigate tricky situations, like construction zones.

A police officer arrived about 30 seconds into the video of the standoff, and used his cellphone to scan a QR code on the side of the vehicle to contact Waymo specialists, following protocol in Waymo's training guide for emergency responders.

• He was able to access the vehicle and climb into the front seat and communicate with Waymo to disengage the autonomous driving system and manually drive it into a nearby parking garage.
• The entire episode lasted under three minutes, according to Waymo.

The big picture: Congress has started asking questions about how remote assistance works in autonomous vehicles. Much of that concern has focused on how supervisors located far away — in Waymo's case, some of them 8,500 miles away in the Philippines — could pose risks to passengers, other drivers or even national security.

Between the lines

Waymo is accelerating its rollout of robotaxis in the U.S., adding four new cities in Texas and Florida last month, as self-driving technology begins to penetrate mainstream America.

Why it matters: Armed with $16 billion in fresh capital from parent Alphabet and others, Waymo is quickly extending its lead over other players like Tesla and Amazon-owned Zoox, which are still mostly in testing mode.

The newest markets are Houston, Dallas, San Antonio and Orlando.

By the numbers: Now in 10 cities, Waymo has doubled the number of markets it serves in a matter of months.

• It's laying the groundwork for service in at least 20 cities, and is on track to provide more than 1 million driverless rides per week by the end of the year.
• It has about 3,000 robotaxis deployed nationwide, more than one-third of them in the San Francisco Bay area.

What we're watching: Waymo's robotaxis are adapting quickly to new markets, but basic operational challenges — such as charging and maintenance — could constrain network growth.

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Axios Miami's Martin Vassolo tested one of the company's self-driving cars earlier this year.

His experience: The Waymo team set him up on a preplanned, 30-minute roundtrip ride.

✅ Do's:

• Tap the tablet: The in-car screen allows passengers to control music, climate and ride functions.
• Wear your seatbelt. It's the right call in every ride ... but the Waymo won't start moving until you do buckle up.
• Try out the back right seat. You get a good view of the steering wheel spinning to make turns (if that sight doesn't freak you out).

❌ Don'ts

• Don't sit in the driver's seat. Feel free to sit shotgun, however.
• Don't touch the steering wheel or other driving controls. "Somebody from rider support will get on and say, 'Please don't do that,'" Waymo's Ethan Teicher tells Axios.
• Don't expect the vehicle to speed. The vehicle follows the rules of the road and does not mimic other drivers' behaviors.

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