Robotaxi fleets scale up as a federal audit tests the Cybercab

In the space of a fortnight, US robotaxis moved several steps closer to fleet scale. On 20 August the Nevada Transportation Authority approved permits for up to 8,000 commercial robotaxis in Clark County, which includes Las Vegas, over the following 12 months. On 1 September Waymo began giving its first public riders fully autonomous trips in Denver, San Diego and Tampa, taking it to 14 cities.

On 3 September Tesla began commercial deployment of a small number of Cybercabs in Austin, Texas. The two-seat vehicle lacks a conventional steering wheel, pedals and mirrors. The same day the National Highway Traffic Safety Administration (NHTSA) opened an audit query into how Tesla had certified the vehicle against federal safety standards, announcing it the following morning. Public riders were admitted from 5pm Central time on 4 September.

The sequence captures where the industry now stands: permission to operate is scaling into the thousands while the physical rulebook for these vehicles is still being rewritten. For organisations that run dispatch, ride-hail or fleet operations, both the opportunity and the risk are becoming concrete.

Nevada puts a ceiling on the table

The Nevada Transportation Authority approved three permits unanimously. Tesla may run up to 5,000 robotaxis, Waymo up to 1,000, and Uber up to 1,000 through its partnerships with Motional and Zoox. According to TechCrunch, Zoox already held its own permit covering 100 robotaxis.

The headline figure is a ceiling, not a deployment plan. Eric Early, Tesla's Cybercab chief engineer, told the authority that the company did not expect to field 5,000 vehicles within a year and would be pleased to reach around 2,500. He said the constraint was not the technology.

The structure of the decision is worth noting. The authority set fleet-wide ceilings for a 12-month window and left the companies to decide how quickly to fill them. Operational readiness, vehicle supply and demand, rather than the permit itself, now set the pace.

Opposition came from the Livery Operators Association and local taxi companies. Attorney Kimberly Maxson-Rushton raised concerns about oversaturation of the commercial transport market and crowded roads, particularly in the Golden Triangle between the airport and Las Vegas Boulevard, where most autonomous vehicle testing has happened so far.

Waymo, Zoox and the platforms in between

Waymo's expansion followed a staged pattern. When it named four new cities in July, including Las Vegas, it said service would start with human drivers and employees only. By 1 September three of them were carrying their first public riders with no one at the wheel, in a service CNBC described as paid, and Waymo said tens of thousands of people had signed up in each city. The progression from human drivers to employees to the public appears designed to build experience in each city before carrying paying riders without anyone at the wheel.

Waymo also says its system is involved in 94% fewer crashes causing serious injury or worse than human drivers. That is a company-reported figure, and it should be read as such.

Scale brings its own exposure. Waymo had about 4,000 vehicles as of May, and that month it was recalling nearly 3,800 of them after some drove into flooded streets in Atlanta and San Antonio, according to the Smart Cities Dive tracker. When one software release runs an entire fleet, a single fault can reach almost every vehicle at once.

Amazon-owned Zoox, which already offers rides in Las Vegas and San Francisco, said it would begin testing in Houston and San Diego in September with human supervisors on board. Uber, meanwhile, is positioning itself as a marketplace for other companies' autonomous vehicles. It began offering Motional robotaxi rides in parts of Las Vegas in March, with a plan to go fully driverless by the end of 2026, and said in May that autonomous trips on its platform had grown more than tenfold in a year.

Uber's Nevada permit, covering vehicles from two autonomy companies, shows that model in regulatory form. The platform holds the permit, and partners supply the driving.

How a vehicle becomes road-legal in the US

In the US, manufacturers certify for themselves that their vehicles meet the Federal Motor Vehicle Safety Standards, known as FMVSS. NHTSA does not sign off each design in advance. It can examine a manufacturer's certification afterwards, which is what it is now doing with Tesla.

The difficulty for purpose-built robotaxis is that many of these standards assume a person at the controls. The light-vehicle brake standard, FMVSS No. 135, currently requires hand- or foot-operated brake controls. A vehicle with no pedals therefore needs an exemption, a rule change, or a defensible argument that particular requirements do not apply to it.

Zoox took the exemption route. After it self-certified its vehicle, which has no steering wheel or pedals, in 2022, NHTSA sought more information and opened an audit query the following year. Zoox also applied for a temporary Part 555 exemption from eight standards, which received final approval in July 2026 and allows it to add 2,500 vehicles a year to its commercial fleet for two years. It now charges for rides in Las Vegas.

The rule-change route is under way but incomplete. On 26 June NHTSA proposed amending FMVSS No. 135 so that brake-control requirements would no longer apply to vehicles designed never to be driven by a human, while stopping-distance requirements would still apply to every vehicle. The comment period ran until 27 July.

Earlier in 2026 the agency issued similar proposals for standards covering transmission controls, windscreen defrosting and wiping, and tyre selection. The modernisation is proceeding one standard at a time. Until that work is finished, the existing standards remain in force.

Each route carries a cost. An exemption brings volume caps and, as Zoox found, a long process. A rule change requires public consultation and time. Arguing that certain standards do not apply is the fastest path to the road, but it exposes the manufacturer to exactly the kind of review now under way.

Approvals to operate autonomous fleets are arriving in the thousands, but the federal rules that define what a road vehicle must physically include are still being rewritten.

What the Cybercab audit is, and what it is not

Tesla told NHTSA that it certified the Cybercab as compliant with all applicable standards and that it plans to expand deployment gradually to more vehicles and locations. The word applicable carries most of the weight. The audit query, numbered AQ26002 and prompted by public information, will examine the process and technical data behind that certification, including how far it rested on Tesla's view that some standards do not apply to the vehicle.

NHTSA's case summary gives the population as an estimated 1,000 vehicles, while the Smart Cities Dive tracker reported that Texas had authorised just 45 Cybercabs. Riders under 13 are not permitted. The cabin is built around passengers, with a 22-inch touchscreen, nine cameras monitoring the interior and seat sensors that switch each seat's airbags on or off as needed. Tesla separately runs Model Y robotaxis in Austin, Dallas, Houston, Miami, Orlando and Tampa.

NHTSA Administrator Jonathan Morrison said the agency supports the safe deployment of automated vehicles, but added that "we need to ensure that all of our laws are followed". The message is that federal support for autonomy does not suspend the rules already on the books.

An open audit query is not a finding, and neither is what came next. On 10 September NHTSA escalated the matter, issuing Tesla a Special Order signed by its chief counsel that sets out 21 detailed requests, including how the Cybercab can be legal to sell without the kind of Part 555 exemption Zoox obtained. Tesla must respond under oath by 30 September 2026, and Electrek reported that false or incomplete answers can bring civil penalties of up to $139 million. NHTSA has still not concluded that the Cybercab is non-compliant or unsafe; the order compels sworn answers, it does not decide the case. The Zoox case, which ran from self-certification in 2022 to a final exemption in July 2026, shows how long the road to a settled position can be.

What is disputed or still unknown

The central legal question is whether Tesla's reading of the standards holds. The case turns on which requirements apply to a vehicle with no manual controls, and that question now sits with the regulator rather than being settled.

The pace of rule changes is also uncertain. The brake proposal and the earlier ones are proposals, not final rules, and TechCrunch noted that existing standards remain in force until that work is complete. Tesla launched before any of those changes took effect, relying instead on its own view of which standards apply, and that view is what NHTSA's inquiry, now escalated to a Special Order, examines.

Real fleet sizes remain unclear. Nevada's permits add up to 8,000 vehicles, but Tesla's own engineer said the company would be satisfied with roughly half of its allocation within a year. Public figures for the Cybercab range from the 45 vehicles Texas has authorised to the 1,000 NHTSA estimates fall within its review. Zoox's exemption, which caps its additions at 2,500 vehicles a year for two years, shows that the exemption route can limit growth as well as allow it.

Safety evidence is uneven. Much of what circulates comes from operators themselves, such as Waymo's crash comparison, while recalls like Waymo's in May show that software faults can surface in public service.

Local acceptance is not guaranteed either. Taxi and livery operators in Las Vegas opposed the permits, and concerns about congestion in the Golden Triangle were raised at the meeting. Permits can be granted quickly, but the conditions attached to them may tighten if those concerns grow.

What this means for mobility and dispatch operators

For teams running dispatch, fleet or ride-hail operations, the question is no longer whether autonomous vehicles will work alongside human drivers. It is how to run a mixed fleet while the rules are still moving.

• Plan for mixed fleets. Design dispatch logic, pricing and customer messaging for a pool that combines human drivers with autonomous vehicles from more than one provider, as Uber's Nevada permit already does.
• Treat permit numbers as ceilings. Base capacity plans on vehicles actually deployed rather than on authorisations; Tesla's own engineer said about half of its Nevada allowance within a year would be a good outcome.
• Check a vehicle's regulatory basis, not just its software. Ask partners whether a vehicle relies on standard certification, an exemption with volume caps or a disputed reading of which standards apply, and what happens to service if that basis changes.
• Build fallbacks for sudden pauses. A recall covering most of a fleet or a certification dispute can take vehicles off the road quickly, so keep human-driven capacity and rerouting rules ready.
• Ask for evidence beyond company-reported safety figures. Contracts should require incident reporting, recall notification and access to relevant operational data.
• Engage local stakeholders early. Objections from incumbent operators and worries about congestion surfaced at the Nevada hearing, so involve city authorities and existing fleet partners before scaling.