After years of work, Waymo — Alphabet’s self-driving subsidiary — has finally unveiled its driverless taxi service. Dubbed Waymo One, it is available to locals in some Arizona suburbs. To use the service, riders must download Waymo’s ride-hailing app and provide a credit-card number. This allows them to see price estimates before accepting a trip without a driver. Waymo chief John Krafcik says the service will, “make the roads safer and easier for everyone to navigate”.

The launch comes at an important time. A Google spin-off, Waymo has spent more than $1bn on developing self-driving technology and is keen to recoup that cash. The company also wants to establish a foothold in a space that could be worth more than $7tn globally each year by 2050. Competitors including Ford, General Motors and Mercedes hold similar aspirations. All three are expected to launch robotaxi services. For now, Waymo is leading and equity analysts are cheering.

But a close look at Waymo’s operation raises several red flags. For one thing, the launch is restricted to a 100-square-mile area where the company has already spent years running tests. That means the taxis will have to deal with fewer “edge cases” — complex, dangerous situations a self-driving car may be ill-equipped to handle. Unfamiliar left-hand turns would be an example. But limiting operations to one area inevitably limits the service’s appeal, at least initially.