As recently as March, Daimler AG, the German carmaker, promised to put 10,000 autonomous taxis on the streets by 2021. But last week, Daimler chairman Ola Kaellenius announced that the company was taking a "reality check” on the project and focusing on self-driving long-haul trucks instead. It’s fine that self-driving cabs aren’t coming as fast as some expected – and it’s even better that Silicon Valley-style big talk appears to be going out of fashion.

Kaellenius’s "reality check” has some solid business reasons: Daimler is cutting costs and can’t commit to a large, capital-intensive project without a clear idea of what kind of first-mover advantage it might confer. But mostly, it comes because of a long-obvious technical problem. Making sure self-driving cars aren’t a menace in city traffic is a job that’ll take more than a couple of years. Investigators are still trying to get to the bottom of the March 2018 accident in which a driverless Uber killed a pedestrian in Tempe, Arizona, and it appears Uber Inc’s cars had been involved in dozens of previous non-fatal incidents in the course of the same testing programme.