It was just a matter of time.

As someone who spent his prime driving years in Buffalo, NY, the notion of self-driving cars has struck me as pretty absurd. Thus far the guidance systems for these cars tend to miss potholes and black ice. They are hardly better at avoiding lurching pedestrians, like drunken revellers hopping across busy streets from one bar to another (or jumping off a balcony and hoping to hit a snowbank but missing).

Uber’s attempt to test-launch its autonomous vehicles in San Francisco this month did not go well.

Without permits from the California Department of Motor Vehicles, the company rolled out self-driving cars in San Francisco, albeit the kind that have a human pilot in the front seat just in case. The cars were almost immediately caught running red lights and stop signs and barely missing pedestrians, prompting the DMV and state Attorney General Kamala Harris to demand that they cease operations. Uber refused, citing an “important issue of principle.”

Days later, Uber acknowledged that the vehicles have a problem with unsafe turns across bike lanes, something they knew in pre-launch tests before placing the cars on roadways with lots of bikes, like in San Francisco. It must have been an important principle or something. Eventually, Uber bugged out of San Francisco after the DMV revoked registration on all its vehicles. But don’t weep for Uber: Arizona Gov. Doug Ducey welcomed them into the state for a pilot project in Phoenix.

Maybe concerns about beta-testing robotic steel projectiles alongside American citizens amount to mere griping. But it actually reveals a core conundrum with this whole self-driving car model. Most experts on autonomous vehicles believe that only real-world field tests, not simulations, will refine the technology so it can interact with often imperfect and irrational humans without killing them. Yes, ordinary humans kill 35,000 people a year while driving, but I suspect people will have far less tolerance for machine errors leading to similar levels of carnage.

h/t eschaton