Six weeks after proudly hawking his self-driving car gadgetry at an influential San Francisco tech show, the CEO of a Silicon Valley start-up abruptly cancelled its flagship product.

Comma.ai planned to retrofit existing cars with self-driving technology, promising motorists they'd never have to touch their steering wheels or pedals once a US$999 green box called "Comma One" was installed in place of the rear-view mirror.  But the US National Highway and Traffic Safety Administration (NHTSA) sent a letter explaining its mandate of ensuring safety on US roadways, and it needed to ensure the Comma One was not a safety risk before it can be offered for sale.  Regulators insisted that the company simply answer 15 questions about the Comma One regarding its design and safety trials, as well as intended target vehicles and anticipated sales timeline.  Stuff you'd think a company would be happy to brag about.

Comma.ai CEO George Hotz could have been fined US$21,000 a day for failing to comply.  But instead of demonstrating that his product is safe and does what he says, Hotz pulled the plug on the company he started a year ago 2015 after equipping his own Acura ILX with a homemade system that he claimed allowed him to drive autonomously on freeways around the San Francisco Bay Area.

Claiming he'd rather be "building amazing tech than dealing with regulators and lawyers", the 27-year old known for hacking the iPhone claimed that demonstrating his product's safety "isn't worth it".

"Comma.ai will be exploring other products and markets," Hotz tweeted Friday, before adding, "Hello From Shenzhen, China."