Why hasn't the autonomous car revolution happened yet? A few years ago industry figures were predicting driverless cars would take over our roads by the end of the 2010s, but so far there's no sign of them. Justin Rowlatt speaks to Oliver Cameron from Cruise - a company testing driverless cars on the streets of San Francisco, and to industry analyst Sam Abuelsamid from Guidehouse Insights about the technological and regulatory challenges that still exist. UK transport minister Rachel Maclean explains why governments are enthusiastic about the technology, but need to put safety first.

(Photo: An autonous Cruise car on the streets of San Francisco. Credit: Getty Images)