The hard job of teaching autonomous cars to drive

WHEN DRIVINGAI,, Clara-Marina Martinez makes a note of any unusual behaviour she sees on the road. She then feeds these into machine-learning algorithms, a form of which she is helping develop for Porsche Engineering, a division of the eponymous German sports-car company.Those algorithms are intended to produce a system reliable enough for a car to drive itself. Such a fully autonomous car, known in the industry as Level 5, should be able to complete an entire journey without any intervention from the driver, and cope with all situations on the road. But this is proving hard to achieve, and many attempts to do so are being scaled back. Last year, for instance, Uber, a ride-hailing service, sold off its unit developing self-driving cars.