A self-driving car owned by Apple was involved in an accident, California’s road authority has confirmed.

The car, a modified Lexus RX450h with autonomous sensors, was rear-ended by a human driver in a Nissan Leaf.

Humans were unhurt, but the machines suffered moderate damage.

Apple’s car is understood to be part of an ambitious but secretive programme - Project Titan. Apple has not commented on the 24 August collision, understood to be the company's first.

Speculation as to what the project seeks to achieve ranges from a fully-fledged Apple car - or just working with existing car makers to provide autonomous technology.

Apple’s self-driving programme had been public knowledge, It was revealed that the company now has 66 such cars on the roads, with 111 drivers registered to operate them.

Like every firm experimenting with autonomy in California, Apple must provide regular reports to the state’s Department of Motor Vehicles (DMV), including when a crash occurs.

'Waiting for a safe gap'

According to documents released by the DMV on Friday, Apple’s car was on the roads in Sunnyvale, a Silicon Valley city not far from Apple’s headquarters in Cupertino.

The crash happened just before 15:00 - it was dry, clear and there were no unusual conditions, the DMV said.

“An Apple test vehicle in autonomous mode was rear-ended while preparing to merge onto Lawrence Expressway South from Kifer Road,” the incident description reads.

“The Apple test vehicle was travelling less than 1mph waiting for a safe gap to complete the merge when a 2016 Nissan Leaf contacted the Apple test vehicle at approximately 15mph.

"Both vehicles sustained damage and no injuries were reported by either party.”

The DMV does not attribute blame in its reports. Self-driving cars being rear-ended, however, might be considered a trend.

A recent report by investigative technology news site The Information revealed teething problems at Waymo, the self-driving car company spun out of Google, where there have been headaches caused by what humans might consider over-cautious driving.

The self-driving cars would stop abruptly in scenarios where humans might zip through, such as turning across a line of traffic.

"As a result, human drivers from time to time have rear-ended the Waymo vans,” the report noted.