German chemicals giant BASF is, apparently, hard at work developing special paint to stop autonomous cars crashing into each other.

It’s to do with lidar, a sensor that uses reflected laser beams to draw a highly detailed 3D picture of whatever happens to be in the car's way.

Expensive and often bulky roof-mounted lidar is widely used in autonomous car development. It isn’t yet common as part of production cars’ advanced driver assistance systems (ADAS), but it's set to become quite a big deal (although Tesla boss Elon Musk may disagree).

It turns out, however, that the darker shades of paint preferred by many car buyers don’t reflect lidar very well, which is a problem that BASF is setting out to address (the ins and outs of how the new paint works are about as interesting as watching it dry, but ).

Lidar-absorbing paint is just one of hundreds, perhaps thousands, of hurdles in the way of self-driving cars, delaying the arrival of full autonomy for some years to come. Many car makers have been quietly back-peddling on their claims of a few years ago that they would have fully autonomous cars on the road by, well, about now.