Autonomous driving is probably the leading generator of auto industry jargon, and none has been more difficult to pin down than L2+.
L2, for level two, is at least reasonably widely known for indicating the stage of autonomy on a scale of zero to five as defined by the Society of Automotive Engineers (SAE). Level three is when the car takes control, however brief, so L2 is the highest level of assisted driving before you hit true autonomy.
But then came L2+. It’s not an SAE accepted term, but one that has been increasingly touted by car makers in recent months as they temper their once bold predictions of full autonomy and start becoming realistic about what’s possible within a medium-term timeframe. VW Group boss Oliver Blume even referred to L2++ in a recent investor call, further muddying the waters.
The Plus part has come to generally refer to driving with hands off the wheel, but with eyes on and brain engaged. In the broadest definition the car is controlling the driving functions, ranging from following a mapped route, to making lane changes and modulating speed in traffic. The driver can drop their hands but remains ‘in the loop’, to use the jargon, with eye-trackers checking they really are paying attention. It’s also illegal, at least in Europe and the UK.
Regulation No 79 from the Economic Commission for Europe of the United Nations (UNECE), the body that sets the homologation rulebook in the region (and isn’t a function of the European Union), states that drivers must have their hands on the wheel. No one, not even Tesla, has sought to bypass that.
However, the UNECE is in the process of drafting new regulations to allow hands off, and Matthew Avery, director of research at UK safety testing body Thatcham, reckons it could be law by 2024.
Of course, Level 3, where you can not only take your hands off but also cede control to the car in certain conditions, is allowed by the UNECE regulations, specifically regulation 157 Aux. But so far only Mercedes, for the S-Class and EQS, has sought to homologate a system.