I am unaware of the specifics, but the law says " Since DDAW systems assess the physical state of the driver through indirect means, it is not possible to fully test those systems through a set of defined tests or with a programmable machine, which reproduces human behaviour.

..

The vehicle manufacturer carries out validation tests with human participants, either in a simulated environment or in a test vehicle, and present to the approval authorities"

So it sounds like they left it vague enough for manufactures to do their own thing.