SAE J3016 Level 2 automation requires more attention than driving a vehicle without any automation, because the driver needs to pay the same amount of attention to the road as any other driver, as well as monitor the automation to be able to intervene without notice.
Normal freeway driving involves missing barriers by only a few feet, so it may not even be physically possible for a human to intervene, once its clear that the cars path will intersect the barrier. For example, in the fatal 2018 crash of a Tesla Model X in Mountain View (https://news.ycombinator.com/item?id=22305488) the car crashed into a divider between the offramp and the freeway lane from which the offramp departed.
