One microsleep warning sign occurs when you catch yourself leaning blank in the drivers seat

The answer is Forward.

One microsleep warning sign occurs when you catch yourself leaning Forward in the drivers sea. Microsleeping while driving is surprisingly common and according to surveys, at least 10 percent admitted to having slept briefly while at the wheel. A person is likely to fall asleep when he or she is the driver of the vehicle and may likely lean forward because the individual does not have anything to lean on but only the steering wheel.