carpolepsy
the uncanny ability for some passengers to fall asleep in the car almost immediately after the engine starts.
Road trips with Mike are like road trips by myself. As soon as he gets in the car, the carpolepsy hits and he's out.
Carpolepsy
The act of always falling asleep or getting extremely tired when riding passenger in a car.
Everytime my girlfriend goes on long car rides she gets carpolepsy. She always falls asleep.