Why is it easier for babies to fall asleep in the car?

Babies find it easier to fall asleep in the car due to the combination of factors such as the rocking motion, sedentary environment, lack of engagement in the back seat, sound, motion, and setting. The rocking motion, constant motion of the car, and low rumble of the engine[2] can make them feel secure and cozy, similar to the movement of the uterus. The car seat can also feel secure like a swaddle, and the scenery inside the car provides a calming, familiar environment for sleep. Infants need a lot of sleep and it's likely that nap time will coincide with a car trip[1], making it easier for them to fall asleep[1].