Updated October 21, 2021 at 11:40 AM ET
Any new parent will confirm the soothing, somnolent effects of a car on tired, cranky infants.
That road noise works on adults, too. A Hong Kong tour company noticed patrons falling asleep on its buses, and recently launched a five-hour, 47-mile ride to nowhere.
The company, ulu tours, hopes riders will find it a snoozefest.