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.
"When we were brainstorming new tours, I saw a social media post from my friend saying that he was stressed out by his work, he couldn't sleep at night," Kenneth Kong, ulu's marketing and business manager told the Associated Press. "But when he was traveling on the bus, he was able to sleep well. His post inspired us to create this tour that lets passengers just sleep on the bus."
Tickets range from $13 to $51 per person, depending on upper or lower deck seating. Riders also get a goodie bag with an eye mask and earplugs.
The first ride launched Saturday and sold out. Some inaugural passengers even brought their own blankets and slippers.