The premise of Old Enough!, a Japanese reality show, is simple. In each 10-minute episode, a tiny kid sets off to complete his first errand alone. With the cameramen. The children totter off into the neighborhood, forget what they're supposed to be doing, and then burst into tears, and then make their way back to Mom and Dad with plastic shopping bags. Hajimete no otsukai, which is based on a children's book of the same name from 1977, has run on Japanese TV for more than 30 years, and some kids on the show have parents who were on it.

In the first episode of the series, a 2-year-old goes to the convenience store to buy groceries for his mom. In the fourth, Yuka crosses a five-lane road to get to the fish market.

If the show were set in the US, the parents would be investigated by child protective services and the children would be in foster care. It would be easy to attribute Hajimete no otsukai to Japanese essentialism. The Japanese are not different from us. They have made policy choices that make it possible for kids to run their first errand a decade before their American counterparts.

In Japan, many kids go to neighborhood schools on their own, that's typical, according to Hironori Kato, a professor of transportation planning at the University of Tokyo. In the show, Japanese children don't run errand for Mom and Dad in the city at 2 or 3 years old, as they do in the show. Children in Japan have an unusual degree of independence from an early age.

Road networks are designed for kids to walk in a safe manner. He said that drivers in Japan are taught to yield to pedestrians. The speed limits are not high. There are lots of intersections in the neighborhoods. Kids have to cross the street a lot, but also keeps drivers going slow, out of self-interest.

The streets are not the same. Many small streets don't have raised sidewalks but depend on pedestrians, cyclists, and drivers to share the road. Curbside parking is rare, which makes it easier to see drivers and pedestrians on the smaller streets of big Japanese cities. I first heard about Hajimete no otsukai from Rebecca Clements, a research fellow at the University of Sydney who has written a thesis on Japan's approach to parking. The show shows how Japan gives children the right to live in the city.

Japanese kids between the ages of 7 and 12 walk for almost four in five trips. A lot of this travel is done by neighborhood schools, which use walking school buses to lead a morning parade of kids. The school trips introduce children to their neighborhood, which can facilitate other kinds of travel.

I asked the professor if it was the built environment or the culture. Policies are built to support that. Japanese cities are built on the idea that every neighborhood should be a village. Shops and small businesses are located in residential neighborhoods, which means there are places for kids to walk to.

In Japan, kids are more likely to travel independently in mixed-use, urbanized neighborhoods. That was in part because destinations were close at hand, but also because children in cities are more likely to see people they know on such trips.

Kidnappings are not uncommon in Japan, even though crime is low by Western standards. The 2012 detective novel Six Four by Hideo Yokoyama was a smash hit in Japan and abroad.

Children are taught to say hello to the people they pass, which is part of the Japanese greeting culture. In Hajimete Episode 7, for example, the local hardware store owner helps Miro cross the street by helping build up a dense social network that can help out in a pinch. In a survey of 14 countries, Japanese parents were the most likely to agree with the idea that neighborhood adults look out for their children.

Mom might be the biggest winner of this system. In the U.S. and Japan, the role of chaperone is usually taken by Mom. Japanese kids make just 15 percent of weekday trips with a parent, compared with 65 percent of American kids, according to Waygood.

That is a cultural difference. We could easily copy it if we wanted to, because it is associated with a different approach to designing cities and neighborhoods.