Tokyo 2020 Olympic games emblem is displayed at Tokyo Metropolitan Government Building on June 15. (Toru Hanai/Reuters)

Rio de Janeiro has some famously tough hurdles to overcome in staging the Summer Olympics next month: rising crime, polluted sailing venues, an unfinished subway line and, most famously, the Zika virus in a city packed with athletes of childbearing age.

But look on the bright side: There will be another Summer Games in 2020, this one in Tokyo, where new technology may benefit not only the competitors but also the city they leave behind. Japan has done this before, Heather Hansman points out in Popular Science magazine: For the 1964 Olympics, it completed the bullet train, which revolutionized Japan’s national transportation.

Hansman points out a few of the highlights:

●Field tests have begun on driverless taxis that can be hailed by cellphone to take athletes and spectators around the Games. “The technology still needs some tweaks,” she writes, “like teaching the software to read maps.”

● Tokyo is putting $367 million into hydrogen-fuel-cell cars and refueling stations for the Games; what’s more, the 6,000-unit Olympic Village is designed to use power exclusively from such fuel cells. It’s an expensive, investment, but the city hopes that after the Games are over, “the village will be an environmentally friendly residential district powered by a next-generation hydrogen system.”

Yoshiro Mori, Japan's former prime minister and president of the Tokyo 2020 Organizing Committee of Olympic and Paralympic games, delivers a speech on July 3 during a send-off ceremony for the Japanese team's departure to the Rio 2016 Olympic Games. (Issei Kato/Reuters)

●With competitors and spectators flying in from around the world, Boeing and All Nippon Airways are among companies investigating biofuel-powered aircraft to reduce the Games’ carbon footprint. Planes need a lot of fuel, and biofuels need a lot of plant mass, so companies are working on giant farms and algae pools to get the green stuff growing.

●Olympic Broadcasting Services plans to shoot the Tokyo Games in 8K UHD — that is, at about 16 times the resolution of today’s high-def TV. This branch of the International Olympic Committee will do a trial run in Rio, shooting 130 hours of the festivities.

●And there might be holograms! It’s very sketchy, but Mitsubishi Electric says it has devised a way to create a floating 3-D image you can walk around (as opposed to the kind you may have seen projected in front of a screen). Olympics organizers are considering using it for posting information — it could be like a floating, semi-transparent person who tells you when the synchronized swimming finals begin.