One night, leaving the Palaceside Building east "Hitotsubashi gate" to cross Hakusan-dori, we met a cluster of low "go-kart"-like machines coming from Jimbocho toward the Imperial Palace =photo above. The shot has the Marubeni site and expressway behind.
These are the "street karts" rumored popular with inbound visitors. Indeed the riders looked like Asian tourists.
Street karts resemble amusement-park go-karts: low bodies, no cover, engines exposed. Displacement 20–50 cc, legal top speed 60 km/h; under the Road Traffic Act they are "automobiles (minicars)" and may use ordinary roads like cars. An ordinary license is enough; foreigners with an international permit are OK.
Easier than renting a car, and perhaps because you see the city from a lower eye line than a passenger car, they are popular with foreign visitors. Word likely spreads on Instagram and other SNS. Costume like character suits is said to be the "rule." Look closely at the photo above — they are wearing something. The leader is probably the guide; he looks leaned back but seems to be photographing the guests behind while waiting at a light.
The Mainichi March 4 Tokyo edition had "Use growing in Tokyo — 86% of accidents involve foreigners"; the Asahi August 23 evening social page ran "We rode in Tokyo — wind pressure, a scare changing lanes / fresh views, pleasant." Those say street-kart operators appeared in Tokyo from 2013; now 10 shops, six opened last year — rapid growth.
Accidents are rising too. Police say 749 "minicar" accidents nationwide in the decade 2008–2017, growing yearly and in the 80s each year since 2015. Accidents by foreign visitors stand out: at least 68 in Tokyo from last March through this June, 60 involving foreigners. MLIT will from April 2020 require rental operators to fit seat belts even on existing vehicles, among other safety steps.
Further, the Nikkei September 28 morning social page said Nintendo sued rental operators for unauthorized use of game characters such as Mario on kart costumes as copyright infringement; the Tokyo District Court ordered a halt to costume lending and 10 million yen in damages.
We half want to try, yet it looks scary. The Asahi piece: "What you feel is the low height.... Body exposed, you feel the wind of cars crossing. Changing lanes, sweat at the thought of contact.... I thought I was going fast but the meter said 40 km/h. Some feel two or three times usual speed."
No steel plate to protect you — literally life on the line. We will skip the ride and just watch them in the streets.