Convoys of go-karts reminiscent of Nintendo Co.’s “Mario Kart” video game series have been turning heads in Tokyo’s traffic, but the rental companies behind them, which cater mostly to foreign tourists, are facing growing scrutiny over their safety records.

Tourists dressed as Mario and other characters from the video game drive through often-crowded public streets in the low-riding vehicles.

Although they are operated in line with the law, the central government has raised concerns about the lack of safety measures being taken by five Tokyo-based operators following a spike in go-kart accidents in recent months.

On a cool evening in mid-June, this reporter witnessed four Australians in their 20s riding go-karts. A man in the group said: “My wife checked it out, and we have seen various YouTube videos. They looked fun.”

During their tour, two of the group’s vehicles got into minor collisions near an intersection in Roppongi, the famous nighttime hub and one of the most heavily congested areas in central Tokyo.

The two go-karts, which had crashed into and slid atop one another, disrupted traffic at the center of the three-lane street for a few minutes before they were disentangled by the two female drivers.

In the Odaiba waterfront district, another popular sightseeing destination, some drivers in a group of six ran a red light so they could catch up with the carts ahead, prompting a warning from the tour guide to follow the traffic rules.

In late May, the Metropolitan Police Department urged the five go-kart operators to strengthen their safety measures.

The request, which is by no means binding, includes providing customers with a thorough explanation of the local traffic rules and encouraging drivers to wear helmets and other protective gear.

The police are also asking the operators to properly check the drivers’ licenses, get them to obey the traffic lights, demand they not drive erratically or get out of their vehicles to take photos while stopped at traffic lights, and ensure proper parking.

Perhaps the biggest concern is visibility, since the go-karts hug the ground. Trucks in particular are being warned to keep a healthy distance behind to avoid inadvertently dragging the go-karts when making turns at intersections.

One of the five companies, EcoKart L.L.C., in Higashiazabu in Minato Ward, did not appear overly concerned about implementing the requested safety measures, even after receiving a written request from the police in coordination with the transport ministry.

Although a man with the Australian group had failed to get an international driver’s license before visiting Japan, an employee told him he would still be permitted to rent a go-kart as long as he was willing to assume responsibility if stopped by the police. The man decided against renting the vehicle.

The basic explanation of the rules provided before a drive takes less than 10 minutes. Drivers are shown how to adjust their seats, start and stop the go-karts, accelerate, brake, signal and use their parking brakes.

The guide, who was the lead driver of the six vehicles, appeared to be provoking the drivers into imitating his maneuvers while driving erratically in Odaiba. He then asked the drivers to park on the street for a 10-minute break in the two-hour ride.

The rental companies are believed to be taking advantage of traffic loopholes. Because go-karts are subject to conflicting traffic and safety laws — falling into a legal gray area between cars and scooters — drivers can avoid wearing helmets or seatbelts while driving at speeds up to 60 kph.

EcoKart’s guide describes the company as a “kind of an affiliate or franchise” of Shinagawa Kart L.L.P., another one of the five firms the police have asked to take further safety steps.

Shinagawa Kart manages over 100 go-karts for rental, compared to only a dozen for EcoKart, according to the guide. But the Shinagawa outlet, which says in its guide that it does not hire Japanese employees, accepts only foreign customers. Japanese customers are requested to make bookings at the shop in Higashiazabu.

Yusuke Yamazaki, the de facto head of the Shinagawa shop, and MariCar Inc., for which Yamazaki is the president, were sued at a lower court in Tokyo in late February by Nintendo over the alleged use of characters created by the Kyoto-based video game and console maker and acts of unfair competition.

Nintendo had received a complaint from residents over traffic violations around areas where the go-karts are rented.

Yamazaki also works for several other operators in some of Japan’s major tourist draws, including Tokyo, Osaka and the town of Fujikawaguchiko at the foot of Mount Fuji, as well as Okinawa, according to their registries and court documents.

Costumed tourists riding go-karts in Tokyo have become a common sight, with many videos uploaded on the internet.

The go-kart group, which counts foreign tourists as making up around 95 percent of its customers, has estimated annual sales of at least ¥250 million ($2.2 million). This has grown since MariCar was established in June 2015, a court document showed.

The defendants have argued MariCar is a separate entity that merely sells go-karts and provides maintenance services to the operators. The registries, however, show MariCar and the operators to be closely linked.

MariCar’s Yamazaki had not responded to an interview request from Kyodo News by the time of this printing.

Amid rising safety concerns over the go-karts on public roads, Land, Infrastructure, Transport and Tourism Minister Keiichi Ishii said in late May that four fatal microcar accidents occurred on public roads between 2012 and 2016.

In 2016, 88 traffic accidents occurred in which drivers of microcars such as go-karts were to blame, according to the ministry.

Ishii also said traffic experts were set to begin discussing safety steps for microcars in June, apparently referring to go-karts.

But the Institute for Traffic Accident Research and Data Analysis, the organization Ishii was referring to, had yet to conduct any research or analysis on the matter as of late June, its spokeswoman said.

Asked about further legal steps, a spokesman at the Metropolitan Police Department said, “Nothing has been decided on any action to take against the operators at present.”

The insurance payout for an injured go-kart driver is ¥3 million (about $26,300), with a ¥50,000 deductible — money paid out of pocket before the insurance kicks in.

While the colorful go-kart convoys are a welcome spectacle for many residents, concerns about their safety appear, until now, to have been largely swept under the rug.