Photo/Illutration A billboard truck with a non-Tokyo license plate advertises an idol group in Shibuya Ward on April 30. (Shin Kasahara)

Nine local governments in the greater Tokyo area are joining forces to close a loophole that allows trucks to enter the capital flashing obnoxious or dangerously distractive advertisements on their sides.

The Tokyo metropolitan government in 2011 revised an ordinance to require billboard trucks to gain approval for their designs from the Tokyo Outdoor Advertising Association, a public interest organization.

The mobile advertisements must not make the public feel anxious or uncomfortable. They also must neither distract the attention of other drivers nor use vibrant, primary or gold and silver colors excessively.

Violators are fined a maximum 300,000 yen ($2,210).

However, the regulations are applicable only to vehicles with Tokyo license plates.

When the metropolitan government conducted a survey in downtown areas in Shinjuku and Shibuya wards in February, all 74 ad trucks seen had non-Tokyo license plates.

In about one hour one evening in late April, 26 billboard trucks ran through famous scramble crossing in Shibuya.

They blared out messages to recruit staff for sex parlors, promote a concert for an idol group and announce other products or services.

All trucks had non-Tokyo license plates, including 10 issued in Yokohama, 11 in Noda in Chiba Prefecture, and five in the Owari-Komaki region of Aichi Prefecture.

A 66-year-old driver of an ad truck with an Owari-Komaki plate, who was on a break, said he is instructed to take several routes in Tokyo, including ones going through the Shinjuku, Ikebukuro and Ueno districts.

He said the truck is owned by an ad firm in Aichi Prefecture, and he usually drives for about six hours a day.

I understand there is a loophole in the regulations,” he said. “But I don’t speed, and I have no intention of being a nuisance.”

However, the metropolitan government views these “intruder” ad trucks as a major problem that can lead to accidents and ruin the cityscape, officials said.

The metropolitan government in April hosted a meeting attended by the governors of Tokyo, Kanagawa, Saitama and Chiba prefectures, as well leaders of five major cities in the three prefectures.

They agreed to set up a panel to consider unified regulations on the ad trucks.

“We need to work together and take measures to create good cityscapes and prevent harm,” Tokyo Governor Yuriko Koike said.