Photo/Illutration A green guide line for automobiles is put in place along the Keinawa Expressway in Kinokawa, Wakayama Prefecture. This photo was taken on Nov. 22. (Kazuhiko Matsunaga)

An unfamiliar green line appeared along a short stretch of the Keinawa Expressway, a 120-kilometer-long motorway straddling Kyoto, Nara and Wakayama prefectures, in late November.

The mark runs slightly to the right of the middle of each lane and its off-center position may puzzle motorists.

Traveling down this section of road, some drivers seemed to feel awkward and confused. They attempted clumsily to align their cars’ wheels to one side with the line or stay left of the marking.

However, this line was put in place on a trial basis to prevent traffic accidents.

The green line sits on a 4.5-kilometer section of road between the Kinokawa-Higashi interchange and the Kinokawa interchange in Wakayama Prefecture. It was installed by the Wakayama Office of River and National Highway.

According to the developer’s accounts, lanes on roads for which the office is responsible are not equipped with central barriers made of concrete and other hard materials.

To prevent head-on collisions and other serious accidents, a protective fence using wire ropes had been set up by fiscal 2022 along a 23-km stretch of the office’s 41-km service area.

The protection has proven effective. No head-on collisions were reported in fiscal 2022 following the fence’s incorporation.

However, a challenge remained. Motorists came into contact with the fence on no fewer than 99 occasions.

These accidents caused damage to the protective fence, leading repeatedly to the temporary closure of the road for repair work at night.

With this in mind, the green line in question, called a “vehicle guide line,” was added as a “savior to deter accidents.”

The highway office explained that people in right-hand-drive vehicles are supposed to drive with the green line always just below the driver’s seat.

Yellow signs have been put up by the expressway, too, to inform drivers of where the guide mark is and how one is expected to drive in the designated zone.

VISUAL GUIDANCE FOR DRIVERS

The first guide line of this sort in Japan appeared on the lanes of a 6-km strip along the Akita Expressway between the Takanosu interchange and the Niidamanaka interchange.

The Noshiro Office of River and National Highway, which oversees the area’s management, said it added the line in May as part of a test following the advice of Hidekatsu Hamaoka, a traffic engineering professor at Akita University.

The line runs right beneath the driver’s seat to help motorists be better aware of their lane position.

This is why the guidance line is located off-center.

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A vehicle runs in the correct manner suggested by the Wakayama Office of River and National Highway. (Provided by the Wakayama Office of River and National Highway)

Since the only other guide line of this type runs between the Nikaho interchange and the Ouchi junction on the Nihonkai-Tohoku Expressway, the one in Wakayama is the first of its kind in western Japan.

The effectiveness of the green line has yet to be verified since the marking method has been put to work only recently. However, a representative at the Wakayama office has high hopes.

“The green line will serve as a visual guide to lessen the number of crashes into the defensive fence,” the official stated.

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