A tour bus fell off a road to a grassy area a few meters below on Japan's northernmost main island of Hokkaido on Friday, leaving about 30 people injured, including at least two seriously, police and a hospital said.

The injured were among 46 passengers and three crew members who were on a four-day tour of Hokkaido from Tokyo and nearby prefectures. The driver has told the police that he got spacey and took his eyes off the road when the bus veered off the road around 3:45 p.m.

The bus left from a city adjacent to Sapporo earlier in the day -- the second day of the tour -- and was planning to head to a hotel near the Lake Akan hot springs resort area after visiting some other locations. The accident occurred when the bus was passing the town of Shimizu.

The bus was trying to enter a rest stop just before the accident, the police said. According to bus operator Abashiri Kanko Kotsu Co. and other sources, the driver was 58-year-old Yasushi Ando who has driven buses for about 20 years.

Ando had been off duty for three days until Monday and was assigned to a different three-day tour from Tuesday to Thursday. He then took an afternoon off before returning to work Friday, according to the bus operator.

The police said another bus operated by Abashiri Kanko Kotsu had caused an accident in Kushiro, Hokkaido, on July 30, in which six people were injured.

In Shimizu, where the tour bus veered off the road and flipped over, a resident wondered how the accident occurred on "a straight road with a good view."

"I can hardly imagine why the bus fell off the road," the 29-year-old company worker said. The accident site is not in an area with heavy traffic, according to a town official.

Local rescue workers said they were notified that "a bus fell about 5 meters" from the road. A total of some 40 people were taken to hospital, including one passenger who was transported by helicopter.