People who took time off for the Bon summer holidays began returning home Wednesday morning from their hometowns or tourist spots away from the nation's metropolitan areas.
Rail traffic congestion was expected to peak Wednesday afternoon, according to the Japan Railway group, while the Japan Road Traffic Information Center expected extensive traffic jams on expressways across the country around the same time.
At 10:30 a.m., vehicles were backed up 26 km on the Tomei Expressway in Shiga Prefecture, the road center said.
Bullet trains heading for Tokyo were expected to be fully booked for the afternoon, JR companies said.
Japan Airlines Co. said 83 percent of seats were booked on its domestic flights Wednesday to Haneda airport in Tokyo. All Nippon Airways Co. reported a rate of 82 percent.