Friday's ski bus crash in Nagano Prefecture that killed 15 people has raised a slew of fresh challenges for government and industry officials already working to revamp safety measures for long-distance bus services.

While demand for such services is rising with the surge in tourists coming to Japan, a shortage of drivers, whose ranks are also aging, will increase the risks of accidents, industry official say.

In Friday's crash, the bus, which was carrying passengers from Tokyo to the ski resort town of Karuizawa, Nagano Prefecture, rolled over after smashing through a guardrail. The two drivers and 12 university students died at the scene, and another passenger died several days later.