The fatal crash of a chartered bus that killed 15 people and injured 26 others on an overnight tour to a ski resort in Nagano Prefecture last week has exposed structural problems in the industry, including an acute shortage of drivers amid surging demand for discount tours and alleged practices that defy safety rules that were introduced based on the lessons of past accidents. Aside from identifying direct responsibility for the crash, authorities need to investigate the industry's practices to see if passenger safety is being compromised in the tight competition driven by deregulation.

Nearly a week after the accident, which took place in Karuizawa in the wee hours of Jan. 15, it has yet to be determined how the bus with two drivers — both killed in the crash — and carrying 39 passengers plunged off a winding mountain road. It has been reported that the 65-year-old driver behind the wheel at the time of the crash had little previous experience piloting large buses; that the operator of the bus company failed to perform mandatory inspections of the drivers before they departed from Tokyo or give them detailed instructions about the tour route; and that the operator was given administrative penalties two days earlier for failing to have its drivers take regular health exams.

It's unclear whether any of these factors contributed to the nation's worst bus accident in decades. The police probe so far suggests that the driver may have been speeding well beyond the limit and lost control of the vehicle on the twisty downhill road. What should also be investigated is whether the crash is an isolated incident, whether the tour bus industry has properly learned the lessons from past accidents and whether the safety steps taken by authorities are sufficient to deal with the changing conditions of the business.