"When an accident happens, consumers naturally shy away from taking the next bus, train, plane or whatever. But it's not long before bookings return to normal or near-normal," said one travel industry executive, who like other industry figures contacted for this article did not want to be identified.
The initial impact on consumer behaviour can be spectacular, as it was in the case of the Herald of Free Enterprise, the P&O ferry that capsized off Zeebrugge with the loss of 187 lives in 1987. The following year cross- channel car traffic fell by 10 per cent, and coach traffic dropped by nearly a fifth, according to figures from the Port of Dover (see graph). But in 1989 consumers returned in much greater numbers, resuming the upward trend in cross-channel traffic.
Other modes of transport have proven more resilient, showing no evidence of decreased use, particularly if there is little in the way of an alternative. For instance, the number of passengers travelling on London Underground reached an all- time high in 1988, the year following the the King's Cross tube station fire in which 30 people died. Nor did the Clapham rail disaster deter people from using the railways - a record number took the train the following year.
Likewise, the crash of Pan Am 103 at Lockerbie in 1987 had little impact on the general transatlantic air travel market, which also showed increased usage the following year. However, the disaster - in which 270 people perished - caused Pan Am's bookings to drop by a quarter in the immediate aftermath although they returned to near-normal levels within months.
More recently, the Valujet crash in Florida caused bookings on similar low-cost carriers to fall by between 10 per cent and 20 per cent, and caused both Valujet and another small carrier, Kiwi Air, to seek bankruptcy protection.
"People don't lose confidence in the airline system itself, just elements of it," said one airline executive. "And they have very short memories." The executive added that if accidents involve little or no loss of life, they are forgotten even more quickly. "Everyone searches for closure in an accident, and if funerals, inquiries and compensation claims go on for years afterwards, they will only serve as reminders of the tragedy."
Travel industry experts agree that if consumers see an incident as an isolated case, and not part of a pattern, they will not alter their buying habits for long. But if a second or a third similar incident occurs, and a pattern starts to emerge, confidence in the product drains away.
In 1994, USAir encountered this problem when two of its planes crashed in different circumstances. After the first accident, bookings fell slightly; after the second, they fell much further.