Taxi accidents involving fatalities and serious injuries have decreased by about 40 percent after taxi firms belonging to an Osaka-based mutual aid association were required to mount video cameras in their taxis to record accidents, The Yomiuri Shimbun learned Tuesday.

The association, to which about 100 taxi firms--about half of those in Osaka Prefecture--belong, believes the cameras have caused drivers to be more cautious as the device can precisely record how accidents occur and who is at fault.

Taxi firms in the prefecture have been in fierce competition since the industry was deregulated in February 2002. Taxi accidents resulting in injury or death had increased for nine consecutive years, and the increased competition had been partly blamed for the trend.

The Osaka prefectural police had said the device would be very effective in preventing accidents.

The five-centimeter-long, 15-centimeter-wide and three-centimeter-thick box contains a camcorder and is mounted inside the front windshield. When the 70,000 yen device senses a jolt caused by sudden braking or an accident, it is capable of saving 18-seconds of front-view video footage before and after the jolt.

An association spokesman said: "We believe the whole taxi industry should introduce the device to curb accidents. It costs money, but it pays off."

In March, the association, which handles accidents involving member taxis, purchased the devices for its accident compensation negotiations. The association has loaned 7,700 devices to member firms free of charge.

As a result, the number of accidents per 1,000 taxis was 9.9 from April to November last year, down 12 percent from the same period the previous year.

Fifty-two accidents resulting in serious injury or death occurred over the same eight month-period last year, down from 73 over the same period the previous year, a decrease of 39 percent.

According to the police, taxi accidents causing death or injury that are the fault of the taxi driver have consistently increased since 1996, reaching a record high of 2,719 in 2005.

In 2002, the Road Transport Law was revised, no longer requiring taxi firms to have a government license and only requiring registration. Since then, taxis in the prefecture have increased by 2,000 to about 22,700--the highest growth rate in the country during the 3-1/2-year period.

An official of the Road Transport Bureau's safety office at the Construction and Transport Ministry said: "We're also studying whether the device really reduces accidents, but it seems to have been proven. So we want to discuss how to promote the device, including publicizing how it can reduce compensation fees [due to accidents]."