Ralph Nader on the three types of car crash (0' 38")

Car crashes now claim more than 500,000 deaths a year, and injure another 15 million people. In 100 years there have been more than 20 million car-related deaths worldwide.

Road accidents are the single largest killer of men aged 15-44

The global death toll is set to rise rapidly as developing countries acquire more cars and lorries, and the population of young adults increases.

Road accidents are the single largest killer of men aged between 15 and 44.

In Europe, more than 5,000 people are killed in road accidents each year, and more than 150,000 remain disabled for life. The total number of road deaths in the UK in 1996 was 3,596.

But the number of road accident fatalities in the developed world has been dropping over the last 30 years. Thirty years ago there were more than twice the number of road deaths as today, despite the volume of traffic being less than half what it is now.

Stylish, but maybe fatal

The decline is largely due to a more safety-conscious culture.

It is 15 years since seat-belts became compulsory in Britain, and features such as shatter-proof windscreens, air-bags, crumple zones and collapsible steering columns have made it possible to manufacture safer cars.

But many drivers and passengers continue to eschew seat-belts, and every year thousands of lives are still lost by people who might have survived if they had been wearing them.

How the car industry resisted safety features

Laminated windscreens were introduced in the 1930s, but cars had few safety features

As manufacturers began to make cars that could go faster in the 1930s, the death toll rose. But car producers argued that drivers' safety was not in their hands.

"They explained all traffic deaths and injuries by what was called the 'nut behind the wheel' ideology," said Ralph Nader from the Centre for the Study of Responsive Law.

"It was always the driver's fault - the driver was drunk, or the driver fell asleep, or the driver was incompetent."

The safety of the modern seat-belt was established beyond doubt

When the modern safety belt was invented by Volvo in 1959, other car manufacturers refused to install it on the grounds that it might cut into the passenger's body.

As a law student at Harvard University in the 1960s, Mr Nader came across a series of diagrams showing how seat-belts and other safety features could be incorporated into car manufacturing. He was horrified that car manufacturers were still ignoring the safety recommendations at at time when road deaths were at their peak.

Mr Nader says the manufacturers were driven by profit, and that style and speed could sell more cars than safety features:

Safety diagrams were ignored

"I was stunned. I realised there were a lot of life-saving safety devices like seat-belts and head restraints on the shelf that engineers had built that were never put in cars," he said.

"And I began to ask why. Why were they selling style when they weren't selling safety?

"There was a very simple answer: It focused public attention on crashes, on death."

Mr Nader's anger triggered a chain of events that eventually led to the first comprehensive motor vehicle safety law being passed in the USA in 1967: cars had to meet 22 safety standards covering everything from the steering column to the rear-view mirror. Front seat-belts had to be fitted by law.

Speeding ahead

Road accidents kill 500,000 people a year worldwide

As the car industry has become more safety-conscious, it churns out increasingly powerful vehicles. Cars are now being made with speed limits of up to 170mph.

"That's more than double the national speed limit - it's utterly ridiculous," said David Rodgers of the Royal Society of the Prevention of Accidents.

In the UK at least a third of all road deaths occur when the driver has been going too fast, according to figures collected by the Department of Transport.

Some accidents are attributed to drivers not taking sufficient care because they feel protected by their technologically-advanced cars.