Roads pose growing danger in poor countries.

Although roads are getting safer in many developed countries, traffic accidents are a rising and underestimated killer worldwide, say researchers who have surveyed dozens of recent traffic studies.

In some developing countries, including China, death rates on roadways have at least tripled in recent decades as new fleets of cars have taken to routes that were already crowded with pedestrians, bicycles, and motorcycles. In other places, missing data rule out precise assessments of the toll.

A comprehensive study blamed 1.2 million deaths and 50 million injuries on road accidents in 2002. High-income European countries had the lowest traffic-related death rates--11.0 deaths annually per 100,000 people--while poorer regions of Africa and the eastern Mediterranean reported annual rates as high as 28.3 deaths per 100,000 people.

Such regional estimates still understate the problem because many countries don't consistently record traffic-related deaths, Shanthi Ameratunga of the University of Auckland in New Zealand and her colleagues say in the May 6 Lancet.

The researchers note that increasing use of speed cameras, vehicle headlights, bicycle helmets, and other measures has reduced the road toll in some places, including the United States and Canada.--B.H.