GENEVA (Reuters) - Africa's roads are by far the world's most dangerous with more than 24 in every 100,000 of the continent's population dying on them annually, the World Health Organisation (WHO) said on Thursday.

The Middle East comes next with nearly 18 in every 100,000 losing their lives in traffic incidents each year, according to a report issued to mark the start of the United Nations first Global Road Safety Week.

Worldwide, the report said, nearly 1.2 million men, women and children are killed on the roads every year, and a linked forecast said the figure would double by the year 2020 unless governments took action to improve safety.

While poorer countries are the worst affected, more young people -- nearly 400,000 -- between the ages of 10 and 24 die every year in road incidents than from any other cause, including HIV-AIDS, the WHO added.

"The lack of safety on our roads has become an important obstacle to health and development," said WHO Director-General Margaret Chan in a comment issued with the report. "Our children and young adults are among the most vulnerable."

Chan rejected the use of the term "accidents". "Road traffic crashes are not 'accidents'," she declared. "We need to challenge the notion that they are unavoidable and make room for a pro-active, preventive approach."

In richer countries, where more people can afford cars, death rates are much lower than in Africa and the Middle East, according to the report. The average of deaths in western Europe, the United States and Canada is around 11 per 100,000.

MOST PREDICTABLE

The bulk of fatal road incidents are predictable and preventable, the report said. Many involve children playing on the street who could be given better leisure facilities and young pedestrians who must be better educated about dangers.

The report, "Youth and Road Safety," said some 90 percent of all deaths were in middle-and lower-income countries, where pedestrians, cyclists and motor-cyclists accounted for a majority of the victims, both dead and injured.

A separate U.N. assessment issued before the report said that when surviving victims are not poor to begin with, they and their families are often plunged into poverty by the consequences of their injuries.

"Without collective action, the death toll is predicted to almost double by 2020," said the assessment, emerging from a session of a U.N. Stakeholders Forum on Global Road Safety.

The WHO report said fatal or near-fatal traffic incidents cost an estimated $518 billion globally in material damage, health and other consequences. In some countries the cost is up to 1.5 percent of GNP, more than they receive in foreign development aid.

In richer countries, lowering speed limits, campaigning against drunk driving and enforcing the use of seat belts and motorcycle helmets, as well as creating safe play areas for children, have reduced the number of road deaths and injuries.