Western governments are being urged to increase the amount of aid for reducing road accidents around the world.
Campaigners say the numbers killed equate to a "third world war"
The Commission for Global Road Safety says the problem, which kills 1.2m a year, is a "global epidemic", on a par with malaria and tuberculosis.
Failure to halt the number of road deaths could jeopardise key development goals, it says.
The Commission will present its findings to world leaders ahead of the G8 summit in St Petersburg in July.
The Commission's chairman, former Nato chief Lord Robertson, said global road safety needed to be on the agenda at future G8 summits.
1.2m people killed each year
50m people injured each year
500 children killed each day
85% of casualties in low and middle-income countries
Road deaths to double by 2020 in these countries
"In 2005, millions of people and the leaders of the G8 responded to the call to Make Poverty History. Yet many of the gains for development...will be at risk if action is not taken to reverse the growing epidemic of road traffic death and injury, with its terrible human and economic cost."
Lord Robertson said "political leadership" from G8 members and a "significant increase in resources" were needed to make roads safer.
The findings have been published in a report, Make Roads Safe, released in London on Thursday.
Formula One driver Michael Schumacher, a member of the Commission, has given his backing to improved road safety.
"We need to make people aware of the real human cost of road traffic injuries across the developing world. Five hundred children are dying every day and thousands more are being disabled or injured," he said.
The report says more young men die on the roads than have died in recent wars - and only HIV and Aids take more lives.