Tony Blair and ex-Formula One champion Michael Schumacher have led calls for a world conference to end road deaths.
Michael Schumacher was speaking at UN global road safety week
The prime minister said motor crashes were the planet's second-biggest killer of young men after HIV/Aids.
Mr Schumacher added that the international community needed to wake up to a "horrific waste of life".
A recent World Health Organization report found that nearly 400,000 under-25s are killed in road traffic collisions every year.
The seven-times world champion joined UK road safety groups to launch the Make Roads Safe campaign for a global United Nations conference on the issue.
HUMAN COST OF ROAD CRASHES
1.2 million killed each year around the world
66,000 seriously injured globally each day
70 British children killed or seriously injured each week
Source: World Health Organization
It is estimated that road traffic crashes cause 1.2 million deaths every year, including those of 1,000 young people every day.
Each week 70 children are killed or seriously injured in the UK.
Mr Blair made his remarks in a video statement for UN global road safety week in London.
He said: "Every minute of every day a child is killed or seriously injured on the world's roads.
"Road crashes are the second leading cause of death for young men after HIV/Aids, and in some African countries more than 70% of those killed on the roads are young breadwinners.
"It is becoming clear that road injury has a serious impact on the wider development goals we are all trying to achieve."
Mr Schumacher said: "Road crashes kill on the scale of malaria or tuberculosis, yet the international community has not woken up to this horrific waste of life.
"That is why I strongly support the Make Roads Safe campaign and the proposal that the United Nations organise a first ever UN ministerial conference to tackle this preventable loss of life."
Edmund King, executive director of the RAC Foundation and a co-ordinator of the Make Roads Safe campaign, said that half of all children killed or seriously injured on the roads in England come from deprived areas.
"The road safety community in the UK is united behind the call for a UN global ministerial conference to give urgently-needed direction to road injury prevention."