Half of all people killed each year on the world's highways - more than 600,000 people - are not in cars.
They're pedestrians, bicyclists and motorcyclists. They're called vulnerable road users.
Dr. Emmanual Legard, an injury researcher at the University of Bordeaux in France, explains that they are called that because, unlike occupants of cars, they are not protected by an outside steel frame that would shield them in case of a road traffic accident. So, when a car or truck hits them, they are more likely to be injured or killed.
In Thailand, Legard notes, more than 70 percent of the road traffic deaths are among motorbike users. In Delhi, India, 42 percent of traffic deaths are vulnerable road users.
"This is a problem for the poorer countries because most of the road users are vulnerable road users because cars are much more expensive than bicycles," says Legard.
Problem not limited to developing countries
But in industrialized, richer countries, the numbers of injuries to vulnerable road users are increasing, too. In France, for example, between 1997 and 2007, the proportion of road traffic fatalities for car occupants decreased by 16 percent while it increased by 25 percent among vulnerable road users.
But these official numbers may actually understate the problem.
"The data on vulnerable road users - mortality and morbidity - is underestimated in many countries, including the United States," Legard says, explaining that police do not always count crashes between cars and pedestrians or bicycles as traffic injuries.
According to Legard, alcohol and speed contribute to injuries for the vulnerable road user, but their lack of visibility is also an important factor. Besides increasing visibility by wearing bright clothing and having stricter efforts to reduce drunk driving and decrease speed, another strategy to prevent injuries is through education.
"The vulnerable road user does not obey the traffic rules," he says. "They should be informed of the high traffic injury rates and not be exempt from obeying the traffic laws."
Emmanual Legard's paper appeared on line in the journal PLoS Medicine.