A new report from the World Health Organization suggests we’ve made some progress in reducing traffic fatalities through seat belt laws, improved highway and vehicle design, and campaigns to reduce drunk or drug-impaired driving.

But motorcycles are bucking the trend, even in the world’s wealthiest and most developed countries, including the United States.

Any guesses on what legislative body is arguably most responsible for the increase in the United States?

The WHO report says more than 1.2 million people die in traffic crashes each year, with developing or undeveloped countries bearing by far the heaviest burden. Africa has the highest traffic fatality rate, Europe the lowest. Worldwide, the people who die most often are pedestrians, bicyclists and motorcycle riders. They often are also young, usually between the ages of 15 and 29. For this age group, traffic deaths outnumber others such as suicide, HIV/AIDs and homicide.

Yet, despite a 4 percent rise in global population and a 16 percent jump in the number of motorized vehicles, the overall rate of traffic fatalities leveled off between 2007 and 2013, the WHO report says.

But the report also notes an alarming increase in traffic deaths among motorcyclists in our hemisphere. The report says that although the proportion of motorcycle deaths stayed the same in most regions of the world over the three-year period, it rose by 15 to 20 percent in the Americas. The report attributes this increase to the growing number of people who now ride motorcycles.

But there’s also more to it than that. The WHO report tracks similar research cited by the National Safety Council that show motorcycle deaths increased by 8 percent in 2016 compared with the previous year.

Deborah A. P. Hersman, the council’s president and chief executive, traced the increase to the lack of mandatory helmet laws in the United States. The National Conference of State Legislatures  says that in states lacking a mandatory helmet law, 58 percent of motorcyclists killed in 2015 weren’t wearing helmets, compared to 8 percent in states with such laws. Hersman called on states to institute – or in some cases, reinstitute – laws that require all motorcycle riders to wear a helmet.

“I would say we’ve just become complacent,” Hersman told reporters last week, referring to the collective failure of the United States to take steps to combat a number of behaviors that push traffic fatalities higher.

Back in 1975, every state except California required motorcyclists to wear helmets, at least in part because of federal incentives, according to the 2016 research published in BMC Public Health. The study also found that injured motorcyclists who failed to wear helmets cost an additional $290 million in national health care costs.

Since 1966, Congress began tying federal highway funds to the passage of such laws. By 1995, however, Congress walked away from any such incentive, and several states, such as Arkansas and Texas, moved to repeal their helmet laws.

Today, only 19 states and the District of Columbia require all motorcycle operators to wear a helmet, the NCSL blog says. Other jurisdictions require only some, such as younger riders, to wear helmets. Three states – Illinois, Iowa and New Hampshire – have no helmet requirement at all, the NCSL says.

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