The number of pedestrians killed in accidents involving SUVs has skyrocketed by 81 percent in the last decade, according to a new report released by the Insurance Institute for Highway Safety.

After a decade of decline, highway deaths have been rising in recent years. All sorts of factors appear to be playing a role, including higher speed limits and distracted driving, according to safety experts — but the IIHS report points towards the rapidly growing number of SUVs on the road, suggesting that their design could make them more deadly in a vehicle-pedestrian crash than regular cars.

“SUVs have higher front ends, and often the design for the vehicle is much more vertical than passenger cars,” said IIHS President David Harkey, something that can make for a more blunt impact and less likelihood that a pedestrian being struck by an SUV might be able to roll off the vehicle and reduce injuries.

All told, pedestrian fatalities have climbed to nearly 6,000 a year, according to data from the National Highway Traffic Safety Administration, a roughly 50 percent increase since 2009.

The figures can be a bit misleading, however. Over the past decade, sales of all light trucks has also soared, collectively make up about two-thirds of the U.S. new vehicle market. SUVs alone now represent more than half of all sales. But that growth doesn’t account for the fact that pedestrians are simply less likely to survive being hit by a utility vehicle.

With smartphones now all but ubiquitous, the NHTSA blamed distracted driving for roughly one in 10 of all highway deaths. It's also linked to the rise in pedestrian fatalities, in particular, because both drivers and those on foot may lose sight of what’s happening when they’re lost in e-mail or texting.

"We’ve got distracted drivers and we’ve got distracted pedestrians, and that is a deadly combination," Rebecca Lindland, a Kelley Blue Book auto analyst, noted in a statement, when 2017 pedestrian fatality statistics were released recently.

While the improper use of smartphones and other consumer electronic devices may be contributing to pedestrian and other fatal highway crashes, automakers are hoping to use other forms of technology to make roadways safer. A growing number of vehicles are now equipped with forward collision warning systems that can predict a potential crash and alert the driver to apply the brakes. More advanced versions also can hit the brakes automatically if the driver doesn’t immediately respond.

"We’ve got distracted drivers and we’ve got distracted pedestrians, and that is a deadly combination."

Volvo was the first to add an additional level of protection with its City Safety system being programmed to detect pedestrians and, on some models, even bicycles. Ironically, when a Volvo SUV modified by Uber to drive autonomously was involved in a fatal pedestrian crash near Phoenix in March, the automaker subsequently said that its built-in pedestrian detection system had been disabled but likely could have either prevented or reduced the severity of the incident.

Similar pedestrian detection systems have been added by a number of manufacturers and have moved down-market from luxury brands to mainstream makers such as Hyundai, which has introduced the technology on its new Kona SUV.

But as the recent fatal crash in Arizona showed, high-tech solutions don’t always work. Some cities, such as Honolulu, have begun to crack down not just on distracted drivers, but also on pedestrians who walk into intersections while staring at their mobile devices.

Safety experts are looking at some other potential explanations for rising pedestrian fatalities. A report released earlier this year by the Governors Highway Safety Association noted that in seven states and the District of Columbia where recreational use of marijuana has been legalized, there has been a sharp increase in pedestrian deaths.

“We are not making a definitive, cause-and-effect link to marijuana,” the study’s author, Richard Retting, told the New York Times. Nonetheless, he cautioned, “It may be a canary in a coal mine, an early indicator to address.”

City planners, meanwhile, are looking at other ways to address pedestrian fatalities. Detroit has seen its tally drop since launching a city-wide effort to fix chronically malfunctioning street lights. And New York is not only increasing traffic enforcement in areas with high numbers of pedestrian crashes but it’s also working to improve the design of problem intersections.