At the intersection of the two country roads, charred debris lies strewn haphazardly. The earth around it is scorched.

It is here, in this corner of Dumas, Texas, that a sport utility vehicle and a gas tanker collided Sunday afternoon. The tanker's flammable cargo sent both vehicles up in flames, seriously injuring the truck driver and killing all five passengers in the Chevrolet SUV.

All of those who died were teenagers.

The crash, coupled with another one in Warren, Ohio, the same day, highlight that motor vehicle wrecks continue to be the No. 1 killer of youths in the United States.

Such accidents took the lives of about a quarter of the 15- to 24-year-olds who died in 2010, according to the most recent numbers from the Centers for Disease Control and Prevention.

They outpaced the other top culprits: firearm wounds, homicides, suicides and accidental poisonings.

But the wrecks mask a broader improvement: Overall traffic fatalities have been dropping in a "historic downward trend," according to the National Highway Traffic Safety Administration. In 2005, it tallied 43,510 traffic deaths; in 2011, there were 32,367, the lowest level since 1949.

In 2009, motor vehicle crashes were the 11th-leading cause of death. That marked the first time since 1981, when data were first available, that motor vehicle crashes were not among the nation's top 10 causes of death.

A fatal mistake

It wasn't clear where the teens were headed in the SUV when, authorities say, the driver, 16-year-old Jacob Paul Stipe, failed to stop at a stop sign.

It was a fateful mistake.

As the SUV entered the intersection, a truck smashed into its passenger side, CNN affiliate KFDA reported, quoting authorities.

Paul died at the scene. So did his four passengers: October Dawn Roys, 17; Elizabeth Kay Roys, 15; Derrek Lee Hager, 17; and Christopher Lee Moore, 17.

The truck driver, Ezequel Melecio Garcia, was flown to a hospital burn unit in Lubbock.

Best of friends

The teens were friends, said Star Tovar, assistant manager at the local Dairy Queen.

"It was always them together, all five of them always together," she told CNN affiliate KVII.

Chris had recently moved to the area.

Elizabeth and October, who went by the nickname Toby, were sisters. October leaves an infant daughter.

Their parents, Robert and Sheryl Roys, wept as they spoke to the affiliate.