MUSA QALA, Afghanistan — Spc. Rene Reyes recalls flying through the air, hoping he wouldn't break anything when he landed. Staff Sgt. Dennis Kirk remembers nothing — the anti-tank mine that exploded under their Humvee knocked him out cold.

They are among an increasing number of U.S. soldiers surviving roadside bombings in Afghanistan thanks to thick armor plate and bulletproof glass windows that now encase Humvees. The front of their vehicle was shorn off, but the armored shell around them remained intact.

Kirk, 24, from Hopatcong, N.J., suffered a concussion and a hairline fracture in his right leg. Reyes, a 22-year-old from Oak Park, Ill., acting as gunner atop the Humvee, had only a cut on his wrist after being thrown nearly 100 feet. Three other soldiers also survived.

After the U.S.-led invasion of Afghanistan in late 2001, the military drew criticism for sending out troops in "soft-skin" Humvees that couldn't stand up to explosives, and the Defense Department struggled to upgrade its fleet.

Today, soldiers say the improved military vehicles are saving lives.

"We'd be dead right now if it wasn't for the armor," said Staff Sgt. Justin Larson, 24, of Othello, Wash., who helped splint Kirk's leg after the blast in late March hit their Humvee from the 2nd Battalion, 87th Infantry Regiment, 10th Mountain Division.

A military investigation team that surveyed the scene in eastern Paktika province said the Humvee was blown six feet into the air, said Cpl. Jose Cruz, a 22-year-old from Brooklyn who was riding in the back seat.

"We trust our lives with them," Cruz said. "They're damn good vehicles."

Militants have been using roadside bombs more than ever this year in Afghanistan, mimicking the tactics used by insurgents in Iraq. The military says it finds or detects about 60 percent of the bombs before they go off.

A roadside bomb in Nangarhar province this month killed two U.S. soldiers conducting a security patrol. Last month, a suicide attacker detonated his car bomb near a U.S. coalition convoy outside the U.S. base in Bagram, wounding two Afghan boys and damaging a coalition vehicle.

Lt. Col. Chris Toner, commander of a new American base outside Musa Qala in southern Helmand province, doesn't let his soldiers leave camp unless they are in a factory-made armored Humvee, shunning even the add-on armor that strengthens older vehicles.

"I have to look at the moms, dads, wives and kids (of soldiers) and tell them I'm doing everything I can to save lives," he said. " ... As commanders we have to do everything we can to mitigate the risk."

Toner said that during his last tour here, which ended in April 2004, he didn't have all the armored Humvees needed. A roadside bomb killed one of his soldiers in a soft-skin vehicle.

But when he arrived for a second tour in February, his needs were met. Four roadside bombs have hit his Humvees since then, and none of his soldiers have been seriously injured or killed.

"I'm absolutely convinced that the way the Hummers are built today have contributed to saving the lives of my soldiers," Toner said. "The United States military and the Department of Defense have responded to the need."

In late April, Lt. Sean O'Brien was traveling in the front seat of a Humvee in southern Zabul province when he heard a bang and thought the vehicle hit a rock.

"Then all of a sudden, there was a huge explosion and everything went black," said O'Brien, an officer in the 5th Battalion, 25th Field Artillery Regiment, 10th Mountain Division.

As the Humvee drove into a dry riverbed, it hit an anti-tank mine triggered by the pressure of the tires. One of those tires was thrown 300 feet, said O'Brien, of Sanborn, Iowa.

But the four occupants suffered only minor injuries.

Pfc. Harvey Paige, of Texarkana, Texas, who was riding in the gun turret of the Humvee, credits the armor plate under the engine for saving his life. The 28-year-old plans to visit the Humvee plant near his home when he gets back to the states.

"I'm going to go down there and say, 'Hey guys, thanks for that extra armor,' " he said. "That's what saved us."