For east-side commuters, the newly opened bridge linking Kolb and Sabino Canyon roads means a quicker drive home.

It’s much more to Ray Villalobos, Bill Davidson and Fred Gateman.

The Tucson retirees — all metal-detecting hobbyists and military veterans — spearheaded efforts to name the overpass Airmen Memorial Bridge. For them, the new thoroughfare is a way to honor the 18 men who lost their lives in a 72-year-old midair crash, a piece of Tucson’s history they feared would be lost. And it all came about because of a summer hunt that turned up an old .50-caliber cartridge buried in the dirt.

In July, the three members of local club Detectors Unlimited, Inc., struck out in the late morning to scour a vacant lot at Tanque Verde and Tanque Verde Loop roads, across from Emily Gray Junior High School.

“It looked too good to leave it alone,” Villalobos recalled of the spot beneath two salt cedar trees.

They ran their metal detectors over the dirt, and Davidson’s Bounty Hunter sounded a high-pitched beep, the kind of noise that typically signals a penny. Davidson dragged a small pick axe through the soil.

What he found was most definitely not a coin.

Villalobos, a weapons tech during his stint in the Air Force, recognized the crusty piece of metal found just four inches from the ground’s surface: It was an intact .50-caliber round.

They huddled together, wondering where it could have come from. Villalobos remembered a story that his neighbor, also a member of the metal-detecting club, and his buddy had told years ago about a horrific crash involving two bombers from what was then known as Davis-Monthan Army Air Field.

“I started thinking about it,” Villlalobos, 69, said. “Could this be?”

The neighbor, who’s since moved, talked about being 14 years old at the time, sleeping outside in a tent when two early morning explosions jolted him awake.

The club members also had heard stories about kids collecting spent rounds to sell for scrap metal long after the plane wreckage had been cleared.

While the actual digging to discover long-buried treasures is fun, it’s the metaphorical digging — the research — that really makes the hobby come to life.

“It’s what ties things together into a story,” Villalobos said.

About a week after the find, the friends set out to substantiate the old timers’ tales, hitting the downtown library to scroll through newspapers on microfiche machines. Sure enough, two articles confirmed that at 7:40 a.m. on Nov. 30, 1944, two B-24 Liberator bombers crashed into each other about 1,000 feet in the air above the Pantano Wash, between East Broadway and East Speedway. They also tracked down a copy of the military’s accident report, which indicated the crash was caused when one pilot was blinded flying into the sun.

When Villalobos scratched at the bottom of the cartridge, he uncovered a manufacture date of 1943.

“That went from possible to probable,” he said.

They figure it’s not unlikely that some youngster could have pocketed the unexploded ammo as a souvenir, carting it miles away until a concerned mom tossed it out of the house.

Because all three served in the military — Davidson, 64, was in the Air Force like Villalobos and Gateman, 74, served in the Marine Corps — they appreciate how dangerous training can be.

“You don’t put on a uniform and all of a sudden know how to drive a huge bomber,” Villalobos said. “Accidents happen, lives are lost. They should get some recognition.”

They’ve pegged the actual crash site as a landfill, not such a great memorial. But the men thought perhaps the new bridge across Pantano Wash might be a more fitting tribute. Villalobos remembers calling politicians’ offices, looking to see what could be done on the very ride home from the library.

“At every turn, I thought it was going to be dropped,” Villalobos said. “I am amazed. I really am. Sometimes governmental things do get done.”

It was Councilman Paul Cunningham’s office that helped in their quest to name the bridge for the fallen airmen.

“They did such an amazing civic duty coming to us,” Cunningham said. “We were happy to be a part of it. … We’re just lucky to have guys like this veteran trio who are involved in Tucson and Tucson history.”

In an interesting twist, the niece of an airman, a gunner on one of the planes who died in the 1944 collision, stumbled across a news story about the bridge while in Phoenix recently for the Fiesta Bowl. A South Carolina resident, the woman was able to track down Villalobos.

“That was pretty touching,” he said, adding that he, Davidson and Gateman ended up escorting her on Dec. 30 to the crash site where she was able to scoop up some dirt to take home with her.

An orange Nike shoebox holds all of Villalobos’ metal-detecting finds from 2016, which include an old doorbell casing, a woman’s compact from the turn of the century and a lot of pull tabs from cans.

“This is what we mostly find,” he said, smiling as he jiggled the plastic baggie of tabs in his hands.

His 12-year-old grandson in New Mexico — who’s following in Villalobos’ footsteps, directly behind a metal detector — complained that he was tired of always finding those darn pop tops.

“I just told him, ‘Don’t get discouraged,’” Villalobos said. “‘Just keep going. You never know what it might lead to.’”

Contact Kristen Cook at kcook@tucson.com or 573-4194. On Twitter: @Kcookski