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With his typical modesty, Greg Mahle calls himself "just a regular guy." But the big-hearted Ohio native, like the company he has built, is anything but ordinary.

Mahle heads up Rescue Road Trips, a nonprofit he founded in 2005 dedicated to transporting dogs from pet shelters located in the southern U.S. to adoptive families spread across the northeast.

What Greg has built is more like a movement than a mere shuttle service. Primarily through social media, Mahle's operation has rallied the support of dozens of ardent volunteers, who come out — no matter the weather — to stop-offs along his 4,200-mile route to help walk the dogs onboard the Rescue Road Trips truck. "They believe in what I'm doing," he says of the dog-loving volunteers.

Mahle unexpectedly stepped into the role of doggie driver 14 years ago, but he's truly given himself to the cause of helping at-risk dogs, and to a life on the road. While the dogs may be traveling with Mahle for just a few days to reach their destinations, each pick-up and drop-off loop takes him away from home for one full week — and he makes about 28 trips a year.

Each round-trip journey requires about 660 gallons of gas and six stops at gas stations to refuel the truck and to stock up on any needed supplies. The rig he uses today — the latest in a series of progressively larger vehicles — can accommodate as many as 100 pups per trip. Mahle estimates that he has helped deliver over 50,000 dogs to their new homes.

Despite the impressive numbers, Mahle sees his impact with the same signature humility. "In some small way, I'm making the world just a little bit of a better place," he says. "I'm not changing anything, I'm really not. But if we all got together and we all tried to do one little baby thing today…the world would be a much better place to live in."

Check out the video above for more of Mahle's story.