Everyone they pass seems to know Halferty.

"Because I'm so recognizable in my chair," said Halferty.

If the thermometer's above 60, you're almost guaranteed to see him out. He said he loves the city's trails.

"Once the leaves come on, this is a beautiful area," said Halferty.

Cerebral Palsy put braces on his legs and keeps him in a wheelchair most days.

"I wish I could run for long distances. Bike for long distances," said Halferty.

Along for the ride are grabbers and pokers he used to help keep the trails clean. It started 9 summers ago when Halferty noticed a wrapper on the trail that didn't belong there and cigarette butts.

Grabbing the trash led him off the path.

"I'm going to risk a little off-roading here and just see," said Halferty. "I've fallen into a spring northwest of Douglas."

"He'll call me up. Hey, do you got time to come pull me out. And I do," said Sgt. Gary Lang of the Urbandale Police Department.

Police got to know Halferty the first time their phone rang and they were dispatched out to a trail.

"I was mistaken for a dead, 80-year-old lady," said Halferty who had run off the trail. From behind, they couldn't see his beard.

"I just had bleached my hair blonde that summer. Which I'll never do again," said Halferty.

Lang woke him up, and then noticed all the trash he had picked up.

"It's amazing all the stuff that gets in here," said Halferty, picking up more trash.

"He can spot trash that most people never see," said Lang.

"This is my greatest joy to be outside," said Halferty. "I think of it as kind of physical gratitude and reciprocity for all the good life I have here and I can try to give back in a little bit."

The folks at Urbandale Parks and Rec said Halferty's dedication to their trails has saved the city a lot of money. So if you see him rolling down the trails, tell him "Hi" - or even better pick up a piece of trash so he doesn't have to.