He got the text in the middle of treating patients. He was needed in the morning — and so was his dark blue 2002 Jeep Wrangler.

Brian Bickerton had a packed schedule at his New Port Richey chiropractic office that day. But he told his assistant to rearrange his schedule.

Instead of pulling into his office parking space on April 6, Bickerton slid into the beige driver's seat of his Jeep and headed for the woods of north Hillsborough County.

There he joined a team of Jeep owners who would spend the day tearing through muddy trails to help search for a teen girl who had been missing for more than a week.

"Usually when the Sheriff's Office is telling people to get out of an area," Bickerton said, "that's when we're coming in."

That's because Bickerton and his fellow Jeep owners can go where few else can. The Volunteer Jeep Search and Rescue Unit of the Pasco County Sheriff's Office's brings off-road enthusiasts together to help first-responders reach otherwise impassable terrain.

The volunteer unit was formed in January to conduct search-and-rescue missions or offer aid in emergencies and disasters. They've worked in the Tampa Bay region but are ready to go across the state if needed.

Their first mission in April was to help recover the remains of a 17-year-old teen who had gone missing in Flatwoods Wilderness Park north of Tampa. Then on May 19 they were sent to the woods in New Port Richey to search for a missing 70-year-old man.

"Jeepers are amazing," said the unit's coordinator, Pasco sheriff's Col. Arthur Madden. "They want to help and they want to get out there."

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The unit was the solution to an age-old Pasco problem: How can deputies maneuver through large swaths of woods, flood-prone areas and other kinds of rough, inaccessible terrain in a wide-open county?

The solution? Jeeps. The iconic 4x4 of World War II that is as popular as ever with off-roading enthusiasts today.

Volunteers have long been used by local law enforcement for a variety of duties: neighborhood watches, helping citizens, taking calls, directing traffic, helping with mounted horse units. However, there wasn't much precedent for getting citizens to volunteer their private vehicles to help a specific law enforcement agency.

That's why Pasco's Jeep unit is so rare. Madden believes it is the only agency-affiliated one in the state, and it is one of the few in the country, joining off-road search-and-rescue units in states such as Arizona, Oregon, Washington and Utah.

Sheriff's officials expected the program would take time to get started. Six months and 30 volunteers later, the program has already exceeded those expectations.

"We thought it would take a year to do that," said Rick Cochran, the director of crime prevention and community engagement at the Pasco County Sheriff's Office.

The unit quickly went from idea to reality, Madden said, because of the passionate nature of the volunteers.

To join, applicants must have the proper insurance, be able to pass a criminal background check, have the time to train — and, of course, a Jeep 4x4. From there everything else is donated, such as gas and supplies. The Sheriff's Office's own Jeep was donated by the Ferman Automotive Group.

The group was also trained in first aid, CPR, and Community Emergency Response Team, or CERT training, which teaches basic disaster response skills to prepare them for situations they may face.

They also tackle obstacle courses together to practice maneuvering in their Jeeps, and to build team camaraderie.

During a recent exercise on June 24, the volunteers tore through muddy ditches, climbed over steep hills and motored single-file through the woods behind Safety Town, a miniature city in Shady Hills used by the Pasco County Sheriff's Office to educate children on safety.

These exercises gave the thrill-seeking volunteers the chance to push the limits of their vehicles.

Lonnie Redmon, a Pinellas County Sheriff's Office sergeant who volunteers with the Pasco team in his spare time, tried to plow his Jeep through a shallow pool at the bottom of a trench. He inched his tires along the mucky bottom until his cab started filling with water. Then he decided to back out of it.

But even if he had trapped himself in there, someone in his unit would have been ready to hook his Jeep to theirs and pull him out. Trying and failing is all part of the Jeep driver's mentality. It's an invaluable part of the unit's team building exercises.

"The saying out here is if you don't get stuck or break something then you weren't playing hard enough," Bickerton said.

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The volunteers come from a variety of backgrounds: Several have spent time in the military or law enforcement; one teaches school bus drivers; another works in a funeral home.

They heard about the group through advertisements and word of mouth, but one thing drew them all together:

"There's nothing better than being able to help somebody," Bickerton said.

Bickerton served in the Air Force reserves in the 1990s and worked on search-and-rescue missions, often responding to plane crashes. He had long desired to return to that kind of work. Then in August 2015 he was diagnosed with stage 4 tonsil cancer. He started thinking of ways he could give back to society.

Then he heard about the Jeep unit. He looked at his Wrangler, which hadn't seen much action outside of a parking lot, as a way he could do that. Six months after treatment, his cancer in remission, he volunteered for Jeep duty. Now he's one of two team leaders.

Jim Campbell, a former Hillsborough County sheriff's deputy and current unit member, said the unit has quickly gained respect. He's seen firsthand the gaps between civilians and law enforcement when they have to work together on assignments like the one in Hudson. But the Jeep unit has been a different story, Campbell said, and he thinks that's because of their mission.

"We weren't there to twiddle our thumbs," he said. "We were out there to physically do something."

Times senior news researcher John Martin contributed to this story. Contact Chris Bowling at cbowling@tampabay.com or at (813) 435-7308. Follow @chrismbowling.