In the age of party buses, party barges and pedal taverns in downtown Nashville, one party vehicle is attracting the most attention from Metro government these days.

It's a green John Deere tractor that looks like it belongs on a farm. Instead, it circles the streets of Lower Broadway and the Gulch pulling up to 20 passengers, often bachelorette parties, in a large wagon.

Riders pay $35 apiece to drink beer from the back. It's BYOB, but a bartender is available to make cocktails. Patrons pick their own music playlists, and the rest of downtown has no trouble hearing when they're coming.

Although some Nashvillians scoff at the sight and call it tacky, Off the Wagon Tours has been a hit since Curtis Carney, a 32-year-old part-time police officer in Sumner County, launched his business in April 2016.

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But behind the scenes, Metro is fighting the company on multiple fronts.

In the courtroom, the city has a pending lawsuit against Off the Wagon, arguing that under state law tractors aren't allowed to operate on streets for non-agricultural activities.

More recently, the Metro Council passed an ordinance on July 6 that seeks to outlaw tractors as passenger vehicles in Nashville.

"We're just trying to do the right way to stay in business," said Carney, whose company has expanded to three vehicles. "They have specifically come after our company.

"We've been fighting it from day one."

Carney has kept driving his tractors, though. And he recently scored what could be a key victory to allow his party tractor operation to carry on despite the city's efforts.

It came earlier this month when the Tennessee Department of Revenue agreed to register Off the Wagon's tractors as commercial vehicles. His tractors now have license plates.

Legal fight continues, but state's decision could have impact

The Davidson County Clerk's Office had previously refused to register his tractors.

"As we would say, it was not street legal," Davidson County Clerk Brenda Wynn said of her office's decision last year. "It's a tractor. It's farm equipment. And we don't typically register farm equipment."

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Because Off the Wagon had not been registered, Carney's tractor has been unable to become regulated as a passenger vehicle with the Metro Transportation Licensing Commission.

Metro's dispute with Off the Wagon began on Sept. 9 when Metro police gave Carney a citation for driving an unregistered vehicle. Police issued another citation on Sept. 24.

But Davidson County General Sessions judge dismissed the civil citation last year. But Metro attorneys in January appealed in Davidson County Circuit Court and on May 15 filed an amended appeal, arguing it's unlawful for the company to drive a John Deere tractor and trailer that isn't registered.

Although the case is pending, the state's decision to now register Off the Wagon could undermine the city's argument.

Metro is seeking an injunction from the judge that would prohibit Carney from operating a tractor and trailer that does not have proper licensing, registration and driver's licenses on the streets of Nashville. But Off the Wagon has now seemingly satisfied those requirements.

The Metro Department of Law declined to comment on the case because of the pending litigation.

A spokeswoman for the Tennessee Department of Revenue declined to comment on the department's decision to register the tractors, also citing the litigation.

Veteran Nashville attorney Gary Blackburn, who is representing Carney, said he believes his client's vehicle registration changes the the case.

"They ought to be gracious enough to simply dismiss it now that he's complied in their view," Blackburn said.

"Here's this guy, this entrepreneur, comes up with this idea and people love it," he said. "It's safe, and nobody's been hurt except for some feelings of some people at the police department and Metro Legal. I guess it's just going to be one of these tests of wills and we're just going to have to see what happens."

Ordinance took aim at Off The Wagon, requires 'platform vehicles' to get licensed

The council ordinance, approved unanimously earlier this month, will force so-called "platform vehicles" to get permitted by the Metro Transportation Licensing Commission in order to operate.

The commission already regulates, taxis, limousines and the plethora of new vehicles dotting downtown such as pedal taverns, pedicabs, golf carts carrying passengers and other slow-moving vehicles.

Other platform vehicles in Nashville include Nashville Party Barge, an oversized truck where customers stand and drink from the back.

The ordinance, which goes into effect in October, went further by prohibiting any vehicle that is not listed as a registered vehicle in Metro Codes from being able to operate as a vehicle for hire in Nashville.

With this prohibition, the council's Public Works Committee chairman Jeremy Elrod, the bill's lead sponsor, made clear at the July 6 council meeting that the goal was to target Off the Wagon.

"I've been opposed to something like that operating on the streets of Nashville," Elrod said. "I grew up in Cheatham County, and those kind of things aren't supposed to be operating downtown. They're supposed to be operating on farms or only operating on streets and roads as they travel to farms or to and from the gas station."

But because the state has now registered Off The Wagon, the council's attorney Mike Jameson told The Tennessean that tractors would now qualify under other vehicles under Metro's code.

Hence, the prohibition wouldn't apply to Off the Wagon.

Blackburn, who called the ordinance a "back-door" attack on his client made in retaliation from the legal dispute, said he is reviewing the impact the registration has on the legislation.

Owner says his downtown tractor rides are safe

The bill was framed as a public safety measure, arguing platform vehicles allow passengers to "stand, walk, consume alcohol, and dance on open-air elevated platforms while the unregulated vehicles are in motion and without adequate safety equipment to safeguard passengers from injury in the event of an abrupt turn, stop, or accident."

Metro Transportation Licensing Director Billy Fields said Off the Wagon would be eligible to apply for regulatory permits now that they are registered with the state, so long as they are following local laws as well.

"When the time comes and we start considering those applications, we will consider them like we would any other vehicle," he said.

He said the commission would explore possible safety measures if it does agree to regulate them, noting that his department has never before licensed an open-top motorized vehicle.

The public works department is also in the process of conducting a study on the impact of slow-moving vehicles downtown.

Although patrons who ride Off the Wagon are free of seat belts, Carney and his attorney say the operation is safe and claim there have been no incidents in 15 months.

Carney also disputes any suggestion that his tractors are an impediment to downtown traffic, arguing that, at 12 miles per hour, they move significantly faster than pedal vehicles.

He said his company has been successful because his wagons can hold more people than the typical party vehicle and can accommodate disabled individuals. He also said a tractor is appealing to visitors because it matches Nashville's brand.

"Nashville's a country town and we have a tractor," he said.

What's he say to people who think a tractor doesn't belong in the downtown of a big city?

"Honestly, I can say I haven't had anybody say that," he said. "All of our customers love it."

Reach Joey Garrison at 615-259-8236, jgarrison@tennessean.com and on Twitter @joeygarrison.