TULSA, Oklahoma - There's a ballot petition underway for medical marijuana and organizers of it complain they're being harassed by police.

The petition drive gets a lot of attention from drivers, with flags out and a man marching around with a pot on his head.

"A lot of honks, every day it's very inspiring," Oklahomans for Health's Michael Jackson said.

They're pulling in people to sign a petition for a vote on medical marijuana.

They're also registering new voters.

"Been a very successful registration drive as well."

Chris Rogers stopped by to sign up.

Though he doesn't have a doctor's opinion, he believes a nerve issue in his arm could be helped by marijuana.

"And I've been studying it and it could definitely help me with my nerve problems," Chris Rogers, a medical marijuana supporter said.

Police officers have ordered them off what TPD says is private property and out of privately organized, public events like the Friday groceries giveaway downtown.

The petition organizers call that harassment.

Petition organizer Chip Paul wanted the Tulsa City Council to make police stop interfering, but councilors told them to take that up with internal affairs.

"We've tried to go about this in a very respectful way," Paul said. "We understand we're trying to petition for something illegal, we get that, we're out there with a marijuana flag, there's going to be calls."

Paul said after several encounters with police last week, they haven't had any more problems.

Some supporters of the drive are hoping a vote on medical marijuana is the first step to full legalization.

"If they can use for medical use to help someone, that's cool," supporter John Hagger said. "I'm more interested in the recreational use but that's several years down the road; this is the seed being planted."

The drive will continue for another six weeks, and organizers said they easily will have enough signatures to get it on the ballot, and they're signing up voters willing to vote for it.