Steven “Highway” Green doesn’t know much about Proposition Q on San Francisco’s Nov. 8 ballot. He has no intention of voting, and all he’s heard is that the measure is aimed at kicking homeless tent encampments like his off the street in exchange for housing or shelter.

That exchange sounds great to Green, if it’s done right. Which could be a stretch.

“I want nothing more than to move off this damn street, get rid of this damn tent and get my life together with a real home,” Green, 54, said the other day on Shotwell Street in the Mission District, as customers of a nearby grocery store strolled by and tried to avoid eye contact. “Look, a couple of people got shot over the weekend right near me. I want to do better with my rehab. It’s hell out here.

“They want to clear us out and give us a place to stay? Hell yeah. I want that.”

But, as with many details carrying devils, this proposition has one crucial provision that opponents — and even the measure’s author, Supervisor Mark Farrell — say will be tough to carry through. That’s the housing or shelter part.

Although Prop. Q does indeed mandate that anyone cleared off the street be offered a shelter bed or housing, that’s virtually impossible to supply quickly, citywide. And quick is what the measure intends, requiring only a 24-hour notice before a camp is swept out.

For people like Green, that’s the sticky part. He said he wouldn’t mind a 24-hour notice if he had a real roof waiting. But if all he gets is a one-night shelter bed, he’d rather just pick up and move a few blocks — which would give relief to one neighborhood but create a new tent scene for another.

“Make that offer of housing real, and we’d all be happy,” he said.

There’s little chance that San Francisco will soon be able to supply long-term places to live for everyone in the 75 or so tent camps dotting the city.

There are usually about 800 people on the waiting list for the city’s 1,300 shelter beds. About 3,500 people were listed as “unsheltered” in the most recent tally of San Francisco’s 6,700-person homeless population, an estimate based on a one-night count in January 2015.

The city’s stock of 6,000-plus units of supportive housing — living space where homeless people are offered such things as substance-abuse services and job counseling — is more per capita than in any other city in the nation. But there are only 300 to 600 new units planned for the coming year.

Farrell said he doesn’t see the numbers as being as daunting as the problem he’s trying to ease with his proposition.

Police already have the authority to clear out camps, but there’s no 24-hour mandate. They generally try to coordinate sweeps with street counselors.

Farrell contends that a voter-approved requirement would bring more structure to the tent-camp problem — something that’s needed, he says, given an ever-more-visible homeless population and residents’ rising unhappiness about it. Last month, he issued figures from a Police Department analysis showing there had been 13 reported rapes in tent camps since January 2015.

“Tent encampments on the street are inherently dangerous and unhealthy places for people to live in, and we have to be creative in San Francisco about addressing that,” Farrell said. “The bottom line is that nobody is getting better living in a tent, let alone standing up on their own two feet and getting their lives together.”

Farrell says he has faith that housing and shelter capacity will improve through a combination of $50 million in new homeless funding and affordable-housing increases on the ballot, and $48 million in new city money committed to addressing homelessness during the coming year. With a third Navigation Center scheduled to open next year in the Dogpatch neighborhood, he said, San Francisco will have the potential of helping more than 1,500 people off the streets each year.

Farrell’s proposition was put on the ballot by a moderate majority of the board this summer after a legislative tussle with progressive Supervisors Aaron Peskin and Jane Kim, who were floating more lenient proposals for clearing camps. Peskin withdrew his, saying the board should defer to the new Department of Homelessness and Supportive Housing.

The agency’s director, Jeff Kositsky, has taken no official stance on Prop. Q. He says he has his own plans and would prefer it if camp-clearance policy were not “politicized.”

One of Kositsky’s first actions upon assuming his post this summer was to create a special tent clearance team. It is now methodically clearing encampments in the Mission District.

Kim, meanwhile, said her proposed tent ordinance is on hold until after the election, because it would be superseded by Farrell’s proposition if it passes. Her plan would give homeless campers at least five days’ notice before being evicted, and require that they be given services and shelter for at least 90 days.

“If you’ve ever spent time in an encampment, you’ll know that 24 hours is not enough time to prepare people to leave,” Kim said. “You need to build trust and take time to connect people to housing and services. And Supervisor Farrell’s plan gives no number of days required for shelter.”

The San Francisco Coalition on Homelessness says Prop. Q is cruel. The city should instead be supplying portable toilets and other services to tent sprawls to make life more livable until campers can be helped into permanent housing, the activist group says.

“The proposition was not well thought out,” Scott Nelson, who is on the coalition’s Housing Not Q Committee, said as he visited a camp of wooden shanties and tents on Seventh Street. “There aren’t enough shelter beds or housing units for everyone, so really, where are people going to go?

“And when they talk about criminal behavior in tent camps, like the rapes, it’s not the homeless who are the problem — it’s the homeless who are the victims,” Nelson said. “We need more help, not more laws just telling us to get off the streets.”

Carl Petersen, an architect who lives and works near Steven Green’s Mission District camp, said he sympathizes with those living in tents, but calls the current situation intolerable. Just the other day, he said, a homeless man with a swastika tattoo beat up another camper near his office, and a week before that a camper died on the street near Petersen’s house.

“I understand how difficult living on the street is, and I’m not saying everyone’s no good on the street, but it is a mess,” Petersen said. “Proposition Q is great, giving someone an option that’s not just moving them along.”

Farrell said he has “great faith” in Kositsky and his staff, and is only trying to support their goals and be compassionate. And he said mandating that camps be left alone for at least five days, as Kim proposes, would lock in a hands-off policy of letting homeless people stay on the street, moving periodically to beat deadlines.

“The fundamental purpose of Proposition Q is that housing in any shape or form is better than sleeping on the street,” Farrell said. “Standing idly by is tantamount to sticking our heads in the sand.”

Kevin Fagan is a San Francisco Chronicle staff writer. Email: kfagan@sfchronicle.com Twitter: @KevinChron

What Proposition Q does

Requires 24-hour notice be given to homeless tent campers before city workers can clear away their tents.

Shelter, housing or a ticket out of town to be reunited with family or friends must be offered to campers being cleared.

Personal property seized during the clearance must be stored by the city for at least 90 days.

Volunteer guide

The Chronicle and other media partners of the SF Homeless Project are compiling a guide on how residents can volunteer or donate items to help people experiencing homelessness.

If your nonprofit organization would like to be included in this guide, we want to hear from you. Please email KShaw-Krivosh@sfchronicle.com with the name of your organization, contact information and the type of volunteers or items you accept.