San Francisco city officials have been placing flyers on large vehicles, warning the drivers of an impending parking ban.

The new law would ban parking on designated streets from midnight to 6 a.m.

Enforcement starts April 1, when signs go up. Then, starting May 1 violators will be fined.

Dogpatch homeowner Bruce Huie says people living in their vehicles are causing problems.

"If you're defecating out on the street, it's a health issue," he said. "Who's going to pick it up?"

Karl Start tells KTVU he lives out of his van and says the vehicle is his lifeline.

"I'm barely surviving the weather as it is," he said.

City leaders say they're offering to store the large vehicles in exchange for an agreement to go into temporary housing.

Opponents say the ban targets the down and out.

"We're talking about people who are holding onto jobs and able to do so while they're living in their vehicles," said Jennifer Friedenbach of the Coalition on Homeless.

But city leaders say the parking ban is also aimed at those who use city streets to store their vehicles.

Supervisor Malia Cohen, whose district includes the Dogpatch and the Bayview, says she regularly receives complaints.

"The legislation is really simple," she said. "It's an opportunity to say no more."

The Municipal Transit Authority, which oversees parking enforcement, will be holding public meetings in March to educate the public on the ban.