SAN FRANCISCO -- James Hudson moves warily through this car-choked city, looking over his shoulder, bracing for the next tense face-off or retaliatory attack.

He is one of 350 often-harried civilian officers who perform what many motorists consider an outright act of war: He hands out parking tickets.

Especially in the congested Financial District, summons writers such as Hudson are often considered urban predators, loathed for lurking sharklike on bicycles or in street buggies, and for such stealth tactics as chalk-marking tires and wielding prewritten tickets.

As a result, officers now deal with the sidewalk version of freeway ferocity: parking-ticket rage.

In 11 years on the job, Hudson has been cursed, had his foot run over, been shot with a pellet gun and had his knee whacked by marauding drivers. Colleagues have been spit on and assaulted, one with a baseball bat.

For Hudson, such violence comes with the job. "Some people don't know how to control their anger," he said.

But officials are fighting back. After a rise in attacks, the city is pushing stronger protection for officers, such as requiring all parking control vehicles to be equipped with Mace and cameras.

A bill being introduced in Sacramento would make it a felony to strike any parking control officer in the state. Currently, penalties range from fines to community service.

"It's a public safety issue," said Assemblyman Mark Leno (D), who is sponsoring the bill. "Nobody takes a traffic ticket with a smile."

Assaults on parking control officers in San Francisco rose from 17 in 2005 to 28 last year. During one week in November, four parking officers were attacked. Two of them were hospitalized.

A male officer was repeatedly punched and his car window was broken. A female officer suffered a concussion and a dislocated shoulder.

A 30-year-old suspect in the latter attack faces three felony counts. A judge raised her bail from $70,000 to $100,000.

Parking problems have sparked violence between motorists as well. In September, a 19-year-old man was stabbed to death in an altercation over a parking spot.

San Francisco has 365,000 registered vehicles and 320,000 on-street parking spots, supplemented by 280,000 spots in public and private garages and in off-street lots. The daily influx of 35,000 commuters can make snagging an on-street parking space in a busy area a frustrating roll of the dice.

Like many of her colleagues, the 28-year-old officer injured in November said she rarely eats in restaurants without wearing a jacket to cover her uniform. After the attack on her, dozens of parking control officers rallied to demand better protection.

"Nine out of 10 people we meet on our jobs are angry," said the officer, who asked not to be identified. "People have quit, the abuse is so bad."

LaWanna Preston, staff director of Local 790 of the Service Employees International Union, which represents Bay Area parking control officers, said that in seven years as a parking officer in Berkeley, she was harassed by doctors, lawyers and college students.

"People see you as an opportunity to sound off about the system," she said. "They're mad about the ticket, but it's also about how the government is always ripping them off."

In San Francisco, the 1.9 million citations issued last year generated $50 million -- the third-highest revenue source behind the airport and port districts, Preston said. Yet parking officers make only $40,000 a year.

"They generate lots of money, but they don't get paid that much," she said. "The money is not going into their pocket."

Hudson, 46, takes the verbal abuse with a Zen-like calm. One recent morning, he chose not to ticket a motorist who had double-parked on a busy street while dashing into a store to buy coffee. Instead, he gave the man a verbal warning.

The motorist drove off, telling Hudson to "get a real job."

Hudson's beat takes him past industrial garages and worn storefronts south of Market Street. Dressed in a blue sweater jacket, pants and a badge, he carries -- along with his Mace -- a hand-held computer and a mini-printer that enable him to write a summons in less than a minute.

On most shifts, he issues 80 or more tickets.

Sometimes he walks. Sometimes he rides a hybrid bike or a city-issued scooter. But one part of his job stays the same: insults from motorists.

In a one-hour span recently, Hudson wrote half a dozen tickets. He also gave a few warnings -- such as one to window washers who parked their truck at a meter whose gauge had been obscured with gray paint.

Later, he called for a car parked in a loading zone to be towed. Then he spied a car already sporting a ticket on its windshield. After a check, Hudson learned that the car had not been moved in the 90 minutes since the first ticket was written. So he issued a second $50 expired-meter summons.

"This is not a punishment," he said. "It's a learning curve."

Nearby, he saw a van parked on the sidewalk. Hudson tried to locate the driver, calling into an apartment building nearby. Then he wrote a $100 citation.

Within moments, plumber Jeremy Baldwin, 36, emerged from the building, walking toward his van with a dazed look.

He admitted that he is a repeat scofflaw, one year collecting $7,000 in tickets. He said he rarely buys a vehicle worth more than $1,000 because so many have been towed for nonpayment of fines.

"Hey," he said, "if I'm an idiot, I'm an idiot."

Baldwin stuffed the ticket into his shirt pocket. The fine, which would be taken out of his check, meant he would not make any money that day.

"It's a total wash, all my hard work," he said with a sigh.

But Baldwin isn't the type to blame the messenger.

"No hard feelings," he called out to Hudson. "You're just doing your job."