"I didn't know what he was talking about," said the Cupertino resident, for whom a bike is the main form of transportation. Ng was cycling along Mary Avenue with a friend behind her when she approached an intersection. "The only thing that's illegal is entry on red, and I had just entered the intersection when it turned yellow," Ng said. "I was going 12 miles an hour, so I was going slower than the cars were, and I couldn't get across the intersection before the light turned. But I could not have stopped."

That didn't make a difference to the driver of the pickup truck who wanted to turn right onto Mary as Ng entered his path. "He pulled up alongside me, and drove at my same speed as he cursed at me. He was just furious," she said. "He said that he was a bicyclist and he knew not to run red lights."

It's true that bicyclists are subject to the same rules of the road as motorists, but they are also allowed many of the same privileges. This is something many area cyclists are concerned about, especially after the recent assault on a South Bay cyclist. Campbell resident Bo Hebenstreit was beaten by two men on the evening of Sept. 27 as Hebenstreit was riding on Campbell Avenue. Prior to the assault, the men had yelled at Hebenstreit from a passing car and opened a passenger door into his path while stopped at a red light.

The shooting of two motorists in East Palo Alto on Nov. 26 by two bicyclists has also highlighted what some are calling growing tension between the two groups.

But for one area in the South Bay, bicyclists seem to have found a haven. Those from Cupertino and Sunnyvale say the incidents are rare, however, problems still exist between the groups who share the road.

"Too many motorists think that bikes shouldn't be allowed on streets," said Thom Mayer, chairman of the Bicycle and Pedestrian Advisory Committee for the city of Sunnyvale. "I met a woman once who said that she was always nice to bicyclists even when they are where they shouldn't be. But the motor vehicle code lays out a safe way to bicycle on every street."

That includes following all rules and regulations drivers must abide by, such as stopping for stop signs and at traffic lights, signaling when turning and obeying the speed limit. But even experienced bicyclists say they see their peers violating rules on occasion. "I've seen packs of Lycra run stop signs," said Ng, cringing. That combined with motorist frustration and popular images of bicyclists--such as those who participate in San Francisco's traffic-jamming Critical Mass--can lead to situations that are discourteous on one end of the scale and volatile at the other.

"One of the puzzles I've run into is that you can have motorists going down a street, and someone pushes a button to walk across the street. That brings everyone to a halt for a minute, and it's fine," Mayer said. "But a bicyclist may be sharing the lane on a narrow road, and it slows people down for a bit," but that situation can cause angry reactions.

"If you're a bicyclist, you get marked," Mayer adds.

Matt McNamara, a cycling coach who lives off of Homestead Road in Sunnyvale, often leads groups down Foothill Boulevard toward the Stevens Creek Reservoir. "You have to think of cars as your adversary, but you don't want to antagonize anyone," he said. "I haven't been hit by a car in 10 years. I've been scared a few times, but you develop a sixth sense after a while. It's good to make eye contact, and sometimes I'll physically point at a person to make sure they see me."

One of the instances where McNamara uses that technique is when turning left. Cyclists are allowed to turn left from left-turn lanes, and while many roads have bike lanes, the law still permits bicycles to ride in a lane with cars if they are traveling at the same speed. Many cyclists do this to avoid hazards on the right side of the road, where most bike lanes are located.

"Many problems occur at intersections, and every driveway is an intersection," Mayer said. Drivers bounding out of driveways, or pulling out of spots with low visibility, can put cyclists and pedestrians in danger.

Another hazard is drivers who parallel park and open their doors into passing cyclists. "These motorists will pass the bicyclist on their way to park without realizing how fast the bicyclist is going," Mayer said. Several years ago, he was pedaling home from work down Sunnyvale Avenue near downtown, which didn't have bike lanes at the time, so Mayer was riding in the right hand lane.

"I ride a bike with a rearview mirror, and this woman hung on my bumper," Mayer said. "She went around me and kept quite close, and then told me that I was supposed to be on the sidewalk. She was doing that to force me off the road."

But that's a far cry from another incident Mayer remembers occurring about a year ago, where a garbage truck made a right hand turn into a bicyclist, killing him. "If it's you against the car, it's no contest," said Joe Walton, chair of Cupertino's Bicycle and Pedestrian Commission.

Both Walton and Mayer work with their respective cities on making sure the interests of cyclists are represented in local decisions. The Cupertino commission was founded in 1991 when Ng became concerned about barriers that had been placed around the library, leaving no room for cyclists. She approached city council and requested formation of the commission. Since then, the climate for cyclists in Cupertino has improved.

"Cupertino is unique--you can get nearly anywhere without going on arterial streets," said Don Burnett, ride coordinator with Western Wheelers Bicycle Club. "It takes as much skill to ride a bike as it does to drive a car, and around here, you can ride bikes through streets where cars aren't allowed."

The commission is focused on a number of projects, including a footbridge to be erected over Interstate 280 that will link Mary Avenue in Cupertino with Homestead Road. Currently, there is a large distance between the crossings at Stelling Avenue and Foothill Boulevard, and studies have shown that hundreds of students at De Anza College are likely to use the path to travel to class.

Both the cities of Cupertino and Sunnyvale are sponsoring the project with the help of federal funds from the Transportation Equity Act for the 21st Century, passed in 1998. In providing funds to bicycle-friendly projects, "that was a significant turning point, Walton said.

Mayer has similarly worked with the city of Sunnyvale to improve conditions there. Since his incident on Sunnyvale Avenue, bike lines have been striped onto that street and many others. "The city got built out long before bicycles were considered in planning. Many arterials and connectors don't have bike lanes," he said. "For years, the city gave [that concern] as little as possible, but they're now doing as much or more for cyclists than many of the other cities around here."

Sunnyvale's current efforts are revolving around fixing bottlenecks, according to Mayer.

While each city's efforts help cyclists' mobility around town, many of the problems between cyclists and motorists can only be alleviated through reworking public perception. The Cupertino commission will be working with local schools to help increase the numbers of children who walk or ride bikes to school. "The percentage used to be 66 percent, but it's dropped to 10 to 15 percent," said David Greenstein, vice chair of the commission. "Our elementary schools were created to be neighborhood schools, and the more kids that walk or bike, the safer they are."

Walton adds that Cupertino will soon be adopting a public relations campaign known as Street Smarts, which the city of San Jose began in 2002. The program produces bumper stickers and stages events to remind all that populate the roads that we need to share.

"Just as recycling programs have led to a shift in the public behavior and even legislation, we hope Street Smarts will become the rule in San José," said a brochure available at the Street Smarts website, www.getstreetsmarts.com. "As the program develops and grows, and the concept of Street Smarts becomes accepted, we will see a shift in attitude until ultimately, non-compliant traffic behavior, whether driving, walking or cycling, will gain disfavor and a new spirit of cooperation will become the norm."

Some of the attitude shift may have to come from those charged to guard the streets. Law enforcement in general has a reputation among cyclists as favoring those in automobiles. "They're responsive, but a little biased," Walton said, recalling an incident where a young Cupertino man flew over the hood of a car driven by a woman hurriedly driving to work. The responding officer chided the cyclist for not wearing bright enough clothing, even though the incident took place in broad daylight.

But the cooperative spirit that cyclists say needs to improve is already visible in local communities. Greenstein compliments police officers for issuing tickets to young bicycle riders who don't wear their helmets, and Mayer was pleasantly surprised by a Sunnyvale public safety officer who apologized for tailgating.

Bad behavior by one police officer, one motorist or one cyclist can color the impressions of their respective groups. But, as Mayer said, how a city treats those groups can definitely affect the reputation of that area.

"Bicyclists and pedestrians are the indicator species of a livable community," he said.

The Campbell police are offering a reward for any information leading to the arrest of the two men who assaulted Bo Hebenstreit. Contact Campbell police detective Joe Cefalu at 408.866.2179.

Moryt Milo contributed to this article.