San Diego — The name police have given the crashes is "vehicle versus bike." Dave Rierson, who works at Mission Hills Bikes on West Washington Street, has been in three of them in the last six months. And, in each case, he rode the bike. In the first one, he was riding with a friend on Harbor Drive near the airport, when the mirror of a passing cab "clipped my friend and threw him into me. Both of us went down in a ball of metal and human," says Rierson. He was all right, but his friend "lost a lot of skin on the road."

Another car struck Rierson, not long afterward, as it turned right off Washington toward Scripps-Mercy Hospital. Says Rierson, "I flipped over his hood and went into a barrier. That one hurt a lot."

Finally, a month ago, Rierson collided with a car that turned left in front of him as he rode west on Madison Avenue in North Park. "My bike went right, I went left," he says. "The next thing I know, people up above me are going, 'Don't move.' That was the only time I had to get an ambulance. I hurt my wrist and elbow good, and I'm still getting treatment."

Rierson thinks car drivers don't get enough education about laws governing bikes. He also wants more bike lanes on San Diego streets. The police, he claims, assured him that, in the case of each collision in which he was involved, he was not at fault. That may seem unlikely to a motorist such as Kathy Adair, who is angry at the way some bicyclists ride the wrong way on neighborhood streets, fly through four-way stop signs without even slowing, and make other dangerous maneuvers.

A schoolteacher who lives in Bankers Hill, Adair has agonized over bikes in traffic. Once, with her young children along in the car, she almost hit a bicyclist who had run a red light. "I didn't want my children to see me kill somebody on a bike," she says.

Police records show that two bicycle fatalities have occurred in San Diego traffic this year. Last year there were seven, including the death of David Markham, a Marine who was hit from behind by a drunk driver on Miramar Road on Halloween night. Detective Jerri Sober of the San Diego Police Department's Traffic Investigations Unit tracked down the hit-and-run driver. He had swerved off the road, she says, and hit Markham, who had a reflector on the back of his bike.

Despite that case, Jim Bolen, a community relations officer with the traffic division, claims that collisions, "the majority of the time, are caused by the bicyclists themselves." Take the problem of turning left at a busy intersection. If bicyclists are "going to be in the left-turn pocket," says Bolen, "they should be in the outside of that pocket and outside of the traffic, as it's moving, without interfering with it. Most of them are in the middle of the lane interfering with traffic, and with these days of road rage, boy, that's the quickest way I know of to get somebody mad. And they've got to realize, car versus bicycle, they're going to lose.

"No place you're going, nothing you're doing, is worth your life. Bicycling is great. But you've got to remember, yield the right of way. I don't care if you are right, you don't want to be dead right.

"And leave your attitude at home. People make mistakes. The way I cope with driving is I make believe everybody is two years old, and I have to take care of them. If they do something silly, it's a two-year-old making a mistake. I'm going to forgive him. I don't tell him what I think about his mother. Enjoy your ride. You're out there to enjoy the ride.

"Yeah, maybe that driver cut you off, maybe he didn't see you. I rode a motorcycle for eight years, and the way I survived was to make believe I was invisible, that nobody saw me. If you ride a bicycle, same thing, make believe you're invisible. I don't care if you have eye contact; don't trust it, always yield the right of way. So what if you've got to stop. Big deal. You're going to get to where you're going alive."

But Jim Baross, who teaches classes in the American Bicyclists' Effective Cycling Program, takes exception to the idea of riding as though you're invisible. "You should ride to be visible," he says. "Motorists are good at seeing and avoiding things that they expect."

Baross confesses to being a "bicycle activist." In 1976, he led a tour of cyclists across the United States sponsored by Adventure Cycling. Today, besides teaching people about riding bikes, he chairs SANDAG's Bicycle Pedestrian Advisory Committee. He is a member of the Bike Coalition of San Diego, a nonprofit that advises city staff, and sometimes the city council, on where and how to change roads to make them safer for bikes. Every weekday he rides his bike both ways between his home in North Park and his job downtown as a supervising management analyst with the city.

The biggest problem bike riding faces in our communities, according to Baross, is in our minds. "Cities, as well as the general public in America," he says, "need to get over this bicycle-as-toy kind of approach and car-as-the-only-choice. Bicycling and walking are way more efficient for an individual and for the community than using a car, especially on short trips. And people who are relatively able-bodied and can afford $100 to get a bike can save $6000 a year off the cost of operating a car for the same trips.

"A logical approach to transportation choices would mean that more people would take more advantage of more of the alternatives that are better for everybody. Why don't they? They don't think about it. I don't know how many millions of dollars are spent trying to sell you on the sex appeal, romance, and virility of driving a car. And the advertising that you see for bicycling is gonzo, thrill-seeking, recreational stuff, not 'Get to the store and back, you don't start your car.' But it does make sense to choose a different alternative."

People often say that bikes should not even appear on the road. The California Vehicle Code, however, states that bicyclists have an equal status on the roadway to that of motorists. According to Baross, "Because you're in an SUV or a stretch limo or a Mack truck doesn't mean you have any more right to road space than I do. I know that people say you'll get run over. I can get beat up after school by a bully, too. That doesn't make it right. And I get bullied off the road, on occasion, when someone thinks they have a right to the space and I don't. I'm taking up 12 square feet of space, 6 feet by 2. They're taking up 30 square feet, and they call me a road hog. That's not right.

"Bikes belong. And if the guy honks at you, he saw you. That's a good thing. If drivers wave a finger, they saw you. But they're wrong if they think you don't belong there."

Although he has heard of no organization that tries to get bikes removed from traffic, Baross wonders whether road engineers aren't trying to drive them out with some terrible intersection designs. In agreement with many other cyclists in San Diego, he cites Pacific Coast Highway at Barnett as an intersection that is designed only for cars to negotiate. Other difficult places for cyclists are bridges over freeways, such as the Clairemont Mesa Boulevard and Washington Street overpasses on Highway 163.

Both motorists and cyclists, claims Baross, ask too much of bike lanes. "When people say there are no bike lanes, I scoff and yell. Bike lanes don't protect anybody. People get killed all over the place because of motorists' lack of attention or cyclists staying in that bike lane when they should have gotten out of it." A crash occurred a few years ago on southbound Fairmount Avenue near Montezuma Road. The motorist swerved, says Baross, and killed a cyclist riding properly in the bike lane.

Baross does not dispute, however, the contention of the SDPD's Bolen that bicyclists cause most of the collisions with cars. A person must have a license to own a bike but not to ride one, as motorists do to drive a car. So they don't have to take a riding-competency test or obtain any education on how to ride a bike in traffic. And, says Baross, most cyclists think they know all there is to know about riding a bike -- until they take a class like the one he teaches.

Public schools in San Diego stopped offering driver's education long ago. But during P.E., "They teach students how to play dodgeball," says Baross, "which is not a lifetime skill. Bicycling is good for fitness, and it expands the freedom and the opportunity for kids to move around their neighborhoods without relying on Mom to get them somewhere. Now would be a great time to change some of the P.E. curriculum to bicycling and walking. People need to know how to get across the street, too."

Like most cyclists, Baross is enthusiastic about the benefits of riding bikes. "Every day I get two half-hour workouts. I'm going to live longer than I otherwise would, I'm going to be healthier, I'm going to feel better every day, and I can eat more. And I make that workout part of my travel time. The departments of health in California and nationally say we've got a bunch of fat people in the U.S. because they don't build exercise into their lifestyle. They take the elevator instead of walking. They take the car instead of bicycling. So the health benefits for me are great. And then I'm not a load on the community because of my health.

"You don't breathe my exhaust. I'm not using petroleum fuel; I'm not a reason we're going to bomb Iraq. It would be a good idea if we weren't so dependent on Middle Eastern oil. But how do you get less dependent? You ride a bike."

Despite his involvement in three collisions with cars, Rierson is also enthusiastic about bicycle riding, which he calls a great sport. Rierson's boss, Eryn Pecka, who owns Mission Hills Bikes, is more voluble in his praise.

"Bike riding is fun," says Pecka. "Also, it reduces congested traffic and is good for the environment, especially on short trips, like to and from the grocery store. And, as a bike rider, trust me, I can tell you that stop-and-go traffic promotes much smog.

"By riding bicycles, you tend to see more of your surroundings. In cars, people don't see the neat stuff around town, like the artwork that's up and down the sidewalks in Hillcrest. We live in a beautiful city. Also, riding slows down the pace of life a little bit. It helps me find my center."

Pecka, who often rides to Oceanside, Julian, and other places in the county, recently attended a bike race in San Francisco. "After the race," he says, "I was sitting in a restaurant enjoying some lunch, and some guy started complaining about how bad the traffic was because all the streets were blocked off for the race. And I thought to myself that the reason the streets are so crowded is not because of the bike race but because there are so many cars."