The intersection at the foot of the University Bridge—the site of a fatal collision two weeks ago between a dump truck and two cyclists—contains two haunting tributes to the victim who died, Bryce Lewis. The first, a white-painted "ghost bike" like the ones that went up around town a few years ago, perches on top of the road sign marking the intersection, right in front of Romio's Pizza & Pasta; a sign attached to the bike reads, "Bryce Lewis Struck and Killed by a Dump Truck 9/7/2007. He was 19." The second is much more explicit—and eerie. It's a sign painted right in the middle of the bike lane where Lewis was killed; in all capital letters, it reads, "A CYCLIST DIED HERE." But the agitprop that biker activists have put up in Bryce's honor doesn't tell the whole story.

Finding out exactly what happened the afternoon of September 7 is close to impossible. One thing, however, is certain: Lewis was riding a fixed-gear bike, an increasingly popular but notoriously dangerous style of bicycle. Fixed-gear bikes, or "fixies," are extremely difficult to slow down on steep hills—like the one you take from Capitol Hill to Eastlake Avenue and the University Bridge.

Brakeless fixed-gear bikes were never intended for ordinary commuting. Originally, they were developed to race on velodromes—circular tracks where the ability to build up speed is all-important. Over time, they became popular among messengers, messenger wannabes, and ordinary commuters. Although some bike shops still cater mostly to track racers, others sell fixed-gear bikes to commuters—"mostly hipster guys" and a few women, according to Velo Bike Shop owner Lloyd Tamura.

In recent years, fixed-gear bikes have become ubiquitous in hipster-saturated cities such as Seattle, Portland, Austin, and San Francisco—valued as much for their appearance as for their functionality. Tamura says sales of fixies have spiked in the past four years—a statement backed up by employees of other local bike shops. Several shops, including Counterbalance Bicycles on Queen Anne and Mobius Cycle downtown, specialize in fixed-gear bikes.

Eyewitness accounts differ as to the speed of the cyclists and the truck; whether Lewis and Caleb Hall, his riding partner, were riding safely or aggressively; and whether the truck's driver, a man whose name has been redacted from police reports, stopped and looked before turning right from Eastlake Avenue onto Fuhrman Avenue. We do know the driver took a right turn directly into the cyclists' path; that he hit both of them—Lewis first, then Hall—and dragged them under his truck for several feet; and that by the time he stopped, Lewis, who was riding in front of Hall, was dead. The official cause of death was blunt force trauma to the head; according to eyewitness Rich Hinrichsen, Lewis, who ended up behind the truck's right front tire, was lying in "an impossible position," with "blood pouring out of his mouth and the back of his head... smashed." According to all eyewitness accounts, neither cyclist was wearing a helmet.

Those details are about the only ones on which all eyewitnesses agree. From there, the accounts diverge. One witness told KING-5 news that the cyclists were going upward of 30 miles an hour (not a difficult speed to attain at the bottom of the steep hill that leads down to Eastlake Avenue from Capitol Hill) and "shouldn't have been trying to pass a dump truck on the right-hand side on the curb to begin with." Seattle Police Department (SPD) spokesman Mark Jamieson recounts a similar story based on reports from police investigators, noting that eyewitnesses told police the cyclists, particularly Lewis, were "not really following the rules. He [Lewis] was racing, riding very aggressively, weaving in and out of traffic, and just not operating his bike safely."

However, Hinrichsen, who was jogging home from work and says he saw the accident unfold about 100 feet in front of him, estimates the two were turning onto Fuhrman Avenue at about 11 or 12 miles an hour—more slowly than the truck, which he says turned from the left-hand lane (not the curb lane, which was partly obstructed by a construction zone) at about 15 miles an hour. "I did not anticipate this event, and I was not really aware of the position of the truck before the collision. I just recall seeing the truck plow into the cyclists." The truck driver, he adds, did "exceed the speed of the cyclists. I was surprised by how fast the truck could negotiate that turn."

Dan Heidel, a member of Point 83—an online forum where cyclists talk about the politics of cycling in Seattle, trade maintenance and repair tips, and organize rides—points out that eyewitnesses reported that the truck dragged the two cyclists nearly 25 feet. "That seems to indicate the dump truck was moving quite quickly, to not be able to stop after a right turn," Heidel says. Point 83 was largely responsible for the ghost bike and bike-lane sign at the site of the accident.

The crash site, an intersection that sees 30,000 cars a day, is notoriously dangerous for cyclists ("scary as shit," one Point 83 poster called it). Although Seattle Department of Transportation (SDOT) spokesman Gregg Hirakawa says SDOT has no specific records indicating that the intersection of Eastlake and Fuhrman avenues is more dangerous than other trouble spots. (SDOT doesn't keep crash statistics by intersection.) "This is a major connection [for cyclists], and it needs improvement," says David Hiller, advocacy director for the Cascade Bicycle Club.

Five years ago, bike planners at the city identified Eastlake Avenue as "the most heavily used north-south corridor" in Seattle and "strongly recommended" addressing bike safety in the area. But since then, the city has been slow to support innovative ideas that could make bikers safer and more visible, including installing special colored lanes to increase biker visibility, phased pedestrian lights (which turn green before the main signal to give bikers a chance to make it into an intersection), eliminating lanes of traffic ("we only have a certain amount of roadway," Hirakawa says), and bike-only signals.

The city did just install a "green lane" in its Sodo truck facility to see how well the green paint stands up to repeated pounding; if it proves long-lasting, Hirakawa says, the city will install it in places where there are "conflicts between cyclists and vehicles—turns where cars and bikes are using the same piece of real estate."

Bryce Lewis was, by all accounts, a generous, sweet, and conscientious kid. Photos show a beaming, skinny boy just barely past the age of high-school pimples, dressed up as a sailor for Halloween and goofing with a guitar in front of a chalkboard. He had just moved to Seattle from Denver a few weeks ago to join his close friend Hall and attend the University of Washington. It was the first time he had moved away from home. According to his uncle, Jose Duran (who posted some remarks on the Point 83 forum but said it was too soon for him to talk when I contacted him for this story), Lewis was "a very kind, compassionate person" who played in a rock band and loved making films and other kinds of art. A high-school friend from Denver describes Lewis on his blog as "the best drummer I've ever heard, and the best guitarist I've ever played with."

Point 83's Heidel, who met Lewis on bike rides a couple of times, says he found the accident particularly tragic "because [Lewis] just moved here and he moved here out of choice. He thought Seattle was a great place. So there's this kind of sense that we let him down."

Ordinary road and mountain bikes—the kind you still see most people riding—are equipped with what's called a "free wheel" on the back wheel—a kind of ratchet that allows the bike to coast when you're in motion, so that you don't build up as much speed going downhill.

On a fixie, the chain drives a cog that's bolted, or fixed, directly to the rear wheel. As a fixed-gear bike moves forward, the wheel moves forward too, making it impossible to just stop pedaling. If you stop pedaling abruptly, you fall off. To stop, you either use a front hand brake (or two brakes, a front and a back), push backward against the motion of the pedals, or lock the wheel in place (by lifting up your back tire while in motion) and skid. Stopping without a brake from a fast clip thus requires tremendous physical power.

John Yee, a salesman at Gregg's Greenlake Cycle who has ridden a fixed-gear bike for the last few months, likes the "fun, way-different" feel of a fixed-gear bike. "It's challenging. I like learning a new skill." Plus, "if you're good at balancing, you can do track stands [standing up on the bike while pushing back and forth] all day long."

One practical benefit of riding a fixed-gear bike is that it's simple. Maintenance and repairs are minimal because there aren't many moving parts, and aesthetically, they're extremely beautiful to look at. They're also frequently less expensive than geared freewheel bikes, for the same reason: Fewer parts means they're easier to build.

But again, the reason most people who ride fixies say they do so isn't practical or aesthetic, it's experiential: Fixed-gear bikes are incredibly fun to ride. Because they transfer most of the mechanical work of riding to the rider, riding a fixie just feel like a more "pure" experience than riding a bike that does half the work for you. You can't stop pedaling, and stopping (particularly on a bike that doesn't have any brakes at all) becomes a challenge, both mentally and physically. Go up and down a few hills on a single-speed, fixed-gear bike and you'll quickly find yourself in amazing physical condition. Yee says that as long as "you're a pretty good road biker, you shouldn't have any problems once you've been riding it for a couple of months."

I've been riding bikes for about 25 years. I stayed away from fixed-gear bikes for the same reason I was initially nervous about switching to a road bike: I was worried I wouldn't be able to control one. Taking a few different models out for a test ride the other day at Tamura's Velo, I had my fears confirmed. But I also saw exactly why so many riders find these bikes appealing. On the first one I tried, a Giant model with both a front and rear brake, I nearly crashed when I instinctively tried to coast down a hill. The pedals kept moving, my legs seized up, and it took a minute to recover my balance and keep pedaling forward. After trying a few different fixed-gear bikes, I eventually graduated to the Bianchi Pista—a stunningly gorgeous silver bike with one fixed gear, no brakes, and handlebars so low you have to look up to see the street. "You might want to try this one on the sidewalk," Tamura told me. It was by far the scariest bike I've ever ridden—the experience of stopping by pushing back against the pedals is the most counterintuitive thing a longtime free-wheel biker could ever experience—but the power and control was indescribable. I have to admit it—I want one. But I also know that, for riders like me (those who don't have lightning-quick reflexes and quads of steel) they're incredibly dangerous.

The Seattle Municipal Code requires every bike to be "equipped with a brake that will enable the operator to make the braked wheel skid on dry, level, clean pavement"—standard federal language that applies in many cities across the country. Where the issue has gotten murky is the definition of a "brake." SDOT spokesman Hirakawa says all that matters is whether you can stop. In contrast, the Seattle Police Department seems to think some kind of separate brake is required, but SPD spokesman Jamieson says, "It's not a priority for us to go out and cite people if they don't have one."

In cities such as Portland and Milwaukee, however, judges have ruled that a "brake" means a hand brake, not leg power. Like "glass art" bongs and "vases" that are used as crack pipes, however, most cities don't have strictures against selling fixed-gear bikes, although many cities only sell them with brakes (with the implicit assumption that the buyer will take them off). The result has been that some bikers have ended up with tickets, while others have simply attached fake brake levers and cables to their handlebars in hopes of eluding unobservant police.

Mark Ginsberg, an attorney in Portland who has represented messengers and other fixed-gear bike riders who have gotten tickets from the city, says the only issue with fixed-gear bikes exists in the minds of a handful of Portland police. "There has been no problem in Portland concerning fixed-gear bicycles and safety and higher [rates of] crashes," Ginsberg says. "There happen to be two Portland police officers who've taken this up as their personal issue and frankly, they're ticketing the same people over and over." Judges, however, have ruled against Ginsberg's clients almost without exception, saying that fixed-gear bikes do not have a "device for slowing."

Indeed, as Heidel (who rides a regular road bike) points out: "If you lose your foot contact with the pedals, you're screwed." If you're inexperienced, that's doubly true. Which is why bike experts tell you to spend lots of time practicing on dry, flat, even ground before going out into traffic, much less up and down hills. Unfortunately, that's not what many people are doing.

Tamura calls fixies "one of those toys that people want right now. You can't tell them, 'You're not experienced enough to ride this.'" Tamura says most of his customers who buy fixed-gear bikes elect to remove the front brake, or to buy a model, like the Pista, with no brake at all. Although Tamura says he wouldn't "advise one way or another" on whether to install a brake, he adds, "If you're going down a street and a car pulls in front of you, you don't have time to slow down. You're going to fly off the bike. Riding downhill on one of these—if you're not experienced—is suicide."

Lewis's funeral was last Thursday in Denver. Seattle friends and fellow bikers were waiting this week for Hall, who could not be reached by press time, to return so they could hold a memorial ride celebrating Lewis's memory.

It's unclear whether Lewis's choice of a fixed-gear bike—a bike that's hard to stop on hills or in emergency situations, even for the most strong and experienced rider—contributed to his death. Is outlawing brakeless, fixed-gear bikes a solution? I don't think so. More safety—in the form of separate bike lanes; better, more visible lane markings; and traffic signals that don't favor drivers at the expense of everyone else's safety—is badly needed.

On the other hand, it's up to bikers to look out for cars, because bikers are the ones who always lose in bike/vehicle collisions. Fair? No. Drivers should be more aware of cyclists, too—much more aware.

But looking out for cars—hell, assuming they don't see you and don't care if they hit you—is how you avoid being hit. To quote cyclist Denny Trimble on the Point 83 forum: "Do yourselves a favor and be ready for that truck to turn right any time you're passing traffic in the bike lane. Same goes for oncoming cars turning left—after getting hit by one of those, I'm predisposed to think they're all out to get me." recommended