Jul 22 2014

Why Smart Cyclists Go With the Flow
by Marcos Netto, TNO Southern Hemisphere Correspondent

A recent piece by Marcos Netto, TNO‘s Southern Hemisphere Correspondent, mentioned an article on cycling safety that he’d written for the Itati corporate blog. (Marcos is a director of Itati, a Brazilian mineral water company.) It’s a good article on an important subject, but unfortunately for North American and British readers, the blog is in Portuguese, and the Google translation leaves much to be desired.

We figured we could do a better job than Google did, and with Marcos’ invaluable assistance, we have. Here’s the result:


I see a lot of cyclists who ride against the flow of traffic — in the States they’re often called “salmon cyclists” — and when I ask them why they do what they do, they often say they feel safer when they can observe cars coming at them. This, they claim, makes it easier for them to avoid collisions. And these are collisions from which the cyclist always comes out second-best.

It’s a common sense argument, I suppose, but like a lot of common sense arguments, it’s wrong. Dead wrong. And to make matters worse, going against the flow is also inefficient. So let’s take a look at the case for going with the flow. To begin with …

Riding With Traffic is Faster.  Cyclists who go with the flow slow down, swerve, and stop less often. That means they maintain a higher average speed and arrive at their destinations more quickly. If you’re just riding to ride, this probably wouldn’t matter. But if you’re riding to go somewhere — to a job or an appointment, say — it does.

And that’s not all.

Riding With Traffic is Also Safer.  If you go with the flow, you’re part of the traffic, not an obstacle that traffic has to detour around. According to John Forester, a trained engineer whose book Effective Cycling (MIT Press, 1993) became the bible of the Vehicular Cycling movement, cyclists riding with traffic are about five times less likely to be struck by cars than riders who go against the flow. And while some of Forester’s conclusions have been challenged in recent years, this one has stood the test of time. According to Bruce Mackey, Nevada (US) State Education Officer for Bicycle and Pedestrian Safety, 25 percent of accidents involving cyclists in the United States can be attributed to the cyclists’ decision to ride against the flow of traffic.

And why is this? One reason is obvious:

Riding Against Traffic Gives Cyclists and Drivers Less Time to React.  Rear-end collisions — collisions attributable to a motor vehicle striking a cyclist from behind — make up less than four percent of total collisions, yet cyclists who ride against the flow of traffic often explain their actions by citing a fear of being hit from behind. But let’s look at the realities. It requires time for both cyclists and motorists to recognize that a collision is imminent and take appropriate action. Wrong-way cycling robs both cyclist and driver of critical seconds. If a cyclist traveling at 12 mph approaches a car head-on when the car is traveling at 36 mph, cyclist and car are closing at a combined speed of 48 mph. This doesn’t give either party much time to react to an impending collision. On the other hand, if the cyclist is moving with traffic, the car closes the gap at only 24 mph — half the closing speed in the previous scenario, when the cyclist was going against the flow. This gives the motorist twice as much time to brake or steer around the cyclist. And those seconds can make all the difference.

The bottom line? Going with the flow improves your chances of getting to your destination in one piece. And you can improve the odds even more by maintaining good situational awareness. This means using a mirror and keeping your ears open.

OK. So far, so good. But suppose the worst happens, and a car hits you? Well, you’re still better off going with the flow, because, all other things being equal, …

Head-On Collisions Are Worse Than Being Rear-Ended.  This is physics, pure and simple, and it follows from the analysis in the previous paragraph. Closing speed determines the energy of collision. And that energy increases as the square of velocity. So in the unhappy event of a collision between a car and a cyclist, anything that reduces the closing speed at impact is good. In our earlier example, the wrong-way cyclist approached the car at 48 mph, whereas the car closed with the cyclist who elected to go with the flow at only 24 mph. If a collision had been inevitable, the wrong-way cyclist would have been subject to much higher forces than his go-with-the-flow counterpart. This is not good news for the wrong-way guy.

Nor is he (or she) any better off when turning.

Riding With Traffic Lessens Risks in Turns.  One of the most common causes of collisions is the motorist who makes an abrupt crossing turn in front of a cyclist, and here, too, the wrong-way cyclist has less time to react. Of course, it’s better if the motorist sees the cyclist, slows, and then turns behind her. And this is more likely if the cyclist is in the lane, going with the flow of traffic. (Forester recommends “taking the lane” as a matter of routine, arguing that this improves the chances that the cyclist will be seen. It’s not bad advice, though the strategy isn’t foolproof. If a driver’s eyes are on his smartphone, for instance, it doesn’t matter where the cyclist is. She’ll be invisible.)

“Invisible” cyclists are also at risk in intersections, since …

Motorists Can’t See Cyclists Who Aren’t Where They’re Looking.  Now this is common sense. And it’s important, because a high proportion of car-bicycle collisions happen at intersections. When motorists approach an intersection they scan the road in the direction of oncoming traffic. They don’t expect cars to travel the wrong way in a lane, so they don’t look there. Take a freeway entrance ramp, for instance: When a Brazilian or US motorist merges with the high-speed traffic, she looks to the left for a gap in the line of oncoming cars, not to the right. Much the same thing happens at intersections. A driver preparing to enter an intersection looks left to see if the near lane is clear. Then she looks right, to see what’s coming in the far lane. She doesn’t expect to see cars going the wrong way in either lane, so she doesn’t look for them. And that means she won’t spot a wrong-way cyclist, either.

Of course, there are all sorts of intersections, and these include …

Driveways and the Entrances to (and Exits From) Parking Lots and Garages.  Here, too, motorists look only in the direction they expect oncoming traffic. The wrong-way cyclist is invisible, and any last-minute attempt on her part to take refuge on the sidewalk is likely to be frustrated by parked cars.

And while we’re on the subject of parked cars, …

Drivers Don’t Look for Wrong-Way Cyclists When They Leave Their Cars, Either.  Many motorists don’t bother looking in the side mirror before they open their car doors, but almost no motorist checks for wrong-way cyclists who might be coming toward him. The result is likely to be painful for both parties, but the cyclist will probably get the worst of it.

Speaking of getting the worst of it… So far the cyclist has born the brunt of any collision, but when a cyclist collides with a pedestrian, both parties are likely to be injured, and …

Pedestrians Don’t Expect Wrong-Way Cyclists.  Walkers, like motorists, look in the direction from which they expect danger to come. They aren’t likely to spot a wrong-way cyclist — until it’s too late, that is.


This is a lot to take in, I know. But it can be summarized in one sentence: Cyclists who want to minimize their risk of collision are well advised to …

Behave as if They Belong on the Road.  While there are no guarantees, a cyclist’s chances of getting through the day without mishap can’t help but be improved by being seen — and by being seen to behave in a predictable way. Such “good manners” have another benefit, too. For all the reasons outlined above, the wrong-way cyclist’s day is a series of narrowly averted disasters. His journey from Point A to Point B is punctuated by a succession of panic stops and sudden swerves. These slow him down. And that doesn’t help him get where he’s going, on time and unruffled. When all is said and done, therefore, going against the flow is tiring, difficult, and dangerous. Just ask a salmon.

Of course, salmon don’t have any choice in the matter. But you do. You’re smarter than a fish, aren’t you? Sure you are! So make it a habit to go with the flow.

A Hard LessonDefinitely the Wrong Way to Start Your Day


Sources and Further Reading


Questions? Comments? Just click here!

Jul 21 2014

Bike Monday for July 21, 2014: Free Rider

The olfactory landscape of New York’s Borderlands is changing. Not so very long ago, balsam poplar, apple blossom, and sweet clover were the dominant notes. But nowadays the gentle breeze is more likely to waft a nauseating potpourri your way, with greasy two-stroke exhaust and Febreze being the principle components. When the stink gets to be too much to bear, I flee to one of the few remaining enclaves of good scents: a stretch of town road as yet undiscovered by schlock developers and lawn-care companies.

It offers only the briefest of respites, of course, but I enjoy the opportunity to breathe free while pedaling along at an easy 16 mph and listening to a mixed chorus of bird call and frog song. Still, as Thoreau rightly observed, “a fault-finder will find faults even in paradise,” and I’m duty-bound to report that my little paradise boasts a resident population of bloodthirsty imps. Fortunately, I was able to persuade one to interrupt her accustomed meal long enough for me to snap her picture. And here it is:

Lady of the Flies

She’s not a companion I’d go out of my way to share a ride with, I admit, but if I’m forced to choose between Febreze and flies, I’ll take the flies every time. And this deerfly drew my attention to the sorry state of my bar tape, too. That’s worth a little blood money, I guess.


We love our bikes, right? And we never tire of looking at them. At least I don’t, and if I’m to judge from what others tell me, I’m not alone. So each Monday I’ll publish a bike-related picture. Most of the time it will be a photo, but don’t be surprised if a few drawings and paintings get added to the mix from time to time. I might even include a sculpture or two. (OK. A photo of a sculpture.) Anything, in short, that evokes the world on two wheels. And don’t be shy. If you have a picture you’d like to share, just email it to me. I’ll do the rest.

Questions? Comments? Just click here!

Jul 19 2014

Time to ReVisor Your Thinking?

On the top shelf of the gear closet a curious household ornament collects dust: the helmet that Farwell was wearing when a dog sent him flying over the handlebars at 20 mph. Farwell won’t entertain any notion that it’s time to throw it out. After all, the helmet did its job. When his head slapped against the asphalt, Farwell was stunned senseless. Not good. But he wasn’t down for the count. He came to after only a few minutes—during which time the local motorists were considerate enough to detour around his inert form—and he soon remembered both who he was and how he’d come to be lying in the middle of the road. Then he staggered off, out of harm’s way, bloody but alive.

Alive, yes. But as the free-flowing blood attested, not uninjured. And the most serious of his many wounds was the neat, almost surgical, excision of the lower lid on his only useful eye. Luckily, the duty surgeon at the little hospital where Farwell ended up had a real flare for reconstructive work. His repair job was a complete success, both functionally and cosmetically, notwithstanding the fact that much of the cutting and stitching had to be done without benefit of anesthesia. It’s a good thing the doctor had a patient patient, I guess.

And that patient has always blamed the wire frames of his glasses for the injury to his eyelid. There was certainly a lot of blood on the twisted metal remnants to support this conclusion. But then there was a lot of blood on everything—eyeglasses, helmet, clothing, even the bike. And after inspecting Farwell’s helmet closely I’ve come round to the idea that it was probably the visor that sliced his eyelid off.

See what you think. Here’s where the helmet shell separated from the foam liner at the front, near one of the visor’s anchor points:

What an Impact

And here’s a close look at the right front quadrant, where the force of the initial impact cracked the foam liner:

Scraping By

Needless to say, Farwell is glad he was wearing this helmet when the dog took him down. I am, too, since I spent several years of my life caring for the victims of head trauma, most of whom were incapable of doing so much as feeding themselves. I think of them often, particularly when I see some blithe spirit weaving her way through several lines of impatient motorists at a congested intersection, her long hair flying free. If something—a car door that opens without warning, say, or a pedestrian sprinting across the road (or a darting dog)—brings her crashing down, I doubt that those free-flowing tresses will offer her as much protection as Farwell’s helmet did him. But I digress.

Now take a look at what remains of Farwell’s visor:

Sharp Visor

It shattered on impact, and that ragged point you see is every bit as sharp as it appears:

Get the Point

Was this the knife that whittled Farwell’s lower eyelid away? It was crusted with blood when he brought the helmet back from the hospital, but at the time neither of us made the connection. On further consideration, however, it now seems the likeliest candidate. I suppose we can never be sure, but I do know one thing: I no longer trusted my own visor. So I removed it from my helmet. In future, a brimmed cycling cap worn underneath the helmet will shade my eyes when the sun is low—and absorb the sweat from my pate when it’s high. That’s more than my visor ever did.

What about it? Are you ready to revisor your thinking, too?

Further Reading


This article is an update of one originally published on May 15, 2012.

Questions? Comments? Just click here!

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