[Ken Kifer's Bike Pages]
ARTICLE: Wrong Way Cycling
Why people bicycle on the wrong side of the road, why the pedestrian "rule" does not work for cyclists, and how riding against traffic increases the risk of collision.

Where are wrong-way cyclists found, and why do they defend their behavior? Is the pedestrian rule always right for pedestrians? Why can the pedestrian rule be fatal for cyclists? How is wrong way bicycling dangerous for other cyclists? Why does a wrong way bike rider get passed more often? Why are turning vehicles more dangerous to the wrong way bicyclist? Why does the wrong-way rider have less time and space in which to react? Why is closing speed so important? How are the braking distances and impact forces affected by closing speed? What are the legal implications of riding on the wrong side? What advantages encourage riding on the wrong side, and what are better solutions?


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Wrong Way Cycling

In traveling around the country, I meet wrong-way cyclists in nearly every state. When I tell them they are on the wrong side of the road, they generally become immediately hostile. They have heard it all before from other cyclists, they were taught otherwise, and they don't understand why riding on the wrong side is dangerous.

The Pedestrian Rule

Most people who are riding on the wrong side are following the old pedestrian rule "walk facing traffic." There are two reasons why this is a good idea for pedestrians. First, they can see on-coming vehicles easily, and second, they can readily step out of the highway. Nonetheless, I don't think this is always the best rule, even for pedestrians. For example, nearing the top of a hill, the time in which to see the on-coming vehicle gets shorter and shorter. So, when I am walking,  I always swap sides before I get too near the top. I do the same thing when walking around tight bends in the road. An even better idea, which I do whenever possible, is to walk on whichever side gets me entirely off of and away from the road.

Why the Pedestrian Rule Doesn't Help Cyclists

For cyclists, the pedestrian rule can be a fatal mistake. They are traveling much faster than pedestrians, so they have to react much quicker, but getting off of the road quickly is sometimes difficult, dangerous, or impossible. Often, the wrong way cyclist does not get off the road at all, yet pedestrians are required by law to step off of the roadway.

The Danger for Other Cyclists

Staying on the road creates a danger for other cyclists. One danger that a cyclist faces is passing the wrong way cyclist while other vehicles are passing in the same lane. But an even greater danger is that the wrong way cyclist causes passing vehicles to break the law. The law says that you can't pass on-coming traffic in the same lane. So, if the wrong way cyclist stays on the road, he is forcing every passing motorist to either break the law or to come to a complete stop. When the motorists become used to breaking that law, they think nothing of passing vehicles while cyclists are approaching in the opposite lane. Although I've never had anyone hit me (or I wouldn't be alive), having a car miss by inches at 70 mph is a scary experience.  And the number of cases of this happening has been increasing.

More Passing Vehicles

There are many good reasons for not riding on the wrong side.  The simplest perhaps is the increase in the number of passing vehicles.  For instance, traveling in the same direction as 30 mph traffic at 15 mph halves the number of passing vehicles while traveling against the same traffic at the same speed increases the number of passing vehicles by 150%.  So, the number of passing vehicles increases by three times. The chart below provides the figures for various speeds.

The Increase in the Number of Motor Vehicles Passing, Wrong Side vs. Right Side
Motor Vehicle Speed  Bicycle Speed 10 mph Bicycle Speed 15 mph  Bicycle Speed 20 mph
20 mph 3 times 7 times --  
30 mph 2 times 3 times 5 times
40 mph 1.6 times 2.2 times 3 times
50 mph 1.5 times 1.9 times 2.3 times
60 mph 1.4 times 1.6 times 2 times

Three Wrong-Way Dangers

Now, there are three dangers to the wrong way cyclist. These are the turning danger, the limited time and space in which to react, and the closing speeds.

Turning Vehicles

First, when riding on the wrong side, the danger of getting struck by turning vehicles or by vehicles pulling out onto the road is much greater. The problem here is that when the motorist scans the road, he's looking for vehicles traveling on the right side of the road and in the normal position and does not expect or bother to look for wrong-way cyclists. In keeping with this turning danger, cycling in the correct direction on the sidewalk is nearly twice as dangerous as cycling in the correct direction on the road, but cycling in the wrong direction on the sidewalk is even more dangerous than cycling the wrong way in the street, because the cyclist is even less visible to the motorist. See the Dilemmas of Bicycle Planning.

Less Time to React

Second, there is less time and distance for the motorist and cyclist to react when the cyclist is on the wrong side.  When approaching a cyclist from behind, the motorist can slow down and pass when doing so is safest.  However, when driving towards an approaching cyclist, the motorist has a more restricted choice of passing places and less time in which to react.  The cyclist also has more time to react and can speed up somewhat when being passed from the rear; he has little ability to determine where he will be passed and much less time in which to react when being passed from the front.

Let's use some figures to make the matter more clear. Let's assume that the motor vehicle is moving at 60 mph or 88 feet per second and the bicycle at 15 mph or 22 feet per second. Let's assume also that the motorist first notices the cyclist from 330 feet away, a not unreasonable distance, especially on a winding or busy road. If the cyclist and motorist are approaching each other, it will take them just three seconds to meet, and a minimum of 3/4ths of a second will be lost in reaction time. Since the bicycle is traveling at 22 feet per second, the cyclist will have less than 50 feet in which to get off of the road. If that 50 feet of road includes some barrier that prevents the cyclist from leaving the roadway, then he must play chicken at close distances and at 75 mph (if the motorist doesn't slow down). If the motorist does try to stop, the cyclist will have a little more space in which to get off the road, but very little more, as it will take the motorist 280 feet to come to a complete stop. On the other hand, with the same conditions and the bicycle moving away from the motor vehicle, it will take the motorist five seconds to cover the 330 foot distance between them. In that five seconds, allowing for reaction time, the cyclist will have nearly twice the time and twice the distance in which to leave the road, provided that the motorist never slows down. If the motorist should pass without slowing, the combined speed will be 45 mph. If the motorist slows down, he has a good opportunity to pass safely. In my experience, the motorist almost always slows down to pass safely when I am traveling in the same direction.

Faster Closing Speed

Third, the closing speed is much more dangerous when cycling against traffic. Closing speed is very important when we consider that for pedestrians there is a 2% chance of getting killed when the impact speed is under 18 mph and a 94% chance of getting killed when the impact speed is over 30 mph. (These figures come from Pedalling Health.) We can chart these speeds (closing speeds over 30 mph marked in red):

Closing Speeds Depending on Motor Vehicle Speed and Bicycle Speed
  Bicycle Speed 10 mph Bicycle Speed 15 mph  Bicycle Speed 20 mph
MV Speed  Right Way Wrong Way  Right Way Wrong Way  Right Way Wrong Way
20 mph 10 mph 30 mph  5 mph 35 mph  0 mph 40 mph
30 mph 20 mph 40 mph 15 mph 45 mph 10 mph 50 mph
40 mph 30 mph 50 mph 25 mph 55 mph 20 mph 60 mph
50 mph 40 mph 60 mph 35 mph 65 mph 30 mph 70 mph
60 mph 50 mph 70 mph 45 mph 75 mph 40 mph 80 mph

Greater Impact Force and Braking Distances

In addition to the problem of closing speeds doubling or more, we also finding increasing problems with impact forces and braking distances. When the closing speed doubles, the force of impact increases by four times, and when the closing speed triples, the force of impact increases by nine times.  The same figures are approximately true for braking distances as well.  The following chart combines the feet of braking distance plus the distance lost to reaction time (about 3/4 second if the driver is alert).

Auto Braking Distances Depending on Motor Vehicle Speed and Bicycle Speed
  Bicycle Speed 10 mph Bicycle Speed 20 mph
Auto Speed  Wrong  Way  Right  Way  Wrong  Way  Right  Way
20 mph <46 feet  87 feet  0 feet 140 feet
30 mph  46 feet 140 feet <46 feet 201 feet
40 mph  87 feet 201 feet  46 feet 281 feet
50 mph 140 feet 281 feet  87 feet 367 feet
60 mph 201 feet 367 feet 140 feet >367 feet

This chart clearly shows that riding on the right side at least doubles the safety margin in feet and usually increases it much more.  Because a cyclist is small and may look like a road sign or pedestrian at a distance, the motorist might be fairly close before recognition sets in, even during clear weather on a straight road during the day.  If say the motor vehicle is traveling at 60 mph and the cyclist is going the wrong way at 10 mph, the motorist has got to start braking 367 feet away in order to stop in time. Under many conditions, the motorist is not going to recognize or even be able to see the cyclist 367 feet away.

Actually, the odds are even better for riding on the right side than this chart suggest.  You see, the motorist has to be able to stop for the wrong way cyclist, but he only has to slow to the cyclist's speed for the right side cyclist.

The Legal Issue

Finally, the legal position of the person riding on the wrong side is very different from the person riding on the right side.  Assuming an auto accident caused by a swerving car, the cyclist on the right side is innocent until proven guilty while the person on the wrong side is automatically guilty.  If the cyclist on the right side gets struck, the motorist has to pay the cyclist's damages and hospital bills unless there was some clear fault on the part of the cyclist. It the cyclist on the wrong side gets hit, the cyclist ends up paying any damages to the motor vehicle, unless the motorist was even more negligent and maybe not then.

The simple truth is that as a cyclist you have all the rights and responsibilities of someone driving a vehicle.  Check your state traffic laws; a quick source is Bicycle Laws in the United States.

A Summary of the Dangers

So, when cycling on the wrong side, the chances of not being seen by motorists who are turning or pulling out increases, the number of passing vehicles increases, the time needed to avoid an on-coming vehicle decreases, the chance of finding a safe place to pull off the road decreases, the speed of impact increases, the braking distance decreases, and the liability lies with the cyclist.

Some Advantages to the Wrong Side

Now, I'm sure the reply to all of these arguments is that of staying constantly alert and not depending on the motorist to do the right thing.  And I agree; that's the policy I use in traveling with traffic. If riding with the traffic is like playing Russian roulette (quite an exaggeration), then riding against traffic is like playing Russian roulette with five bullets in the chambers.

The one good reason for riding on the wrong side is the enhanced ability to see the approaching motor vehicle. However, there is an answer to this problem as well: buy a rear-view mirror. There are mirrors that mount to the frame, to the handlebars, to the down tube, to the brake, to the eyeglasses, and to the helmet. If you want to, you can buy several mirrors and attach them all over your bike. Cyclists with more experience don't generally use mirrors because they can turn their heads without running the bike off of the road, but there is certainly no stigma against using one, and many cyclists use mirrors all of their lives. I also use my ears to hear approaching motor vehicles; I can hear them long before they're visible.

There are two other so-called advantages for riding on the wrong side that I have also heard. 1) The shoulder is wider over there.  This doesn't add up because people cycling on the sidewalk going the wrong way are in even more danger than those traveling the wrong way in the road. Actually, it's generally safer to be riding in the traffic lane than on the shoulder in order to be more visible. See my article on riding in traffic.  2) It's safer on the wrong side when a low sun is blinding the motorists.  Pulling off of the road when a vehicle gets close is a good solution to this problem and similar visibility problems, such as riding in the fog or at night on a winding road, but riding on the right side still gives you much more time in which to pull off.

For further advice on how to ride safely on the road and how get avoid getting struck from the rear, see my other articles in this directory.


Why bicycle riders should not ride on the wrong side of the road  Bob Bayn provides his list of reasons along with diagrams demonstrate the problem.

FAQ'S: Legal and Policy Issues  BicyclingInfo supports vehicular cycling, including riding on the right side of the road.

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