25.9.13

Q: Why Don't Bikers Stop at Stop Signs?

I have a friend who's in the administration at the University of Minnesota, one of the largest schools in the country, and (despite all my insistent proclamations) one of the "most bike friendly" schools in the US. Each time we bump into each other, we have a brief chat about bikes on campus, and how they're out of control. Mostly, I try in vain to defend my bicycling brethren about their bad behavior...

It's not an uncommon topic. As bicycling has been increasing in Minneapolis, especially around the biking epicenter of the University campus, many of the employees, faculty, and others going through the area have come to me with their frustrations about bikes riding on the sidewalk, bikes running stop signs or stop lights, bikes riding in the street, bikes "darting out" and scaring my mom, or bikes parked in various awkward places around the school.

For example, I got an email from my administrator friend the other day, who undoubtedly had experienced another harried drive through campus on his way home from work. He sent me the following brief electronic epistle:
"Driving Your Bike 
By Minnesota law, bicycles are defined as vehicles, so bicyclists must follow the same laws as motorists. To bike safely you need to know Minnesota laws for operating your bicycle.

So why don't bikers ever stop for a stop sign?  I'm trying my best not hit anyone, but it's tough on campus."

Good question! At first glance, the answer is obvious. Bicyclists are hooligans out to terrorize society in general, and people driving cars in particular. There's a lot of evidence for this. Critical mass, blah blah blah.





A: Stopping Destroys All Your Momentum

[A frustrating "stop" sign on the Cedar Lake bike trail.]
Actually, though, the answer is a bit more complicated. The first part of it has to do with efficiency.

Stop signs serve different functions for cars and for bicycles. For someone driving a car, the stop sign is meant to slow you down, to keep your speed in the sub-30mph range, where you won't kill anyone if you hit them, where you still have plenty of ability to make quick decisions. Stop signs are a safety measure, slowing you down from 35 to 5-0, keeping the others neighborhood safe.

For a bicycle, stop signs operate slightly differently. Most bicyclists aren't going that fast in the first place, probably averaging 10 mph in residential or pedestrian-centered areas. Slowing a bicyclist down isn't really necessary for safety reasons. So for bicycles, stop signs serve instead as a traffic flow device, a way to make sure that cars, bikes, and people can pass through an intersection most fairly and efficiently.

That said, the problem with stop signs for bicycles is that, for a bike, there's a huge difference between slowing down to 5 mph and stopping completely. On a bike, when you come to a complete stop you lose all your momentum. It's actually a lot of effort and exertion to regain that last little bit of rolling inertia. On a bike, someone who makes a "foot on the ground" stop at every stop sign will probably work twice as hard to get where they're going as someone who merely slows down to walking speed. If you're on the fence about riding a bike in the first place, this is a deal breaker.

(This is one reason why Dutch-style "green wave" signal timing, where traffic lights are timed to the normal bicycle speed of 10-15 mph, is such a good idea. Bicyclists can keep their momentum, and just cruise to their destinations.)


A: Rolling Stops are Common Sense

[Most bike paths are littered with unwarranted stop signs.]
If you talk to a transportation planner about stop signs, one of the things they'll bring up is how sometimes you can have too many stop signs. In other words, if you try make a street safer by adding more stop signs, sometimes drivers will start to compensate for or ignore them. Engineers call these "unwarranted" stops.

For example, the city of Fort Collins, CO has this to say on the topic:
An unwarranted STOP sign installation reduces speed only immediately adjacent to the sign. In most cases, drivers accelerate as soon as possible, to a speed faster than they drove before STOP signs were installed. They do this apparently to make up for time lost at the STOP sign. STOP signs are not effective for speed control.

For bicycles most of the time, stop signs are even less warranted. In all my interviews and conversations with bicyclists, nobody comes to a stop at every stop sign (except, perhaps, to prove a point). If one is riding through a quiet neighborhood with no cars or people around, you ignore the stop sign.

In fact, Idaho (of all places) has even made this the official state law, now called the "Idaho Stop Law." Here's the description of the law, from the League of American Bicyclists:
When bicyclists in Idaho approach a stop sign they: 
Slow down, and if required for safety, stop. 
Yield the right-of-way to any vehicle in the intersection or approaching, if the approaching vehicle will create a hazard while they cross the intersection. 
Proceed after appropriately slowing and yielding without stopping.
The second rule is a very permissive red light exception. While all other red light exceptions contain language that indicates that proceeding against a red light is only appropriate when the signal fails to detect a bicyclist, the exception in Idaho contains no such language. As with the “Idaho stop” the reason for the law is encouraging cycling by making it easier.

Minneapolis state representative Phyllis Kahn has tried for years to get a similar passed in Minnesota, but to little avail. For bicyclists, this kind of rule is just common sense. It's how the vast majority of urban bicyclists ride in the city anyway, and changing the law to fit actual behavior would be a big step forward to actually fostering an enforceable legal framework.


A: Cars Yielding to Bikes is the Right Thing To Do

[A DIY stop sign in Minneapolis' West Bank neighborhood.]
I'm probably getting onto thinner ice with this one, but there's another case to be made about bikes and stop signs. There's a certain kind of environmental and social justice argument that says that more vulnerable users of the street should always get the right-of-way. In this scheme, pedestrians are at the top of a pyramid of road users, and should the right-of-way in almost all situations. After all, they're the most at risk of injury or death. After that, bicycles should be given priority. They're the second most vulnerable group of people out on the road. Finally, people driving cars should get right-of-way.

This leads to some sticky situations, particularly at intersections. (The debate over pedestrian rights at crosswalks is similar.) In some countries, there's even a legal assumption that the less vulnerable road user is 'at fault' in any crash. But as a general rule of thumb, this is an important principle. Our signalized intersections, street designs, funding priorities, and legal framework should not just equivocate between modes, but prioritize them. A society set up along these lines will be more economically just and more environmentally sustainable than one that prioritizes car driving.


In Practice, Stop Signs Demand Flexibility


These are all theoretical arguments. The lived reality of riding a bicycle in any city is far more complicated. I've written before about DIY Bicycle Infrastructure, and how bicyclists have to make up their own rules as they go along to get by on our inadequate American streets. Here's my personal rule about how to behave at a stop sign:
On quiet residential streets, treat most stop signs as ‘yield: slow down and look for cars and pedestrians’ signs. Treat many stop lights as ‘stop, look both ways, and yield to any traffic' signs. ... [But] caution! Always watch for cross traffic! Yield to car traffic on cross streets.
[The U of MN redesigned a problem intersection, and now many use it properly.]

Honestly, biking in the US means you have to think on your feet. Sometimes, you can completely ignore a stop sign. Other times, particularly in places with a lot of car and foot traffic, you have to pay a lot of attention, actually put your foot on the ground, and yield the right of way.

College campuses like the University of Minnesota present a really difficult riddle for how to behave. There are tons of people walking, driving, lots of buses, and lots of bikes all over the East Bank. What's a bicyclist to do in this situation?

One of the clear lessons from bicycle research is that, as long as bicycles are ignored or shunted into the gutter, people will come up with their own rules. In the absence of a clear common-sense path, bicycling becomes a free-for-all: some people will weave between cars, some will hop into the sidewalk, some will sit in traffic choking on a tailpipe, and some will run through the stop sign.

However, if you have a decent bike infrastructure, the vast majority of people will follow the rules. There was a study about the redesign of a traffic signal in Portland, before and after they installed a separate bike signal for bike traffic. Before the signal, the majority of bikers blew through the red light. After the re-design, which designed safe spaces for bicycles to wait, and gave them a separate signal phase to go safely through the intersection, almost all of the bikers waited at the 'red.' In other words, bicyclists aren't inherently anarchists. If you design a street that actually makes sense for bicycles, people will use it.

So that's the short answer, which it turns out, is a long answer. Bicyclists don't stop at stop signs because it's really tiring, because much of the time it doesn't make any sense, and because in the grand scheme of things, they shouldn't have to.

I hope that helps.




Update:

I received another email from my administrator friend:
Thanks--makes sense.  Except when there is a need to stop, which does not always happen.

I'm thinking of biking on campus--cars are too dangerous.


16 comments:

Anonymous said...

"Idaho (of all places)"

Yeah, yeah.

I just moved to the cities from Boise, actually, and biking was a lot easier there (and not just because of Idaho Stop).

Bill Lindeke said...

i will have to try it sometime, if I ever leave the Twin Cities again.

mplsmitch said...

Generally I think most would agree that running a red light in your car crosses the line into bad behavior. Drivers do it all the time but few would admit to it. The same doesn't hold true for a pedestrian crossing without a walk signal. If there's no immediate danger from oncoming traffic, many of us wouldn't hesitate to cross an intersection on foot and we probably wouldn't view it as bad behavior unless we were being watched by a bus full of kindergarteners. Bikes fall somewhere in between. Motorists want bikes to behave as cars, bicyclists want to behave more like pedestrians.

Jon said...

mplsmitch, as a motorcyclist (recently) and a long time bicyclist (actually I've put more miles on my bicycle then I have my motorcycle, so far) I have to disagree.

The world of two wheels is very different from the world of 0 or 4 wheels.
I find being on a motorcycle must like being on a bicycle in traffic... no one see's me... the people that do see me seem to have an instant disregard for my safety, and in both cases some stoplights refuse to acknowledge my existence.
The benefit of the motorcycle is that I don't need to put the energy in to accelerating... and in the event that I need to get out of the way of a car, I can do so, I'm usually faster than they are.

That being said, there are several comments on how to treat stop signs on motorcycle forums... one foot down or two, or none?
in the MSF training course they teach you how to stop and go, no feet down... a skill I occasionally practice in residential areas with stop signs where there is no other traffic...
And empty but normally busier stop signs I'll put one foot down and then go.
And if there is traffic around, I have to put both feet down, mainly to signal to other motorists that I have completely stopped, because they can't seem to tell if I'm actually stopped, or stopping, until my feet are down.



A friend of mine has both his CDL (for driving 18 wheelers) and his motorcycle endorsement. he jokes that the difference between the courses is that in the Motorcycle class they say "You need to do X because if you don't, you'll die." and in the CDL course it's "You need to do X because if you don't, you'll kill someone." A sentiment that isn't as strongly resonated in the 4 wheel driving course that I've taken (even watching "blood on the highway" at 18 it wasn't so much about driving safe, as it was about being a little afraid of driving)

Klute said...

Some of this makes sense, but mostly it seems to be rationalizing the behavior instead of explaining it.

For instance, the momentum issue. For a bicyclist, you expend far more energy and calories re-starting your bike from a slow or stop. If you are on it for the exercise - as many are - why not maximize this?

Second, why don't bikes stop for peds? That is my pet-peeve. I can desl with a bicyclist blowing through a stop sign on the River Road as they have a clear line of sight to what is going on around them. But, when I'm walking across the street the bicyclists veer around me, totally uncool.

Ultimately, we do need to change our streets and roads to be more accomodating of bikes. But, bicyclists also have to get off their high-horse and stop pretending the rules of the road are left to their individual discretion.

dr2chase said...

@Klute - depends upon what you mean by "stop" for peds.

We seem to have totally different standards for which 12-foot strip of asphalt we're on -- if it's a multi-use path (there's a very popular one that I use often) bikes veering around peds is completely expected behavior, and sometimes involves oncoming traffic, multiple pedestrians, etc. If it's a low-risk ped (adult, no dog), bikes don't even slow down, so some passes occur at 20mph. So, hold that thought -- bikes and peds, not more than 12 feet of separation, passing freely and apparently safely, with exceptions for dogs, children, that sort of thing. And this is 2-way traffic on that 12-foot strip.

In a crosswalk, a single road lane (1-way traffic) is usually about 12 feet wide, especially if it is modern. The only difference is that now the directions of travel are not parallel. I think there are three cases where a cyclist not stopping for a pedestrian might be rude. The first, which ought to be obvious, is if there are children or dogs involved; they're not predictable, they're small and easier to hurt, you should stop.

The second is if the cyclist passes in front of the ped's direction of travel; that's rude, it means that there's obvious common actions (picking up the pace and jogging, maybe to allow a car to pass more easily) that become dangerous. But if the cyclist veers behind the pedestrian, why would this be a problem, except...

The third, is if there is a car following the cyclist. The problem here is that in many cases the cyclist has taken steps (or the bicycle designer has taken steps, see old english three speeds with their distinctive fender pattern) to do things that attract the attention of drivers, which is important for safety. Suppose this works, and the cyclist veers behind a ped, and suddenly the driver is playing spot-the-gorilla (the pedestrian), and sometimes they fail. And failure at spot-the-gorilla is common, we're really good at target-focus blindness. This is not people in cars are stupid, this is people in cars are people.

But if you've got neither kids nor dog with you, and there's no cars around, and the cyclist passes behind, are you sure there's a problem?

A secondary issue might be different standards for "appropriate personal space". American cyclists as a group are somewhat comfortable sharing space with cars, and three feet is considered a legally adequate passing distance. Are you getting three feet, or less? A cyclist argument, and not a bad one, is that if a car going 30 passes them going 15 with a 3-foot clearance, why would you complain if a cyclist going 15 also gives you (only) 3 feet? (*) (Obvious answer: "3 feet is unacceptable, except for cyclists, because hey, they're cyclists and should expect second-class treatment.")

(*) If you do the momentum equations, you can see that the cyclists are being quite generous in this comparison -- if the cyclist is accidentally hit, he could easily be sent flying at 30mph, whereas with equal masses and 15mph cyclist, you should expect about 7.5mph -- when you finally hit the ground, only 1/16th the energy to come to rest.

Adam said...

Good post. I think about this problem a lot and the way I would explain it to drivers is this:

Think about what part of a car is analogous to a bike rider pedaling. The pedaling action is basically a cyclists' motor, it's what drives you forward. Extending this analogy, forward momentum is more or less equivalent to a car idling: it's potential energy. When you lose it, you lose all the energy stored from your previous motor (pedaling) action.

Imagine if we designed cars so that every time they came to a complete stop the motor shut off and the keys jumped out of the ignition. Drivers would use every means possible to avoid coming to a full and complete stop. It would be quite reasonable because that would be extremely annoying.

I don't think this means cyclists should be able to blow through a stop sign at high speed. That's just unsafe. But making them come to a full and complete stop is also pretty unreasonable. It's just not as easy for a bike rider to start moving forward again as it is for a driver to hit their gas pedal.

And as for those people who say, well you're riding your bike for exercise so you should want to expend more energy, well, that's dumb. I ride my bike because it's convenient, fast, easy, freeing, and the way I chose to get around. Burning calories is just a side benefit.

Erica said...

"For a bicyclist, you expend far more energy and calories re-starting your bike from a slow or stop. If you are on it for the exercise - as many are - why not maximize this?"

For the same reason you get better exercise running hard for 15 minutes than walking slowly for 30. Have you ever met anyone whose cardio workout routine is "go really slow and take breaks every 60 seconds?" Probably not.

Constantly stopping and starting slows you almost to a walking pace - you aren't going to get any kind of decent workout that way on a bike.

Anonymous said...

If the bike lobby was as powerful as the car lobby, the law would be similar to speed limits - you only have to stop at a stop sign if 85% of people bicycling stop at a stop sign.

Anonymous said...

There's a great study from Berkeley about the physics. http://socrates.berkeley.edu/~fajans/Teaching/bicycles.html

Jonathan Krall said...

A couple of points to add:
1. Because a cyclist can see cross traffic more easily than a motorist, a "safe" rolling stop on a bicycle is faster than a "safe" rolling stop in a car. But what cars do is considered normal, so cyclists appear to be (more) reckless.
2. There is evidence that cyclists are actually a cautious lot. Data on crashes involving alcohol show that only 1/3 of cyclists in these crashes are drunk.
FWIW, here is my own write up: http://alextimes.com/2013/06/the-bicyclist-as-a-scofflaw-is-a-common-misperception/

Anonymous said...

I'm with you up to the "cars should yield to the most vulnerable road users" bit. My problem with this for cyclists is that it all too often leads to "the wave" wherein a motorist will fail to take their right-of-way at an intersection forcing the cyclist to come to a complete stop to discern the motorist's intention at which point the motorist "waves" the cyclist through. Too late. All momentum is already lost. And I would never assume that a motorist will yield to me in those situations anyway nor do I even necessarily think they should. So all-in-all, I'm much more comfortable with the Idaho stop. Cyclists yield to motorists where it's appropriate and roll on through when it's not necessary to yield. I think this is less confusing to motorists and leads to less resentment about "cyclist privilege." Motorists will still be ticked when they see cyclists roll through stop signs, but too bad. It doesn't impact them and they should just learn about cyclist momentum and motorist traffic calming.

Anonymous said...

I hate "the wave." Holy moly, especially at night or when there's glare on the windshield, and I can't tell if the driver is looking at their phone in their lap, fixing their hair, or thinking that they're being polite by generously waving me through (which I can't see) after I've already come to a complete stop with both feet on the ground. I've wanted to explain this to drivers so many times, that it is their responsibility to behave predictably and follow the rules of the road as well. sigh.... great post. I look forward to improvement in relations between cars and bikes on the road.

Anonymous said...

Dig the analysis. But what happens when two bicyclists meet at a four-way stop. In my experience, even if I have the right of way (i.e., if I am first to the intersection or on the right), the other bicyclist NEVER stops, which infuriates me to no end.

In that situation, the other bicyclist is exhibiting purely selfish behavior insofar as (1) s/he is disregarding my right of way and (2) forcing an equally vulnerable bicyclist to come to a complete stop and lose momentum.

In short, I like your rationale, but I think we, as bike commuters, have to recognize that a significant percentage of bicyclists are selfish/reckless in their behavior, and it is those bicyclists who stick out in the minds of the motorists, making life more difficult for all of us.

Anonymous said...

I would argue that a Stop sign's function goes beyond "slowing down cars". They are there to regulate intersections.

Ryan Davis said...

Klute said...
Some of this makes sense, but mostly it seems to be rationalizing the behavior instead of explaining it.

For instance, the momentum issue. For a bicyclist, you expend far more energy and calories re-starting your bike from a slow or stop. If you are on it for the exercise - as many are - why not maximize this?

Sorry to say I have to bike to get any good cardio exercise after an injury I sustained in the military. Now all my physical therapists have told me to bike instead of running the way I used to. I stayed in shape by running and now that I can't, building the momentum after a full stop isn't helping take the load off my knee.

I may only be one person but I doubt I am the only one that bikes for exercise to ease the impact on the knee or other joint. Its not always about calories, sometimes its about staying active without causing more pain.