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.