Bike-o-nomics: Of Social Norms, Externalities, Tipping Points and Bike City, USA

Hawthorne Bridge bike traffic.
(Photo © J. Maus)

[Yes, back to the o-nomics thing...]

This is a post about social norms, externalities, tipping points and Bike City, USA. It was inspired by the many complaints in the paper, among friends, on Twitter, etc. about bad biking behavior in Portland. As I am on the Springwater Corridor path between Sellwood and Downtown constantly, I see bad bike behavior constantly - almost always on the part of fast and impatient bikers.  But bad biking behavior is everywhere in Bike City, USA and this post will argue that we have reached a point where our approach to regulating biking in the city has to change.

First let's fix ideas with a primer on the economic principles of which I speak.

Social Norms: Social norms are just that - behavioral standards that are set by society but are generally unenforced by an authority.  Consider the lesson you were taught as a child not to stare at strangers.  Your parents probably told you this and maybe even scolded you once or twice for doing so.  Over time this became part of the set of bad behaviors that one doesn't engage in as a member of polite society in good standing.

But why do we continue to behave in this way even when we grow up and our parents no longer have authority over us?  I mean, there are many interesting people in the world and we would get a lot of enjoyment from closely studying their behavior/appearance/manners from afar.  And the real cost is basically nil - perhaps a dirty look, but no real sanction is involved.  So from a optimal decision making standpoint, the best thing to do is to stare away when it pleases you.

We don't because the social norm of good behavior has been ingrained into our psyche and we do feel a psychic cost from violating the norm.  So, in general, people don't stare.  Social norms work fine in cases such as this, when there is no monetary gain to engaging in boorish behavior.  A simple ingrained lesson in etiquette can sustain a no-staring equilibrium.

They also work fine when there is a self reinforcing cost and benefit system like the norm of driving on the right side of the road.  Once we all agree to this norm, the cost of violating it is severe and so we all find it in or individual best interest to continue to drive (or ride) on the right.

The problem comes when there are real payoffs to violating the norm.  For example, we could try and regulate the speed of traffic through residential neighborhoods by norm, but as each driver gets a direct benefit from going too fast, many will violate the norm. So activities with substantial payoffs need enforcement and thus we move beyond norms and into laws, speed-bumps and enforcement.

Externalities: This one is more straightforward - the violating of norms of laws comes with it an expected cost born by the bad actor him or herself, but it also imposes a cost on other people that the actor doesn't have to pay.  For example, the person who speeds through a neighborhood imposes a cost in terms of the reduced safety of residents of the neighborhood, but the driver only factors in the real expected cost of getting caught or causing an accident.  In terms of biking, bad behavior on part of some bikers in the form of going too fast, passing dangerously, ignoring traffic laws, etc., makes every other biker and pedestrian less safe.  And not just form the direct consequences of the bad bikers actions, but indirectly as well, as drivers of cars become frustrated, confused and upset, they begin to behave badly (mostly more aggressively) as well.

Tipping Points: Malcolm Gladwell has popularized the idea, but economists have been talking about this for years.  We often refer to a type of tipping point that includes external costs or benefits a threshold externality: this is when just a tiny bit of extra activity with which an externality is associated causes a huge jump in the externality itself and adds substantial additional costs to everyone else.

In this case, when there are only a few bikers on the roads, and bike lanes and paths are uncrowded, having 5% of bikers behaving badly doesn't matter that much because the external cost is basically nil. But once you reach the point where there is crowding on the roads, lanes and paths, one bad biker can impose substantial risks to others.  In fact I submit that the external costs skyrocket while the internal costs rise only marginally and the benefits rise as well.

Take the Hawthorne Bridge as an example: when there are only a few bikes and pedestrians on it, riding crazy imposes almost no external cost but also doesn't have that much benefit - one doesn't have to be dangerous to go fast.   But when crowded, riding crazy by one rider substantially increases the risk to others and, as congestion means slower traffic, dangerous riding has a real benefit - being dangerous can get you across much faster.

Bike City, USA: Portland, Oregon.

So here is my thesis: Portland has reached a point in its evolution as Bike City, USA where biking has become so popular that we are reaching a threshold in the bad biking externality.  This represents a tipping point because as the city tries to encourage more riding it will find itself constrained by a small percentage of bad riders who impose a large cost to others and this will dissuade new riders from emerging.

Essentially, save for a few times when the Police monitor a specific stop sign and issue citations for rolling stops, biking in Portland is regulated by social norms.  This is fine when the benefits to violating the norms are small, but congestion has now raised the real benefit for violating norms, and it is quite possible that bad biking behavior will only increase in the current system.  We may be at that point where they can no longer rely on social norms to regulate bike traffic.

Thus, it may be the case that regulations and enforcement need to be increased.  Portland may have to come to the realization that in order to make continued progress in getting people to choose a bike instead of a car, more direct intervention into regulating and enforcing these biking regulations is necessary.

I don't know precisely what is appropriate but starting with hand or coaster brakes and a bell as required equipment seems a good idea.  Regulations that mandate the use of said bell, prohibit passing unless safe, maintaing a safe speed and prohibiting earphones are other good ideas.  Some of these are already on the books so having an active enforcement regime is the logical next step.

The good news is that a little regulation and enforcement could go a long way for, if a few bad actors impose large negative externalities, than cracking down on the behavior of those few will have large and immediate benefits.

I wonder if Portland could set up a team of quasi-official bike police who are not real police and have the right only to issue citations for moving violations and improper equipment.  This would be a relatively inexpensive way to get on top of the problem.

In any event, the tipping point may be near and Portland would do well to think seriously about how it deals with bikes.