Why Transportation Nudges Are Stupid
An ad that tries to “nudge” people into safer behavior through, as Streetsblog puts it, “one of the all-time worst examples of pedestrian shaming.”
I travel a lot for Strong Towns and frequently wind up in a rental car. I place my bag on the passenger’s seat next to me because then I can easily reach a snack or Kleenex or whatever. It’s probably 25 pounds, yet quite often I get the continual ding telling me that someone in the car doesn’t have their seatbelt on. I’m nudged to reach over and put the bag on the floor, fulfilling the wishes of some data scientist somewhere who found a correlation between that behavior and a 1.264% reduction in automobile crashes.
I have grown to hate the nudge concept, especially as it’s being applied by people who have likely never taken a course, let alone read a book, on human psychology, behavioral science, or cognition. I especially hate the stupid ways in which the nudging approach is being used by engineers, public safety officials, and others in the transportation professions.
I read Nudge: Improving Decisions about Health, Wealth, and Happiness by Richard Thaler and Cass R. Sunstein a couple years after it was published. It basically takes the insights of Daniel Kahneman, and his colleague, Amos Tversky, as expressed in Kahneman’s book Thinking, Fast and Slow, and simplifies them to some real-world applications. Its novel insight is that well-intentioned people can use tricks that marketing people have long intuited to nudge people to do things that the well-intentioned want them to do.
For example, we want people to eat healthier, so if we label foods at a buffet with green (healthy), yellow (questionable), and red (unhealthy) dots, we can nudge people to eat healthier. I experienced this at Google—they have applied nudge thinking to their cafeterias—and I also experience it, albeit in a different and more aggressive form, from my wife at the dinner table. I feel a bit of restraint in both situations, especially at the point where success is measured, but admit to sneaking a bit of chocolate later on when nobody’s looking.
That’s not to say that all nudge insights are simplistic and not a genuine measure of human behavior. One example in Nudge was about changes to a tax collection letter. You can imagine such a letter being boring or threatening, but when the letter was reworked to begin with a statement along the lines of, “85% of UK residents pay their taxes on time,” collections went way up.
The simple phrasing nudged more people to send in their late taxes than otherwise would by playing on natural human feelings of obligation to the community. If you’re a member of Strong Towns, you might see similar language in renewal communications that suggest that 65% of all members continue to support the movement financially after one year. It’s a true statement that also communicates how we’re all in this together (and, as such, it does increase donation rates).
The question with the tax collection letter is: How effective will it be the second time around? And this is where I’d like to transition to transportation because so many of the nudges we get from the transportation profession are more like gimmicks, at best.
At the extreme are the (often unsanctioned) interventions people do to paint large potholes or other optical illusions on the street, or (sanctioned) to put up a new sign or cone in a place where the goal is to get people to drive slower. The 20 mph speed limit, sans any other change, has this same effect. The nudgers go out and measure the world after their intervention and, lo-and-behold, that crosswalk that now looks like a three-dimensional, psychedelic piano prompts drivers to slow down. They rarely come back a month later and measure what happens when everyone adjusts to the change.
That’s because we all know what happens. The novelty or surprise wears off. The intervention becomes part of the unnoticed background. Things go back to normal.
I’m aligned with the goals of Vision Zero efforts—and who isn’t—but I struggle with the way it is implemented. The part of Vision Zero funding that isn’t supplementing law enforcement budgets or paying to expand highway clear zones, and stroad intersection buffers often goes to nudging the public through information campaigns.
Last year, at my community homecoming football game, law enforcement personnel fired t-shirts into the crowd. The shirts had a Toward Zero Deaths message (Minnesota’s slightly less ambitious version of Vision Zero) and were part of a campaign to improve driver safety. Sure, the announcer simultaneously read a message about texting and driving, but look at the crowd; does anyone legitimately believe this nudge is going to alter the behavior of a driver who gets a text they consider important while driving in an environment they consider safe?
The Start Seeing Motorcycles campaign is another example, as if anyone consciously tries to not see motorcycles. As a nudge, this messaging spends a lot of time on behaviors that are not really nudgeable. Obviously, people don’t struggle to see motorcycles because they have an indifference to seeing them. They struggle to see motorcycles because motorcycles are small, easily fit within blind spots, move surprisingly quick, and make up a small proportion of a traffic stream (especially in cold weather states like mine), and so their presence is generally unexpected. This video is particularly gratuitous.
Billboard messages and magazine ads fit broadly into this category of stupid nudges, messaging that might feel compelling in a laboratory or a focus group, but has a dubious connection between the nudge and the desired behavior. There are numerous cringey examples of shaming and victim blaming in this genre, but perhaps the most offensive are these three exploitations of little girls with tire tracks on their faces, as if seeing that image in a magazine ad, combined with the message “you can’t fix a pedestrian at a body shop,” will do anything to change how people interpret the level of risk in the driving environment. Good Lord, people, she’s a human—a little girl—and not a quantifiable statistic of a traffic unit known as a “pedestrian.” This is disgusting.
A recent article in science suggests that behavioral nudges of this shock and shame variety—displaying death tolls on signs in high-crash areas—actually induces more crashes. The effect was small (and I question some of the methodology here, especially the cause-effect relationship), but even if it’s not a replicable outcome, the important takeaway should be that this kind of nudge messaging doesn't work. It might make things more dangerous, but it doesn’t make things safer.
So, what does work?
Hans Monderman, the great pioneer of shared space, once said, “When you treat people like idiots, they act like idiots.” Nudging works best when it understands and respects human cognition and behavior, but transportation nudges don’t do that. Transportation professionals think drivers are idiots and so they treat them like idiots. This is why, with traffic deaths going up, the professional response is to blame the user, to identify all the ways that deviant humans become reckless drivers.
This is not only insulting, it’s dangerous.
Want to learn more about what we actually need to do to fix our broken transportation system?
The way we nudge people to safer roads isn’t to change their thinking, it’s to respond to their behavior. Nudging isn’t about trying to fix people’s brains, to make them “better” or more perfect humans. It starts with acknowledging that humans are flawed, irrational, prone to error and faulty assumptions. They are, in a word, “human.” If we want to improve safety, we need to design our transportation systems for humans and all their flaws.
When we design streets with wide lanes, we aren’t creating a safety buffer for the theoretical non-reckless driver. Instead, we are giving all humans a false sense of security, one that speed studies demonstrate induces them to drive faster.
When we provide recovery areas, clear zones, sweeping curves, wide turn radii, and other auto mobility enhancements on our streets, we aren’t compensating for mistakes that drivers make by giving them extra room to move. Instead, we are nudging them to take that extra performance enhancement to increase their performance.
When we make it difficult to walk on our streets, especially in situations where we know people will be walking, we aren’t making things safer by suppressing the number of people who walk or cross the street. Instead, we make people on foot largely invisible to drivers, making our friends and neighbors walking or biking the anomaly drivers aren’t anticipating or compensating for.
If we really want to nudge drivers to behaviors that improve safety, we do so by designing streets so that drivers feel insecure, so they have a feeling of tension and anxiety, when they are driving at speeds that are unsafe for that environment. For a typical American street, that is a speed in excess of 15 mph.
Narrow lanes. Remove buffer areas by bringing in curbs. Add separated bike lanes. Bring in street trees. Tighten up corners and curves. In other words, the exact opposite of standing transportation design practice.
Transportation safety officials are trying to get us to stop eating junk food by putting an open package of Oreo cookies on the counter at home and then placing a sign about obesity above the bathroom stall at work. It’s stupid, and it won’t work, no matter how shocking the message is.
Transportation nudges are stupid because they are based on an incorrect understanding of human behavior and cognition. It’s costing us lives and health, destroying our neighborhoods, and wrecking our public budgets. We need a Strong Towns approach to building safe and productive streets.
When trying to make a walkable and vibrant street, urban planners often think in terms of hard infrastructure like road width and crosswalks. But soft infrastructure, specifically flowers and other colorful plant life, plays an important role as well.