Of the many ways that cities try to get drivers to reduce their speed, traditional iterations of the “Slow Down” sign like the ones above may be the most useless, and borderline harmful. These signs often display a disregard for basic wayfinding and legibility, and rely on overly complicated messaging. They’re usually initiated by councillors or mayors eager to allay their constituents frustrations about speeding. And from tiny towns, like Cuyahoga Falls, Ohio, to huge municipalities, like Toronto, Ontario, they’re everywhere. Traffic engineers don’t like them, but they persist in part because it’s borderline impossible to explain to an eager parent why we should not have them. As Tom Vanderbilt points out in Slate, the slightly dismissive term for them is “advisory signs.” The implication is that they’re notes as opposed to orders, with no weight behind them to speak of.
As a designer who sees a new crop of these signs appear across Toronto every year, I react to them with equal parts frustration and confusion. They’re uniformly poorly designed and seem to get destroyed and pulled apart over the course of a few months. How anyone would think these token efforts are going to do much has always baffled me.
Some say these advisory signs are a silly nonsolution to a grave problem. Indeed, a better solution is to design cities and streets that default people into slower speeds and greater awareness. At the same time, there is a tiny but encouraging body of evidence that suggests that, when these signs hew closely to the language of speeding signage and are designed with behavioral principles in mind, they might effectively reduce speed. For instance, one 2001 study conducted in California did find significant reductions in speed due to placement of slow down signs.
If people often disobey formal traffic signage, what chance does unofficial curb signage have of inducing needed behavior change?
Even a small decrease in speed can have huge, lifesaving implications. A reduction in speed from 40 to 30 miles per hour halves the likelihood of fatality or injury resulting from a collision. The caveat: the signs used in the California study look much more like speed-limit signs—which are clear, concise, and coherent—than traditional slow-down signs.
This points to some of the central flaws of slow-down signs: many would fail even a modest accessibility test, with their illegible type, poor contrast, and density of information. Worse, the language of these signs is often labored and presumptuous. Foundational behavioral science tells us that we should be making it easy for people to understand the signs, which means designing for cognitive ease when someone is travelling at 50 mph. How do we do that? One idea is to avoid complicated ideas like, “Kill your speed, not a child.” Even “Children at play” requires a cognitive leap. “Drive like your kids play here” trades on a presumed reciprocity and again requires a bit of mental exertion. If drivers had more time, messaging that appealed to social norms might work (“Most people don’t speed …”). The primary goal should be making, in a fraction of a second, the desired behavior easy to do. To this effect, the most salient messaging is very likely the simplest: “Slow down.”
There’s also dissonance in the contrast between serious messaging and often playful graphics. While dissonance can be useful, in this case it’s not. “It really does seem to trivialize the issue by having them be cartoony,” says Nancy Smith Lea, director of the Toronto Centre for Active Transport, in response to the latest crop of signage (below), which includes line drawings of smiling kids and seniors. “They just don’t convey the gravity of the issue.”
Smith Lea thinks Kids at Play, a Toronto-based nonprofit, has done a much better job with their design and messaging. Borne out of the tragic death of a young girl, the group has manufactured thousands of signs that read, “Slow Down, Kids at Play,” which appear on lawns in Toronto and much farther afield. She’s right that the hierarchy of information and clarity of message is much stronger. But one wonders if the strange silhouette adds clutter to an otherwise clear message.
Finally, the street sign movement is too unofficial. Whether produced by municipalities or citizen groups, there are no formal guidelines for design, language, and placement. And if people often disobey formal traffic signage, what chance does unofficial curb signage have of inducing needed behavior change?
The quickest fix
Slow-down signs would do well to mimic the vernacular of official street signage, according to wayfinding expert Raymundo Pavan. Graphic language should be formal, clear, and follow rules for accessibility, including contrast, size, placement, and number of words. Also unhelpful is the fact that these signs are most often placed low to the ground, requiring drivers to divert their eyes. “When you’re driving, you’re not looking for info below your sightline, you’re looking for things moving,” he said.
The fact that these signs are creative exercises dressed up as traffic signage gets at the nub of the problem. There is little room for flourish in the highly systemized language of wayfinding. And streetscape visual clutter makes almost anything that doesn’t speak the language of signage feel like advertising or typographical noise.
Ultimately, slower streets are an urban-design issue and not something to be left to community groups to solve.
An intermediate fix would be the more behaviorally informed “Your Speed” signs, which have shown promise and are less expensive than full-scale street redesign.
In Toronto, a pilot project tested electronic “Your Speed” display signs at 10 Toronto-area schools in 2014-2015. The signs effectively reduced the speed of traffic and excessive speeding (more than 10 kph above the speed limit) over an 11-month period. There are two big differences between these electronic signs and slow down signs:
#1: Electronic signs hinge on the idea of immediate feedback—you are getting your speed played back to you—which can be a key element of behavior change.
#2: Electronic signs are clearly a product of the law, as opposed to a fellow citizen.
Ultimately, slower streets are an urban-design issue and not something to be left to community groups to solve. The goal is for governments to take street design, and its accompanying signage, seriously by diving into the actual infrastructure changes that would slow speeds and save lives. These changes include everything from wider sidewalks and narrower streets to elevated bike lanes separating pedestrians from the street.
It’s up to behavioral scientists, planners, and citizens to make sure politicians understand the importance of having municipalities shoulder the responsibility of inducing behavior change, instead of leaving the responsibility to citizens. And behavioral science can help, preventing inane confusion by making sure that new street design and signage proposals work for imperfect humans.