The quest to design a better stop sign.

How we get from here to there.
May 25 2010 12:32 PM

Stop!

Is it possible to design a better stop sign?

Check out our Magnum Photos gallery of stop signs.

Illustration by Robert Neubecker. Click image to expand.

In an Internet parody called "The Process," a designer is given a corporate gig with a simple brief: to design a new stop sign. "We're seeing reports that people don't know what to do at an intersection," he is told, and from there it descends in an absurd spiral of tweaks and redesigns, with the designer's creative vision cast against the slow strangulation of groupthink. While the video is a hilarious send-up of the corporate design process, its premise—that designing an effective stop sign is actually a simple task—couldn't be farther from the truth.

In reality, the design of the stop sign, however seemingly settled, is not necessarily ideal. In 1998, for example, there were more than 700,000 crashes at intersections marked—or "controlled," as engineers say—by stop signs. More than 3,000 of these were fatal. Laura Bush's new biography, Speaking From the Heart, highlights the stop sign's role in the fatal crash she caused in high school: She drove through an intersection marked by a stop sign, striking the car of a good friend and killing him. She notes, among other factors, that the stop sign was too small (current signs are larger, and mounted higher, among other changes).

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We don't know what the fatality numbers would look like if modern stop signs were replaced by something else or taken out altogether, but the fact that the sign is at least indirectly implicated in several thousand deaths and hundreds of thousands of injuries every year suggests that traffic engineers should at least look into improving, or replacing, the device.

Indeed, Gary Lauder, a Silicon Valley entrepreneur, was just the latest to propose a redesign of the stop sign during a recent and much-discussed TED presentation. Using the example of a three-way intersection in which a minor road ended in a "T" at a major road, with stop signs all the way around, Lauder calculated that the stopping led to a collective yearly loss in fuel and time valued at roughly $112,000. Why not just use a yield sign on the minor approach? Well, at certain times of the day a queue backs up there, and cars have trouble making the turn. So Lauder proposed a hybrid "stop-yield" sign, simply labeled "Take Turns," paired with the instruction: "If cars are waiting please stop and alternate."

More on the viability of Lauder's design in a moment. But first it's worth considering how we got the sign we have now. Like many forms of traffic instruction, the stop sign has murky origins. It was adapted from railway controls but without rigorous scientific testing. As Kenneth Todd has pointed out, "the traffic control system developed piecemeal. … [W]hen large numbers of automobiles burst on the scene early in the century, political pressures, guesswork, and panic measures served as substitutes for scientific expertise." Indeed, historian Clay McShane writes that in 1914, "Detroit police sergeant Harry Jackson cut the corners off a square sign to create an easily recognized octagonal shape for first red stop sign or 'boulevard' stop." (The signs were controversial: McShane notes that "Illinois courts briefly ruled stop signs illegal in 1922 as a violation of the rights of individuals to cross streets.") By 1927, a rough standardization of the sign was set in place by the American Association of State Highway Officials. An octagonal shape, with red letters on a yellow background. It wasn't until nearly three decades later that the current design—white letters on a red background—was settled upon, in a 1954 supplement to the Manual of Uniform Traffic Control Devices, the operative rulebook for traffic engineers. Is the current design as good as it could be? There are two ways to think about that problem. We must ask: Do drivers see stop signs? And, more importantly, what do they do when they see them?

For nearly a century, it seems, drivers have been ignoring stop signs. In a 1934 study published in the Journal of Social Psychology, for example, F.H. Allport examined driver behavior at an intersection with a stop sign with approaching cross traffic. A majority (75.5 percent) of drivers came to a full stop—no surprise given the imminent danger. But what about in cases where no cross-traffic was visible? Would people still stop? A 1968 study in Berkeley, Calif., published in Law & Society Review, found that just 14 percent of drivers brought their cars to a full stop "without being forced to do so by cross traffic" (the so-called "California roll" was the norm).

No one has more doggedly pursued the question of stop-sign compliance than John Trinkaus, who conducted an annual stopping survey at the same intersection for nine straight years in the 1970s and '80s, finding a creeping decline. In his culminating 1997 masterwork, "Stop Sign Compliance: A Final Look," Trinkaus revisits his old intersection and finds that the percentage of people making a full stop had dropped from 37 percent  in 1979 to a mere 3 percent.

Why did this happen? There are several ways to read the data (and they are not necessarily mutually exclusive). On the one hand, traffic is a social environment, and authors like Robert Putnam in Bowling Alone, or Jean Twenge in Generation Me, have argued that stop sign scofflawism is one minor indicator, among many, of a larger societal shift: a decline of civility and reciprocity, a lesser willingness to follow social rules. The argument is that a society marked by increased self-regard (and hence less regard for others), has neither the inclination nor the situational awareness required to accommodate others, whether by signaling one's intentions, stopping for pedestrians in a crosswalk, or heeding the familiar red octagon. On the other hand, traffic engineers have long known that excessive signage declines in effectiveness. This points to something of a Catch-22. Residents of a neighborhood may complain about drivers speeding down their street and petition the city to install stop signs. But stop signs are not a safety device as such, nor a traffic-calming device: They exist to assign right of way. Faced with more stop signs, some   studies have shown, drivers may actually drive faster to make up time lost for stopping at (or really, slowing through) the intersection; the more signs installed, the lower the compliance.

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