

Jim Saska is a jerky cyclist, something he cheerfully cops to (he also admits that he's a dick when he's driving a car or walking, and explains the overall pattern with a reference to his New Jersey provenance). But he's also in possession of some compelling statistics that suggest that cyclists are, on average, less aggressive and safer than they were in previous years, that the vast majority of cyclists are very safe and cautious, and that drivers who view cycling as synonymous with unsafe behavior have fallen prey to a cognitive bias that isn't supported by empirical research.

The fact is, unlike me, most bicyclists are courteous, safe, law-abiding citizens who are quite willing and able to share the road. The Bicycle Coalition of Greater Philadelphia studied rider habits on some of Philly's busier streets, using some rough metrics to measure the assholishness of bikers: counting the number of times they rode on sidewalks or went the wrong way on one-way streets. The citywide averages in 2010 were 13 percent for sidewalks and 1 percent for one-way streets at 12 locations where cyclists were observed, decreasing from 24 percent and 3 percent in 2006. There is no reason to believe that Philly has particularly respectful bicyclists—we're not a city known for respectfulness, and our disdain for traffic laws is nationally renowned. Perhaps the simplest answer is also the right one: Cyclists are getting less aggressive.

A recent study by researchers at Rutgers and Virginia Tech supports that hypothesis. Data from nine major North American cities showed that, despite the total number of bike trips tripling between 1977 and 2009, fatalities per 10 million bike trips fell by 65 percent. While a number of factors contribute to lower accident rates, including increased helmet usage and more bike lanes, less aggressive bicyclists probably helped, too…

…[Y]our estimate of the number of asshole cyclists and the degree of their assholery is skewed by what behavioral economists like Daniel Kahneman call the affect heuristic, which is a fancy way of saying that people make judgments by consulting their emotions instead of logic.

The affect heuristic explains how our minds take a difficult question (one that would require rigorous logic to answer) and substitutes it for an easier one. When our emotions get involved, we jump to pre-existing conclusions instead of exerting the mental effort to think of a bespoke answer. The affect heuristic helps explain why birthers still exist even though Obama released his birth certificate—it's a powerful, negative emotional issue about which lots of people have already made up their minds. When it comes to cyclists, once some clown on two wheels almost kills himself with your car, you furiously decide that bicyclists are assholes, and that conclusion will be hard to shake regardless of countervailing facts, stats, or arguments.