A recent study from University of Toronto PhD student Sacha Kapoor and Arvind Magesan evaluated the impact of installing pedestrian countdown timers at various intersections throughout Toronto over a four-year period. After much parsing of data, the study concluded that installing countdown signals resulted in a five-percent increase in crashes versus intersections without the special signals. But there are nuances to that conclusion:
"The data reveals starkly diﬀerent eﬀects for collisions involving pedestrians and those involving automobiles only. Although they reduce the number of pedestrians struck by automobiles, countdowns increased the number of collisions between automobiles. We show that countdowns cause fewer minor injuries among pedestrians for every pedestrian on the road and more rear ends among cars for every car on the road."Further, while the the countdown signals increase crashes overall, at the most dangerous intersections the installation of countdown signals reduced crashes and made the intersections safer.
Unfortunately, nuances don't fit nicely into a soundbite. If you scroll through headlines of recent stories covering this study, you'll see two themes emerge:
- Pedestrian countdown timers cause more crashes
- Pedestrian countdown timers safer for pedestrians, hurt drivers
Neither of these statements is false, but they also don't tell the whole story about the effects of the signals. More importantly, if you're a policymaker faced with a decision about whether or not to install countdown signals, they could easily lead you to the wrong conclusion.