Research shows photo radar makes roads safer

There’s been a lot of discussion about the utility of photo radar – more properly known as automated enforcement – on Edmonton streets. While drivers everywhere have opinions about the efficacy of this traffic safety tool there’s no question that using it helps decrease motor vehicle collisions, thereby reducing injuries, fatalities and property damage.

While this contention is well understood among international experts who study traffic safety, the proof, as always, is in the research. For example, in 2013 my colleagues and I co-authored a paper titled City-Wide Safety Analysis of Mobile Speed Enforcement that focused specifically on the City of Edmonton’s automated enforcement program from 2005-2009. We wanted to examine the relationships between the occurrence of severe collisions and the number of hours of automated enforcement as well as issued tickets based on violations of speed limits. We discovered an inverse relationship: as the hours that automated enforcement was active on Edmonton roadways increased, and the number of issued tickets increased, the number of severe collisions decreased. Incidentally this research replicated a previous study published in 2010, with exactly the same results.

In 2014, we also published an evaluation of the effect of automated mobile speed enforcement on urban arterial roads. We wanted to study the relationship between the use of automated enforcement on arterial roads and the change in the frequency of collisions. Our findings were consistent with previous research, indicating significant reductions in all collision severities and types, with 20.1 percent of severe collisions reduced in known photo radar locations. Perhaps the most interesting finding of this study was what’s known as a spillover effect – when people know that photo radar is operating on one side of an arterial road they reduce speed, and therefore collisions, on the opposite side of the road as well, where automated enforcement is not in operation.

While I love my work as a traffic safety professor and analyst, I always find it disconcerting to have to convince people of something that those of us who study such statistics for a living find so obvious, especially when lives are at stake. There is a fact, deeply rooted in enforcement theory, that over time the presence of automated enforcement saves lives. As people get photo radar tickets in the mail and learn about automated enforcement, their behaviour changes behind the wheel, they slow down and collisions are reduced. For this reason automated enforcement is shown to be a useful supplement to police on the streets enforcing speed limits.

I understand and respect the public debate about automated enforcement, as citizens have every right to hold their governments to account on all public policy. I can only hope that those opposed to the practice and who remain unconvinced by academic research will acknowledge as much, and perhaps examine the reasons underlying their opinions in the absence of these facts.