Last week, the Dallas Morning News published a front-page Sunday story that was deeply flawed. The online headline: “Red-Light Traffic Cameras Reduced Crashes, and Now They’re Gone. What’s Next for Dallas?” The story uncritically quoted city officials claiming that red light cameras made Dallas safer, before the city was forced by state law to remove them, in June.
DMN editors should have had the same thought I did when I read the story. Is it true? If they had googled “Are red light cameras effective,” like I did, they would have found on the first page of results a 2018 Star-Telegram story headlined “Intersections With Red Light Cameras ‘Likely to Be Among Most Dangerous,’ Study Says.” The study was conducted by some folks from Case Western who used data from large Texas cities, including Dallas. The lede of the Star-T story:
Red light cameras don’t cut down on accidents or make intersections safer, a new study shows. True, fewer motorists may blow through red lights, cutting down on T-bone type accidents. But the trade-off is that there are more rear-end collisions as drivers slam on their brakes to avoid going into the intersection and are hit by vehicles from behind.
So the first thing is, the editors at the DMN need to use Google. The headline in the paper should have read “City Officials Miss the Revenue Generated by Red Light Cameras. But Did They Actually Work?” I can’t explain what’s going on at the paper. Even with fewer people in the newsroom, they ought to be able to handle this sort of thing. As for whether red light cameras work, I do think I can explain that one.
The simplest way to think about red light cameras is that a bias is cooked into the process from the start. When Dallas picked intersections in which to install the cameras, someone asked, “Where are our most dangerous intersections? Give me the crash data from the past year.” There’s generally a good — but fleeting — reason that an intersection would rise to the top of such a list of dangerous intersections. It might be construction, either at that intersection or somewhere nearby, possibly causing cars to detour to that intersection. Even if a red light camera hadn’t been installed at the intersection in question, crashes would have decreased. When they do, though, transportation folks say, “Aha! The cameras worked!” The city rakes in millions of dollars in tickets, and everyone is happy.
Not so fast.
The folks behind the Case Western study I mentioned above — Justin Gallagher and Paul J. Fisher — looked at data not before and after red light camera installation but before and after removal. Their study has been updated since 2018 and has been accepted for publication in the American Economic Journal: Economic Policy. They used Dallas data as a control and made their conclusions about how red light cameras worked (or didn’t) in Houston. Here’s what Fisher told me via email:
Our estimations show that Houston’s red light camera program likely led to no change in, or slightly more, accidents driven by large increases in rear-end accidents and (likely smaller) reduction in angle and other red light running caused accidents. When the costs of operating red light cameras is included, we are confident they made Houston drivers worse off. Given the similarities between the programs in Dallas and Houston, I believe that the red light cameras in Dallas are no better and unlikely to be good policy.
I asked Fisher what he thought about Dallas transportation officials claiming that red light cameras made the city safer. His response:
I believe that they are wrong and were likely misled by outdated/flawed research presented by misinformed activists and camera lobbyists. Broadly, I view red light cameras as part of a trend to use criminal justice and public safety as an excuse to raise government revenue without raising taxes and/or to line private pockets by preying on those accused of crimes.
Again, all I did was google a basic question, find a research paper, and email an academic whose address was on said paper. Maybe Fisher is wrong about his conclusions (doubt it). But I don’t see how you write a story about red light cameras in Dallas without contacting either him or his colleague Justin Gallagher.
Let’s be safe out there. And critical of what our city officials say. (P.S.: Last week I emailed and texted Michael Rogers, the director of the city’s transportation department, to ask him about this issue. I’ve yet to get a response. If I do, I’ll update this post. And Fisher tells me that they are watching what happens in Dallas after camera removals, and when they have enough data, they’ll update their study.)
