Colin Fiske, Executive Director
Nobody likes sitting in traffic. Consequently, “congestion relief” is one of the most popular things a planner or politician can propose. After all, when you’re stuck in gridlock on a freeway, desperate to get moving, it seems like common sense that the people in charge should add more lanes to accommodate the traffic. But here’s the dirty little secret behind congestion relief projects: they don’t work.
Researchers have studied these projects for decades, and the evidence is overwhelming: when you add capacity to a road that is currently congested, more drivers will soon use that road, and within a few years it will end up just as congested as before. (The academic term for this phenomenon is “induced demand.”) Nevertheless, we keep trying this same failed approach year after year.
It may seem odd to even be addressing this topic on the North Coast, where there is no real traffic congestion to speak of. But even here, the idea of congestion relief is deeply ingrained in our plans and projects. Review any local government’s transportation policies, and you’ll find references to “level of service,” which is traffic engineering lingo for how much congestion they’ll allow on their streets and roads. In an attempt to address this issue, the Arcata Planning Commission recently voted (at CRTP’s urging) to “de-prioritize” congestion management in the city’s General Plan. But most of the actual projects contained in that plan still list congestion relief as their primary purpose!
While largely ignoring the fact that congestion can’t actually be relieved by adding capacity (whether that’s a new road, a turn lane, a traffic signal, or any number of other “improvements”), defenders of the status quo continue to perpetuate other myths in support of congestion relief projects. Here are a few of the more popular myths:
- “Congestion relief is good for air quality and/or the climate.” It’s true that individual (gas or diesel) cars produce fewer pollutants per mile when not stopped in traffic. But the fact that congestion relief projects lead to more driving means that the overall effect is a lot more emissions.
- “Congestion relief projects improve safety.” Sometimes people argue that a smoother flow of traffic reduces collisions, because stop-and-go traffic leads to a lot of fender-benders. But the fact is that few people are injured in collisions when cars are stuck in traffic, because they’re driving really slowly. Creating the conditions for them to drive fast is the actual safety threat.
- “If we don’t relieve congestion on this major artery, the traffic will divert to other neighborhood streets where we don’t want it.” Like the other myths, this one seems logical on the surface, but there is little evidence to support it. Research has shown that even actively removing lanes or whole streets usually does not result in significant traffic diversion. One possible explanation is that capacity limitations on nearby smaller streets make them just as slow as a bigger street clogged with traffic, so there’s no incentive for drivers to change their routes. Which means that any diversion that might occur can be reduced or eliminated by implementing more measures to slow traffic on the alternate routes.
Hopefully it’s clear by now that, while it may be annoying to wait a few extra seconds at an intersection, traffic congestion isn’t something we should be collectively worried about. In fact, where it exists, it can even have a positive impact by improving safety (slow cars are safe cars) and encouraging people to use healthier, lower-carbon modes of transportation. Let’s get congestion relief out of our local plans and start encouraging the only thing that will really make it more fun to commute: doing it without a car!