O RLY? Removing highways makes city traffic move easier
One solution to the upcoming increase in traffic jams, says the Texas Transportation Institute, is to increase the carrying capacity of roads in cities. But two writers at the Infrastructuralist think there is a good case to be made for demolishing in-city highways. The benefits don't stop at getting rid of ugly concrete snakes from city centers. Fewer highways can also lead to better - yes, better - traffic patterns.
Jebediah Reed and Yonah Freemark cite four examples - Harbor Drive in Portland, Oregon; the Central Freeway and the Embarcadero Freeway in San Francisco, California (pictured); and the Cheonggyecheon Highway in Seoul, South Korea - where big roads were taken down. In these cities, not only did the areas where the highways used to be prosper, but traffic flow actually increased. Reed and Freemark cite the Braess Paradox and each driver thinking of ways to optimize their route as key players in the "add more roads, get more traffic" conundrum. When the city highways in these four examples were torn down, people naturally found other ways to get around, dispersing the traffic flow. Reed and Freemark don't advocate tearing down every highway in every city; they just want to shove the idea that more roads is always better out the door. Well done.
[Source: Infrastructuralist via Treehugger]
Photo by meglet127. Licensed under Creative Commons license 2.0.
Reader Comments (Page 1 of 1)
Matt 2:03PM (7/08/2009)
Adding roads is like throwing money at a problem: it might work, but most of the time it doesn't unless you have good planning. City planning is the real key to alleviating traffic problems, but bureaucrats rarely have the longevity or knowledge to implement a plan. Unfortunately, they are the ones in control of tax money, not the civil engineers and architects. Many small roads with timed traffic signals >> one big road with no signals.
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mike 2:14PM (7/08/2009)
Rather than tear down all that expensive infrastructure... they should convert it to light rail.
The whole "build it and even more will come" problem of highways is pretty interesting stuff though. I recall seeing an awesome pbs documentary on it a while back.
- mike
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BlackbirdHighway 2:25PM (7/08/2009)
Ok, I'll agree with Braess's Paradox being at work here, but I also wonder if another effect partially explains it.
Braess's Paradox basically says that everyone will choose the "best" path at a personal level, even though if a few of them choose a longer path, the best path would be less congested and the total commute time for all concerned would be less. Simply stated, none of the drivers are willing to "take one for the team", so everybody suffers.
But I believe that another effect behind the observed results is the spreading out of traffic. If 8000 cars are spread out over 20 miles of road instead of 10 miles of road, then congestion will be less and average speed much greater. That's what happens when the direct, 10 mile road is removed. Still, even though speeds might be higher, the fact that the cars have to travel a longer distance could very well mean that both travel time and fuel consumed are greater.
Don't get me wrong, I'm not in favor of building more roads in the city, just think the issue could use more study to understand what's really going on. Another big cause of congestion is having too many entrance/exits too close together. Other alternatives such as promoting public transportation, and encouraging drivers to take alternate routes by imposing rush hour fees or HOV restrictions need to be considered as well. We need a holistic approach to traffic management.
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locoyocal 2:30PM (7/08/2009)
Amen,
Texas government is holding us hostage.
There is a highway where I live with stop lights. Overpasses were already planned/funded for.
Instead, the Governmental folks have scrapped the plans and are trying to stuff a plan down our throats to accept a toll road that adds 6-12 more lanes.
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Jacob 4:03PM (7/08/2009)
We're in the process of widening a section of I75 down here in SW Florida from 4 lanes to 6. Some clever people wanted to jump from 4 to 10 lanes by tolling lanes 5-10 (even though two of the lanes are already paid for.)
TGNY 5:44PM (7/08/2009)
Check the book "Suburban Nation" for the supporting findings. Great book on planning.
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Christopera 8:04PM (7/08/2009)
It's well known that more roads actually creates more traffic. There are literally hundreds of urban planning articles that have shown this to be true.
It's too bad that the States decided to ignore dispersed travel methods and dense population formations and just built super highways around our cities and encouraged miles of sprawling suburban crap holes.
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Chris M 9:03PM (7/08/2009)
That's odd, some claim that our traffic problems are a result of cities being spread out in "suburban sprawl", which of course is the direct opposite of "dense population formations". I guess it really depends on what agenda is being promoted.
Chris M 9:10PM (7/08/2009)
Intersections can cause slowdowns in traffic, so sometimes removing roads can reduce the number of intersections, thus paradoxically improving traffic. Of course, that assumes the remaining roads are adequate to handle the traffic.
Freeways can divert traffic off of other roads, but they sometimes dump too much traffic onto too few exits, which can cause local traffic jams. Also, spurts of traffic from local traffic lights can trigger traffic jams and backups during peak traffic hours, that is why "metering lights" work, they smooth the flow of traffic and reduce "bunch-ups" that trigger jams.
So, whether or not removing a road can improve traffic flow is a big case of "It Depends".
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Rick 4:35PM (7/09/2009)
Sorry but the prospect of driving city roads with a light every block vs doing 75mph on the highway to drive the distance of 24 miles each way doesn't sound like a good idea and would easily triple the amount of time needed to get to work/home.
Besides, isn't a car stopped at a red light bad for emissions and the environment? This would effective double quadruple plus more the amount of cars stopping at street lights on a daily basis.
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axio.matik 2:16PM (8/21/2009)
Your comment has nothing to with this post. If you are consistently able to go 75 on the highway, then you aren't suffering from congestion, which is what this post is about. The point of this study is to compare travel times for commuters who routinely commute on a heavily congested freeway (let's say average speed during rush hour is 25 mph), versus what their commute time would be if the freeway didn't exist. Also, cars sitting still, stuck in traffic on the freeway isn't really any better enviromentally then sitting at a light.
Freeways seem to have the effect of funneling traffic towards themselves. People tend to take freeways not because it is the shortest distance, but the perception that it will be faster. This concentrates many more drivers onto a single road (the freeway), versus the distributed traffic that would occur if the freeway did not exist.
I've often thought that this was one of the major contributions to the terrible traffic on Los Angeles' freeways. It seems to me that there are just entirely too many of them. Every couple of miles you are dealing with traffic merging from one freeway to another, which always causes a major bottleneck that slows traffic for miles behind it.