Monday, November 2, 2015

Are you from LA? You must like traffic

Lately I have been traveling to different states on weekly basis due to my work and interviews with other companies as I wrap up my college education. The traveling made me realize that each state has its pros and cons. From the beautiful Disneyworld in Florida to the Rocky Mountains in Colorado one thing became evident as I made conversations with locals, California is known for high taxes and traffic. The latter grabbed my attention as I often come across projects that seek ways to mitigate issues related to traffic. Currently I work in Santa Monica and my commute is perhaps one of the worst highlights of my job. The distance is only 11 miles however it takes me around 50 min to 1 hour to get to work (that’s an average speed of 12-13 mph). In addition, I am sure anyone living in Los Angeles can relate to the occasional heavy traffic at 1am on a normal weekend. The issue is a little complex and it goes beyond planning and traffic engineering. So what’s going on?

As a kid, I often wondered why the state build more lanes on the freeway or make double decker freeways (see picture below) to mitigate the demand of cars. But after some classes in traffic management, and transportation engineering I understood the concept that building more lanes only causes more traffic. In recent years traffic engineers understood that you can’t build your way out of congestion because studies show that the road themselves are what cause more traffic.

The economist Matthew Turner of the University of Toronto and Gilles Duranton of the University of Pennsylvania took a closer look at this phenomenon. The concept they used is called “induced demand” which is the way economist think when a product is delivered (in this case the roads) makes the end user to want to use it even more. Although research has been made before it was not until recent years that people collected enough data to make a plausible conclusion. This shows that the development of new roads are ineffective because the irrationality of the population when it comes to trying to avoid traffic in a highly congested city.
What the economist decided to do was to compare the amount of new roads and highways built in different U.S. cities between 1980 and 2000, and the total number of miles driven in those cities over the same period.
“We found that there’s this perfect one-to-one relationship,” said Turner.
The studies showed that if road capacities increased by X amount then the amount of driving also increased by X amount. Although the results are rather shocking the data is consistent along the whole study.
"As you add roads to a city those roads get filled up. There are people waiting to use that capacity. The result on transit is almost exactly the opposite of that." Turner added.
It could be that traffic engineers are building the roads based on the need of the community and their predicted traffic model fits perfectly with current traffic but Turner and Duranton thinks that it is highly unlikely. Their argument is based on the fact that the modern interstate network are closely related to the original plan developed by the federal government in 1947 and it is hard to believe that the engineers at the time could predict traffic behavior half a century in the future.

The study also took a look at public transportation and the results were alike. More trains, buses, troll systems, etc. created more users but that didn’t seem to relieve the traffic problem. I always thought of fluid dynamics as a model for traffics. In fluid dynamics you expect that by replacing a smaller pipe with a bigger pipe the pressure of the flow will drop causing a better flow. However, this is not the case for traffic, when you replace current roads with wider roads the traffic remains the same. It makes me wonder, where are this new drivers coming from? Were they included in the previous system before the widening of the roads?

According to a it has to do with what new roads allow people to do: to be able to move around. If you enable the possibility of driving more, they will do it more, causing to have more people willing to move farther away from work and therefore being forced to drive into town. It also means that if the widening of the streets causes an easier drive then it is more likely that drivers will jump in the car more often. Additionally, if there is more incoming traffic, businesses tend to develop faster which create extra traffic. The author argues that as long as the road remain cheap and accessible, people tend to overuse roads.

Interestingly, the study also showed that the phenomenon seems to work in reverse too. That is, when lanes are closed, population expects traffic to become much more chaotic. But the data shows that nothing too terrible occurs, that traffic readjust itself and congestion remains relatively constant.

So is this a never ending circle? Can we actually reduce traffic?  Turner thinks that traffic congestion could be solved if the right policies are formed and enforced. According to Turner we use our roads system ineffective because we have a central authority setting the standards and prices for our public transportation. In other worlds we all obtain what we want: roads, and we get charged next to nothing. So is he suggesting a privatization of all roads? What Turner and Duranton suggest is what they call congestion pricing.

That means raising fees when the traffic demand is high and lower fees or make it free when traffic is low. In Los Angeles there are many freeways that already include this systems but it would be interesting to see whether or not it would have a drastic effect when applied to all roads across Los Angeles. The challenge with that is that voters don’t tend to pass these plans because it is hard to accept to pay for something that used to be free.
They also think that if congestion pricing is not doable, then cities should look into mitigating that traffic by surcharging parking fees in order to make the community more cognizant of parking.

“Because it’s free, people will misuse it and it will be full all the time,” said Duranton. Drivers searching for parking contribute significantly to road congestion. “There are some estimates that say in the central part of cities up to 30 percent of driving is people just cruising around for parking,” Duranton said.
It seems to me that their studies pose solutions that are targeted to increasing prices and start charging for the usage of roads. Whether it works or not, I would like to think that there is a better way to mitigate traffic. After all that’s the job of engineers, to find and crea
te solutions to problems in a way that does not affect current conditions and that it’s also maximize the resources available.
The question is whether a small fee will make a big impact and If that’s the only option that mitigates traffic.

Next time you are sitting in traffic, don’t judge “the jerk” in front of you who just cut you off but the current conditions of our transportation system.


  1. It is so discouraging to read that if we add more roads, traffic will only increase more. I am an LA local, and am well versed in the horrors of traffic in the LA and greater LA area. Often times, I plan my day and schedule for traveling around traffic hour, because I simply can not waste my life away sitting on the freeway. And it astonishes me that people do sit through it. If i had to commute every day from LA to Santa Monica or Orange County to LA, I would get up at 4am and drive and be at work early and leave at 2 or 3pm before the 4-7:30 traffic hour starts. It is a cluster of chaos that inhibits the freeways, and I chose to stay as far away from that as possible. How can we ever solve this though? The cost to completely re-do this system would be endless, and the privatization of roads, while effective when you do pay the money, would just make the cost of living in California even more expensive than it already is. This just really discourages me from even wanting to get a job in the city after college, because the hassle and stress of traffic would literally take years off of my life.

    1. Just like you, I commute to work from DTLA to Santa Monica and I often have to sit in traffic for more than hour even if the distance is less than 10 miles. The main problem has to do with the way our infrastructure was built and the dynamics of the people living in Los Angeles. Whether or not this is a solvable issue the county has been looking at this for a while. The latest and most emergent challenge is LAX. With the extension of the rail system, LAX will work on mitigating the traffic by providing what engineers call "bullet trains" to transport people from the rail system to their end terminal in LAX, along with the new management systems provided by the airlines. The project is expected to end 2025. This will (hopefully) make a dent in the way traffic operates around the area. I agree that adding tolls will increase of California even more, but everything comes with a price. Maybe we could test it in some areas and see how the population reacts to it.

  2. I am actually not surprised at all that more roads would lead to more traffic. People will just assume that more roads means less traffic, so that it is okay for them to go drive. During the 405 closures a few years back, I remember everyone saying that the traffic was going to be so terrible, so they needed to get out of town. Many people left town or just avoided driving so that they would not have to suffer through the traffic. Because so many people did this, there ended up being no traffic at all! It was great!
    As far as paying higher fares during heavy traffic hours, I think that is terrible. Sometimes you just have to drive during a certain time. Higher fares would basically make it a double punishment because you are already being forced to sit in the bad traffic. I really hope someone comes up with a better solution.

  3. I completely understand your point about how increased capacity encourages more persons to drive on that road. I think that this should not be the mentality however. I think that the real problem lies with the number of people we deem possible to squeeze into Los Angeles. Perhaps the construction of a better public transportation system will help to resolve this. I know by personal experience, attempting to take public transportation to the beach is a complete joke. First I took the train to a bus stop, then I rode a bus around the city until reaching its final destination an hour and 45 minutes later. In other words, I learned that it is completely unfeasible to take public transportation to the beach, so now I contribute to the traffic that lines up in front of the ocean. Moreover, why should roadways be free while public transportation is exceptionally expensive? The fuel it takes to travel 20 miles in a car is cheaper than the number of tickets it takes to get around on public transportation. Thus, I have every reason to take a car. Now, I agree that increasing the supply for cars on a road will only encourage more demand, yet at some point that increase in supply is necessary and helpful towards commerce. Think, if Los Angeles had no roadway; they would not be the city they are today. Those people going in and out of the city are fueling the economy in one way or another, so if Los Angeles was better at getting more people in and out of the city, then they could make even more money! So whether it be an expanded freeway or public transportation system, the increased flow of traffic will ultimately pay off.