Thursday, July 25, 2013

We don't build transit just to reduce congestion

In my last post, I talked about how expanding highway capacity doesn't reduce congestion. The primary study I cited mentioned, in addition to this, that building transit doesn't reduce congestion either.

This is interesting because congestion reduction is one of the primary reasons given for expending transit when presented at the ballot. But if it doesn't actually reduce congestion, why do we even build transit?

The reason for that is simply because there are other, better reasons for building transit than reducing congestion. That is, in fact, a very car-centric reason for doing it, when by its very nature transit provides an alternative to cars. The mindset around transit needs not to be "this will benefit me because other people will use it" but "this will benefit me because I will use it."

A good transit system provides a way out of congestion, rather than a means of reducing it. The main pitch for transit needs to be this: It increases mobility. And increasing mobility is the best reason for supporting transit.

Monday, July 15, 2013

The Fundamental Law of Highway Congestion

The first topic I'd like to address on the blog is congestion. This is something we're quite familiar with in the Seattle area. Not a day goes by without a traffic backup somewhere. We are, after all, a city of chokepoints. There are only two north-south highways leading into downtown Seattle, I-5 and highway 99. Likewise, there are only two east-west highways leading in as well: state route 520 and I-90, both of which have bridges to cross Lake Washington.

Common sense dictates that if you don't have enough lanes of traffic to handle the number of vehicles passing through, all you need to do is increase the number of lanes of traffic. It's true that this does increase your capacity. But does it reduce congestion?

A 2009 study on the subject suggests that it doesn't, in a paper by researchers Gilles Duranton and Matthew A. Turner. They cite something called the Fundamental Law of Highway Congestion first suggested by Anthony Downs in 1962. Downs himself said the following (cited from this source):

[E]xpansion of road capacity – no matter how large, within the limits of feasibility –
cannot fully eliminate periods of crawling along on expressways at frustratingly low speeds.

Basically, there is only a certain amount of congestion that people are willing to tolerate. Where alternative modes of transportation exist - buses, rail, bicycle paths, and so forth - people will use those modes of transportation to avoid congestion. But the latent demand is still there. When road capacity is expanded, that latent demand fills up the new capacity rather quickly.

The study offers only one solution for congestion that is proven to be effective, and if you're a driver, you're not going to like it: congestion tolling. By charging a higher toll on highways based on when the most demand is there, people naturally find alternatives and congestion drops.

It's also worth noting that the first paper cited finds no relationship between the increase in the availability of public transportation and reducing congestion. This is interesting because reducing congestion is often used as a justification for creating transit. This all goes back to the fundamental law: if people start using transit and leave their cars at home, the latent demand for highway lanes will manifest itself and the congestion will keep at the same level it was at before. Ultimately, you are moving more people with transit than you are without. There are better reasons for building transit than claiming it will reduce congestion - that is probably the least important reason, even if it's true.

Here's a couple other articles that cite this study, for your reading pleasure:


The Atlantic

I'll revisit the topic of congestion, congestion pricing and the fundamental law in the near future. I'm hoping to go into more detail and look at a few case studies. In the meantime, the next big topic I will begin to cover will be where the funds for transit systems (buses in particular) are coming from.

Wednesday, July 10, 2013

A Question to Ask Ourselves

My first series of posts is going to involve an examination of freeway capacity. Right now I'm looking for good sources on the subject that I can cite.

Until then, here's something to ponder. I overheard somebody the other talking about voting against every transit measure, and then said "I don't want buses. I want roads!"

So, here's the question to ask ourselves: Where do you want to go in a car that you cannot currently go because there's not enough roads?

After thinking about that, change the question a bit: Where do you want to go on transit that you cannot currently go because there's not enough transit?

You may find the answers to these two questions are very different from each other. I can't think of anyplace I can't go in a car for the first question. But I can think of a lot of places for question number two.

Monday, July 8, 2013

Why Transit?

When I lived in my home town of Olympia, I drove to get most places. The only times I didn't drive were when traveling short distances. I prided myself on having found tricks to get around traffic when driving home from work.

Then I moved to Seattle, where I was working downtown. I knew there was no way I could afford to drive to work and pay for parking on an intern's salary, so I started taking the bus to save money. Before long I was no longer an intern, but I didn't stop using the bus. I was still saving money, and I realized there were other benefits to taking transit as well.

About 7 years after my arrival in Seattle, I'm as big a transit supporter as they come. I started this blog because I want to help people understand the benefits of using transit, and why we should support its expansion.

From my perspective, there are two primary reasons we should support transit.

First, because it is an effective means of moving a large number of people from place to place, particularly when at least one of those places is densely populated, like downtown Seattle - the largest job center in the state of Washington.

Second, because I believe that transit can improve peoples' lives. Saving money is just the beginning: there are other reasons, such as reduced stress, better health, and more liveable, human-scaled neighborhoods, which tend to arise from areas that are well-supported by transit.

All that being said, I do own a car and think that cars are an appropriate means of transportation for many trips (like my errands I ran the other day, for which there was no way I could have accomplished them on the bus). But I also think that our transportation infrastructure has been way too focused on cars, and that we need to shift our focus more toward transit if we really are going to build a city that's ready for our future growth.

My goal for this blog is to make the case for more transit infrastructure, and hopefully change a few minds on the subject of transit.