Thinking about returns on investment

When do Cars Stop Helping a City?

Both Canadians and Americans are steeped in car culture. We as a people, dramatically overvalue the auto-mobile, especially in our biggest cities. This has lead some to declare there is a war on cars. If this were the case it would incredibly stupid, and after all who can argue with the fact that good automobile infrastructure is an economic engine ( …. engine…engine). The trouble is that all of the examples I gave show roads that connect between cities. They represent a cheap, flexible, solution to create a connected network of cities. That does not mean that cars are always a great option; in fact, in many contexts, they can cause more harm than good.

The When and Why for an Auto-Centric Solution

As I referenced in the hyper-links above, I think it is undeniable that automotive infrastructure can be a great economic driver. I think the merits of cars are easy to understand:

Roads are fairly cheap, and extremely flexible.

Cars offer freedom. You can go where you want when you want.

The above two points make roads viable in areas where other forms of transit are bound to fail.

This is why roads are fantastic at connecting cities, towns, and rural communities. They do not require super high usage, and there are no ongoing costs beyond some minor maintenance (in comparison to a train or bus network). This makes roads the only solution in many places.

Even in areas where mass public transit can be successful, the freedom of a car is something that no other mode of transit can match. This may not be important within a city, but it certainly is if one wants to leave the city to go to a more remote destination (hiking, camping, fishing etc.).

The problem is that the merits of highways, roads, and cars as a whole are very sensitive to population density. As a result, the very same features that make automotive infrastructure attractive in one setting, can make them destructive in another.

Different Settings Means Different Solutions

When considering transit infrastructure, there are many complex considerations. As with any field of engineering, it proves useful to try to focus in on the most important issues at hand. This is very dependent on the situation at hand, but a great, and pertinent, example is constructing a road network.

Considerations for a Road Network

Travel time

Speed of vehicles

Pedestrian Safety

Width of Road

Parking

Pollution

Environmental impact

Noise

Capital/Maintenance costs

Width of sidewalks

Incorporate non-automotive transport

Connectivity

Fuel/Food stops



I have highlighted issues which are primarily urban in blue and those which are primarily rural in green. This means that the considerations for a rural road would focus on the following

Considerations for a Rural Road Network

Minimize Travel time

Maximize road speeds

Minimize lifetime costs of road

Connect well with population centres (towns etc.)

Ensure sufficient fuel infrastructure is in place

Most Canadians’ (and certainly Calgarians’) thought process when considering transit infrastructure is very rural in nature. In my experience this thinking is independent of where someone lives. In reality though, if I want to build roads in a city I need to consider a lot more

Considerations for an Urban Road Network

Prevent road from being too wide – takes up valuable land

Ensure speeds are not too high so as to harm pedestrians

Consider noise and emission pollution for roads in close proximity to people

Cannot cannibalize the city

Safe for cyclists, mopeds, and public transit

We can see immediately that all of these considerations become more and more important with increasing population density. The rural designer was very justified in their choice to ignore these considerations. As we think about denser and denser cities, these become more important.

I want to focus on the bolded point though, because this is a real philosophical shift. When you are designing transit for a city, you are trying to do two things. One is to make it easy to move about within the city, and the other is to let people travel in and out of your city. Both are important, however it is important not to lose sight of what you are servicing: the city itself. You should want your city to be somewhere to drive to not a place to drive through.

This is important, because without this thought in mind the solutions you will come up with will involve wide roads, without considering the limited the growth of your city.

Why the War on Cars?

I feel this term has as much legitimacy as the war on Christmas, however it is still worth addressing the question: why do so many people seem to push against cars? The answer is two-fold. The first factor is geometry; the second factor is that they are putting a greater emphasis and the city you drive to.

To understand this you have to believe that the best cities are dense cities, if you do then you realize that if we built roads like a rural thinker our city could never achieve that density. This idea is spelled out beautifully in the book The High Cost of Free Parking it goes something like this. If you have free parking, things get less dense. Less of the population chooses to walk, and more use cars, which only further increases the demand for free parking. Things are spread out enough until your entire city is car dependent. You city is driven towards sprawl instead of density.

This is the crux of the problem, if you do not fight automotive infrastructure you cannibalize the city. This is driven, almost entirely, by the size of a car. They are extremely space inefficient, and in a dense city, spatial efficiency reigns supreme.

Public transit, bicycles, and walking are free of these issues. The minimum spatial consumption is the size of the person themselves. This is kind of the fundamental limit. Cars can still fit into the story, we all still want some freedom, some people will want to go camping, and there are certain times a car provides an indispensable service. All that said we need to view cars as a complimentary piece of our transit network if we are going to see Canadian cities grow and prosper. The truth is that people are not fighting a war against cars, they are fighting for transit, for walkable streets, and for a vibrant city that they can call home.

When to Switch From Cars to Public Transit

So all I have really done in this article is argued that in dense cities cars should be seen as an auxiliary component of a broader transit network, while in smaller, less dense environments cars provide an excellent solution. I have not even tried to broach the subject of what to do in between.

This is a tough question, and its not one I can answer, but I think you can see the different factors you have to consider when thinking about these things, especially if you are planning for growth.

Transit infrastructure is expensive and we should think about it as an investment. The real question is what is the return on that investment? At some point it can actively hurt your city, and there it is obviously not the right choice. The more difficult question is: When does building public transit represent a more effective use of taxpayer dollars than building a road network?

If you want to leave your own answer in the comments I would be interested in hearing your thoughts (or if you have a lot to say you could even write a letter to the editor).