Transportation is today’s topic.

First, a fantastic set of facts and figures on just how much space cars actually take up in cities.

According to the FHWA’s Highway Statistics report, large U.S. cities average 4.7 road-miles per 1,000 residents, or 25 road-feet per capita. Assuming 50-foot average road width, this is 1,240 square feet of road area per capita, or about 1,500 per motor vehicle. In addition, there are typically 2-6 off-street parking spaces per vehicle. These parking spaces, including their driveways, require, on average, about 300 square feet, or 600 to 2,400 square feet total…

As a result, in automobile-dependent communities with road and parking supply sufficient to keep traffic congestion to the level typical in U.S. cities, plus parking spaces at most destinations, a city must devote between 2,000 and 4,000 square feet (200-400 square meters) of land to roads and off-street parking per automobile. This exceeds the amount of land devoted to housing per capita for moderate to high development densities (i.e., more than 10 residents per acre, which means less than about 4,000 square feet per capita), and is far more land than most urban neighborhoods devote to public parks. This illustrates the problems that growing cities face if they try to develop automobile-oriented transport systems where most residents own a private car: they will need to devote more land to roads and parking than to housing.

Second, an interview with a Swede:

If we can create a system where people are safe, why shouldn’t we? Why should we put the whole responsibility on the individual road user, when we know they will talk on their phones, they will do lots of things that we might not be happy about? So let’s try to build a more human-friendly system instead. And we have the knowledge to do that.

But to do that we need to have those who build this to actually accept this philosophy. Even in our country context, it still has been a struggle to get our road engineers to understand that they are responsible, it starts with them. Then the individual road user also has a responsibility. But if something goes wrong it goes back to the designer of the system.

There’s a little bit of engineer-bashing there. We engineers are great at solving the problems that are put in front of us. We aren’t always great at framing the problem in new and better ways – for example, an objective of safe streets for all users and not just maximum flow rate of cars. But if you frame the problem in that new and better way and give it to the engineers, we will solve it for you.

Speaking of engineer bashing:

“If there was honest predicting, some percentage of them would under-predict traffic,” he said. “There would be a bell curve. Instead… what we have is these projections that are always immensely above what the actual traffic is.”

There is ample incentive for these firms to inflate numbers. Firms that predict high levels of traffic attract investment dollars and regulatory approvals, which lead to construction projects, and the same firms often end up directly cashing in.

The article is about some anecdotal cases where future traffic was overestimated, toll road companies went bankrupt, and taxpayers were left paying at least part of the bill. This is unfortunate, but it is a pretty serious charge to accuse an engineer of purposely enriching private parties at the expense of the public. (Full disclosure: I have professional ties to organizations mentioned in this article, although I don’t have direct involvement or knowledge of any projects mentioned.) I think the correct conclusion here is that it is time for some of the tools and assumptions and methods used in transportation engineering and planning in the United States to be seriously reexamined and brought up to date.