Removing highways - Solution or a disservice?

Today, an article was posted on the New York Times suggesting that in order to revive urban centers all over the United States, many cities are considering removing high-volume roads and highways from the city center.

When discussing the traffic impacts of such interventions, the narrative prevails that little impact on traffic levels is seen on neighboring roads at first glance. However, this does not necessarily mean that the planners are not causing a disservice within the network from a transportation point of view.

From an urban development point of view large highways have a very segregating effect. Physically, these become barriers of social engagement. Pedestrians are much less likely to cross highways than single-lane urban roads.

Socioeconomically, highways can depreciate the value of real estate in their vicinity, at the same time as the appreciate the value of sub-urban real estate because of the improvement in accessibility between sub-urban neighborhoods.

Accessibility is a term often used in transport and land-use planning, and is generally understood to mean approximately ’ease of reaching’. Accessibility is concerned with the opportunity that on individual or type of person at a given location possesses to take part in a particular activity or set of activities.

As the NYT article illustrates, there exists massive potential in urban redevelopment through the removal of these highways, encouraging walking, improving the green areas and start creating communities instead of offering them “a highway and go directly out of our community” This could however lead to clear consequences on the traffic.

The authors shrug this off by writing:

And the big fear of removing a highway — terrible traffic — hasn’t materialized.

Let’s be clear:

• From an urban development point of view (p.o.v.), the removal of highways has positive effects on the life of those living in close vicinity
• From a transport behavior p.o.v., it can be logical that “terrible traffic” will not materialise.
• People are very adaptable and if they have less choice, they still optimise their travel behavior, given the opportunities they are provided with, although the choices today may be worse than yesterday. From a transport planning standpoint, removing a highway can be quite significant. If news articles like this, or review articles suggest a narrative that claims it has no impact on traffic, or even that it “disappears”, such claims are, at best, misleading.

So where does the traffic go? Let’s consider an example.

Let’s consider neighborhoods A, B and C. They are linked with links 1-4. At nodes B and C we have large supermarkets, whereas node A is served by a cornershop. The planners suggest to remove highway 1 because residents in between A and B are severely affected by noise and the highway splits up a school neighborhood.

Prior to removing the highway, the planners measure the traffic on neighboring roads 2 and 3 which are much slower than the highway 1 because they lead you through smaller roads. These counts on road 2 and 3 see little change after the highway has been removed.

Those residents of neighborhood A who before the highway removal did their shopping at supermarket in B will, instead of traveling through narrow roads 2 and 3, either settle for the corner shop in A or travel further to C.

Ergo, while it is true that we may not measure an increase in traffic on neighboring roads 2 and 3, as suggested by this article or in some scientific findings, this does not exclude the idea that we have actually reduced the accessibility within the network and may lead to a disservice within the network. We should not ignore, or belittle that effect. However, the service provided by a park or other opportunity replacing the highway may be larger from an urban planning standpoint than the disservice in the reduction of accessibility from a transportation standpoint.

This small thought experiment highlights the necessity for urban planners, transport planners and infrastructure planners to work together. This can improve our cities.