Streets versed Roads: Why Engineers Should Not Design Them But People Should

Empowering communities, people and business


From Strong Towns:


Last Friday I was participating in the 5th Annual Mayor’s Bike Ride in Duluth following a week spent sharing the Strong Towns message on the Iron Range. The friendly woman riding next to me asked me what could be done to better educate engineers so they would start to build streets that were about more than simply about moving cars. My answer rejected the premise of the question: We should not be asking engineers to design streets.

A quick review for those of you that are new here (which might be up to half the audience — amazing). Roads and streets are two separate things. The function of a road is to connect productive places. You can think of a road as a refinement of the railroad — a road on rails — where people board in one place, depart in another and there is a high speed connection between the two.

In contrast, the function of a street is to serve as a platform for building wealth. On a street, we’re attempting to grow the complex ecosystem that produces community wealth. In these environments, people (outside of their automobile) are the indicator species of success. So, in short, with a street we’re trying to create environments where humans, and human interaction, flourish.

Engineers are well-suited to constructing roads. Road environments are quite simple and, thus, lend themselves well to things like design manuals and uniform guidelines. There are only so many variables and the relationship they have to each other is fairly straightforward. In the United States, we have tested, refined and codified an engineering approach to roads that is pretty amazing and, in terms of engineering, the envy of the world.

There are two primary variables for designing a road: design speed and projected traffic volume. From those two numbers, we can derive the number of lanes, lane width, shoulder width, the width of clear zones and the allowable horizontal and vertical curvature. From those factors, we can specify all the pavement markings and signage that are necessary. We can then monitor things like the Level of Service, the 85th percentile speed and traffic counts to optimize how the road functions over time. Engineers are really good at this.

Engineers are not good at building streets nor, I would argue, can the typical engineer readily become good at it. Streets that produce wealth for a community are complex environments. They do not lend themselves well to rote standards or even design guidelines. There are numerous variables at play that interact with each other, forming feedback loops and changing in ways that are impossible to predict.


Source and full article:


Both roads and streets are needed (as is heavy and light rail) in any well-functioning city. It is how each are spatially distributed (and where Auckland fails miserably) that becomes the main problem for reasons mentioned above (with the humble engineer).


Even in Cities Skylines you work out pretty quickly between the definition of a road and street and what purpose each has with the surrounding physical and human environments.


From an earlier Transform Manukau series post in regards to housing:

#TransformManukau – Housing. Part 12 of the Manukau City Centre – The Transform Series


One also has to remember urban renewal in an existing residential area is more than sticking up some terraced housing and apartments and going here is your new home. There is the wider environment including the physical streetscape and the communities themselves.

Building wide roads that basically become traffic sewers is the fastest way of isolating the community of interacting with each other. Narrow low-speed streets where the people are put as priority over the car extend the “front yard” of a residential dwelling and can act as social points for the residents. The narrow low-speed streets becoming those extended front yards would also complement existing and new parks that act as green lungs to the intensified area.



This is in comparison to this which is 60km/h and not very people friendly:


That said you can try to humanise it as seen here by taking out the car parks and adding trees:

Road with trees
Road with trees and bus lanes




So indeed allowing the people to design and oversee streets (and even roads) would be one good step in restoring the human element to our cities and suburbs!