Carbon Efficiency: Walkability and High Density

The chapters from The Carbon Efficient City, specifically on “Great Neighborhoods” remind me of a TED talk “The Walkable City”, delivered by Jeff Speck who is a city planner/urban designer, and the author of Walkable City: How Downtown Can Save America, One Step at a Time. He brought up an interesting point in suburban sprawl, city density and how it is related to energy consumption. He argued that by establishing new suburban areas to ease the crowdedness of inner cities, it actually and inevitably increases energy consumption.

The first reason is because when sprawls are developed, one of the main infrastructures, particularly the highways, will either have to be newly constructed or widened accordingly. However, the underlying problem is that new suburban areas may only provide new residential locations but not the residents’ workplaces and enough amenities; they still commute to the inner cities to work and get the things they need.

Then the second reason becomes clearer. The consequence is that the automobile use increases; the convenience of having the new highways also means more personal vehicles. Commuters would have to spend more time in cars and rush through the traffic. Does suburban sprawl help in the reduction of energy use? Probably not.

Jeff went on and discussed how walkability and maintaining/increasing density could help reduce energy use which would lead to reduced carbon emissions. At the same time, it would pave the way for people to use other means of transport that are less energy dependant (walking and biking). I’d like to quote his statement that I found is thought-provoking; “we are a destructive species; if you love nature, the best thing you can do is stay the heck away from it and move to a city; the denser the better”. This may sound contradictory, but referring to him, the carbon mapping shows that denser cities perform better when measuring carbon per household.

Designing a walkable city has a lot of benefits. Driving less means more productivity as a result of less amount of time spent on roads. People would be able to recreate more in a variety of ways in the walkable city. They can exercise by walking and biking while getting to the destinations—possibly decreased cases of obesity and respiratory diseases due to fewer exhausts. Car crashes would also decrease.

By looking at Liz Dunn’s advocate for the concept of “urban grain” that engages the rethinking of strategic block-scapes. To optimize the use of the existing buildings and bring up the unique character of a neighborhood is promising in order to avoid total demolition.

In addition to the unban grain framework, one way to manage density is to consider street grid. The grid and block sizing plays an important role in determining if a city is walkable and socially, economically vibrant. “Street Area Calculator” is a way to measure. What’s interesting is that though having more streets (in response to having a lot of blocks) means more areas being devoted to more car use, having smaller city blocks actually allows for more building and street frontage. With the help from pedestrian-friendly sidewalks, the street frontage creates different commercial activities and therefore, more safety, as opposed to larger blocks that there normally are buildings with blank walls facing the road.

When speaking of density in cities, to some people (and including me), it may connote to something that is tight, unhealthy and unsafe. I used to picture all those descriptions myself. However, the fields of landscape architecture and urban design and planning has gotten me thinking that density is not always unpleasant especially when there are cities that urban density in fact has benefits. The important thing is that we can make it work socially and economically.


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