By Matthew Owens March 19, 2013
As outlined in the recent article, "A radical plan," small sized, but higher density development could replace our current sprawling suburbs and thereby eliminate the need for cars and commuting for most people. Aside from enormous costs savings ($9,000 per year to own one car on average in America, according to AAA's latest report), health benefits, and time savings (500 hours a year for the commuter who spends an hour traveling each way to and from work), there would also be critical benefits to our planet's climate. In fact we would even stand a very good chance of avoiding 6 degrees Celsius warming by 2100 and the mass devastation that would ensue. But just what would these "mini-cities" look like?
Above right: the Horniman Museum in London, England uses a slanted green-roof to lower its cooling and heating bill and improve local water quality. Green roofs also add to the local ecosystem, and they can have a great visual impact! Flat rooftops can be made into usable garden refuges. Photo credit: secretlondon123, via Flickr.
In the previous article, I considered sizes about 1 mile in radius which would make most destinations fall within a 15 minute walk. Of course, electric scooters, bikes, and all other sorts of small light transport could make that transit time even faster. For example, a bike could double the average walking speed of about 4 miles per hour, and get you to your goal twice as fast. Plus, with everyone commuting on foot, bike, etc., there would almost certainly be covered sidewalks running throughout these cities to protect citizens from the elements (except maybe in balmy places like California). And in colder or harsher climates these covered walkways might even be slightly climate controlled in addition to providing a buffer against wind, rain, and snow.
As for the development density and average building height, there would be quite a diversity possible (see tables 1-4). For example, a mini-city that's only 30,000 people large could easily maintain a two-story height limit on all buildings. In fact, such a place could probably maintain a single level height limit! For higher density mini-cities, say with a population of 70,000, around 3 stories-tall would be the required average height of residential buildings. Or at the extreme, a locality could have very tall buildings, but only a few of them, with large open spaces in between, and still meet the criteria for being walkable.
Above (Click for larger view): Tables 1 through 4 show variations in average residential building height by mini-city population and average floor space (in square feet) per person; examined in all tables are populations ranging from 30,000 to 90,000 and then each table uses a different average floor space per person, ranging from 550 to 1,000 square feet per person.
Meanwhile, rooftop gardens, pools, vegetable plots, and other interesting uses of space could make the interior of these proposed mini-cities quite enjoyable too. And of course, being only 1 mile in radius would mean that getting out of the city and into the open country side would be a 5 to 10 minute walk for most people (assuming the residential areas are located on the edges and the commercial areas are located in the center).
Underlying all the assumptions above, I've been considering a residential area that constitutes of about 20 to 30% of the mini-city total land area. This is similar to other cities today. But as Tables 1 - 4 show, variations on this ratio would allow even more diversity in design and layout.
Is it time to make this a reality? There seem to be plenty of eager bikers, more and more in fact, and a growing awareness for consuming local foods - but as individual choices without a radical plan to enable large restructuring, these actions alone will not be sufficient to keep a 6 degree world at bay.