At the National Building Museum, Patrick Condon, ASLA, a professor of landscape architecture at the University of British Columbia, gave a run-through of his new book, "Seven Rules for Sustainable Communities," which argues that bringing streetcars back is the smartest thing cities can do become more sustainable. For older cities, unearthing "barely submerged" streetcar networks may be easy, but relatively new communities can also invest in laying streetcar infrastructure at a cost significantly less than subways or light rail. To get to a 90 percent cut in greenhouse gas emissions (GHGs), transportation emissions must be zero. Making communities walkable and bikeable are crucial, and electric vehicles will also help, but 40-50 percent of the U.S. urban fabric is already set-up for the "Streetcar City" so it's just a matter of investing again in an old model that worked well.

Rule 1) Restore the Streetcar City

How can we make the change to a low-carbon society in the most cost-effective way? Whay is remotely conceivable as a new paradigm?, asked Condon. Looking at different options, Condon sees streetcars as the most feasible path given these systems work well with the single-family homes that dominate the American and Canadian landscape. Streetcars can easily be added back into communities with corridors and many suburbs can also be retrofitted to include them. "It's only in the 3rd of 4th ring of suburbs that you can problems with cul-de-sacs" and other built-in inefficiences that make the car so hard to unseat. However, Condon said lots of "friends in transportation planning don't get this idea." Also, many New Urbanists also haven't taken to it.

Land use changes can help reduce 50 percent of greenhouse gas emissions (GHGs). When you add in greener buildings and transportation networks, communities can get to 80 percent reductions, says Condon. The streetcar city is so central to sustainability because it would be the most efficient way to leverage land use and transportation changes together to reduce GHGs. In addition, every community with a population over 5,000 in the U.S. once had streetcars so they worked once. In the modern era, the Siemens Combino tram is the cleanest out of all transportation options Condon listed, with 8.3 tons of GHG emissions per passenger. Trolleybuses, with 10.3 GHG per passenger, also work OK, although streetcars are the more efficient option over the long-term because they carry more passengers. Both options are far more clean than other options like light rail, diesel buses, or cars. (Condon left our clean, natural gas buses or hybrids along with electric vehicles in his comparison).

In addition, bringing back streetcars would support density. In Vancouver, the streetcar was added first, then developers subdivided properties into lots. More than 80 years later, dense, mixed-use development was filled in, realizing the developers' initial vision of density.

Unfortunately, for many cities that had the streetcar arterials in place, "the forces of auto sprawl" took over the inter-urban system. As a result, post-streetcar, cities and communities have moved away from dense living in townhouses to one-story bungalows that don't make efficient use of space. Without the streetcars, cities lost mobility. Condon pointed to Los Angeles, where "mobility has been degraded with the removal of the streetcar."

Condon also outlined North America's "Friday the 13th demographics," arguing that the country is rapidly aging. Instead of gangs hanging out in inner-cities, it will be the elderly, and "we don't want these people driving around." At a cost of $20-25 million per kilometer, streetcars can be added to many communities providing low-cost access for rapidly aging baby-boomers. Hopefully, those Siemens combinos will be less screechy, slow, and packed than San Francisco's remaining streetcar lines.

Rule 2) Design an Interconnected Street System

The U.S. continues to create hub and spoke transit systems even though jobs "are no longer in the center of those hubs." Jobs need to be located close to home. To encourage this change, "the left-over ideas of the 1960?s" focused on the car need to be thrown out. In sprawl conditions, "there are no alternative networks, and the main intersections are highly loaded." This enables the growth of big box stores, intersections that pedestrians can't cross, increased traffic through those intersections, and a higher number of traffic fatalities. In contrast, interconnected streets can provide many alternative routes to reduce congestion. Condon argues cities "need to get in love with corridors" that can enable access to side streets and facilitate the growth of density.

Rule 3) Locate Commercial Services, Frequent Transit, and Schools Within a Five Minute Walk

Here, Condon said, there is consensus among many smart growth and New Urbanists planner and landscape architects. However, many communities that are car-centric still have a hard time achieving walkable zones, particularly for schools.

Rule 4) Locate Good Jobs Close to Affordable Housing 

Sources of jobs should be close to residential areas. "The streetcar city allows for many jobs closer to corridors." Dense, mixed-use developments in inter-connected street networks enable this kind of smart growth. Far-out, isolated industrial parks covering 80-100 acres aren't the way to go. Instead, one-acre sites should be a model. Also, communities can "build in jobs" in strip commercial areas by building up, adding in new uses.

Rule 5) Provide a Diversity of Housing Types

For slower transit like streetcars to make sense (they average around 12mph), affordable housing must be more evenly distributed in regions. "The housing stock in many regions is set up for the Cleevers. However, demographics are changing." There should be many different housing types on the same street close together. If done correctly, diversity doesn't need to look dense, argued Condon. 

For example, Vancouver has allowed the use of "hidden secondary suites," which are often called "illegal suites," in single-family homes that can be rented out. "Laneway houses" are also now acceptable for renting out. Condon says Vancouver should be viewed as a model for how to re-configure single-family homes for multiple-unit dwellings.  In another model development in Vancouver, Condon pointed to a set of stacked townhouses that sit above commerical space, which then sits on top of street-level retail and an underground "big box" store.

6) Create a Linked System of Natural Green Spaces

Saying he would be remiss to add this given he's a landscape architect, Condon pointed to linked natural parks as a good fit with streetcar networks. "Preserved nature provides a natural interface for streetcars." For example, Frederick Law Olmsted's Emerald Necklace system in Boston, which "is better, bolder than Central Park," is not only an ecological solution for stormwater management, but a great example of how to use "dead space" to complement a streetcar system.

In addition, the necklace system presents a model for how to "be aggressive with nature." Condon called on landscape architects to "not just put fences around the remaining remnants of natural history in a city," but "work with nature" to create a new, vibrant environment within cities.

7) Invest in Lighter, Greener, Cheaper, and Smarter Infrastructure

Green infrastructure, which involves using man-made systems to mimic natural functions, is "smarter infrastructure." Condon argued that communities should be "preserving the natural functions of the landscape" as much as possible. "Water doesn't runoff natural landscapes."

The rule for green infrastructure systems should be to reduce and capture one inch of rainfall per day. As an example, Condon pointed to Pringle Creek, which he said has one of the "most advanced green infrastructure systems available at the urban scale." There are no stormwater drainage pipes or curbs. During three 100-year storm events, there also wasn't any flooding.

Check out Condon's book.

Image credit: Patrick Condon / Island Press