The Twentieth Century marked a dramatic shift in city building. Rather than developing urban areas that prioritized the safety and movement of people, civic leaders began planning cities around automobiles. The negative consequences of this transformation are to be seen everywhere. Traffic congestion, air pollution, and soaring obesity rates are all attributable to our almost ubiquitous reliance on automobiles as our primary means of transportation. To create Symbiotic Cities, transportation must be planned to support and be supported by higher densities. This can be achieved by establishing policies that promote the development of walkable and complete communities. It also requires investments in public transportation, pedestrian infrastructure, and renewable fuel technologies. 


In 2006, 25% of Canada’s greenhouse gas emissions were produced by the transportation sector. Urban passenger travel accounted for half of that total. [Source: Transport Canada, Active Transportation in the Canadian Context, 2006; http://www.tc.gc.ca/media/documents/programs/atge.pdf] Urban mobility in Europe accounts for only 8% of all GHG emissions, due to their greater reliance on public transportation systems, 40-50% of which now run on renewable energy sources. [Source: Towards Zero Carbon Mobility in Europe ] Decreasing our reliance on cars would have immediate benefits for air quality, and our personal health. It is estimated that if every Canada left their car at home one day per week, we would save 38.9 mega-tonnes of GHG emissions each year – that’s equivalent to taking 800,000 cars off the road. 

Decreasing automobile dependence makes both environmental and financial sense – for both cities and their citizens. Maintaining road infrastructure is a massive burden for cities. For example, in Canada, federal, provincial, and municipal governments collect nearly $16 billion in fuel taxes, license fees, and other motor vehicle payments from drivers annually. However, between 2010-2011, Canadian governments spent $29 billion to construct new roads and maintain existing automobile related infrastructure - which is far more than is spent on transit, rail, air, marine, and all other transportation modes combined. The remaining $13 billion worth of road infrastructure is subsidized by all Canadian taxpayers - many of whom are not motorists.

The negative externalities associated with automobile are estimated to cost Canadians an additional $27 billion per year. The externalities (accidents, air pollution, climate change, congestion) of automobile use in the European Union are estimated to total 373 billion € per year, roughly 3.0% of the combined GDP of the 28 member countries. Air pollution, climate change, losses from injury and death, and decreased productivity due to congestion, are just some of the less tangible, yet crucial consequences of auto-dependence in urban areas. Health care costs associated with sedentary lifestyles, which automobile use promotes, are also skyrocketing. [Source: Smart Growth America: Sprawl Shaves Years Off Your Life http://usa.streetsblog.org/2014/04/02/smart-growth-america-sprawl-shaves-years-off-your-life/]Studies have shown a direct correlation between a person’s health and their physical environment. University of Toronto researchers found that populations in less walkable neighbourhoods develop higher levels of diabetes, and are at greater risk of obesity and other chronic diseases.

Shifting our mobility investments towards active and sustainable modes of transportation will increase travel efficiency, save money, and help repair environmental damage already caused by decades of building our cities around the automobile. In 2011, the European Commission published its Roadmap to a Single European Transport Area targeting a 20% reduction in transport emissions by 2030 (compared to 2008 levels) rising to 60% by 2050 (compared to 1990). [Source: Towards Zero Carbon Mobility in Europe http://www.uitp.org/sites/default/files/Position_Papers/UITP%20position%20clean%20power%20for%20transport%20package_130628.pdf ]Supporting documents demonstrated that achieving these goals would require a combination of technology and policy measures to encourage a significant modal shift towards zero-carbon mobility. 


There are many policy instruments that can be used to reverse auto-dependence, and increase the feasibility of active and sustainable modes of transportation, including:

Pricing:  Many municipalities throughout the world have begun experimenting with pricing mechanisms that internalize the true costs of owning and operating an automobile. Fuel taxes, highway tolls, and raising the costs of parking have all proven effective methods for reducing automobile use. At the same time, more equitably distributing infrastructure investments among all transportation modes significantly increase the feasibility and efficiency of walking, cycling and public transportation. Compare, for example, the costs of building bike lanes compared with the costs of building car lanes. Doubling the width of a two lane arterial road costs $1.3 million/km. Constructing one kilometer of bike lane is approximately $20,000 if no road widening is needed, and $150,000/km if the road must be widened. Investments in bike lanes are not only financially prudent, but can also increase efficiency. In urban areas, where cars and bicyclists travel at similar speeds, bike lanes can accommodate 7 to 12 times more people per metre of lane per hour than car lanes. Pedestrian infrastructure such as sidewalks can handle approximately 20 times the volume of people per hour than roads for cars in urban traffic.

Policy + Regulation: Pricing tools must be coupled with policies and regulations that disincentives low density developments, which perpetuates auto-dependence. The built environment has direct influence over what modes of transportation we choose. Census data shows that reliance on automobiles significantly increases as you move further from city centres. Suburban households travel three times as many vehicle kilometers per year than their counterparts in denser urban areas. Complete communities where basic services and amenities are within walkable distances would drastically reduce GHG emissions. This requires higher density and mixed-use development, but it also demands planning with active and sustainable transportation users in mind. Street quality, path connectivity, street trees, and scenery are all aspects of the public realm that are identified as having a positive relationship with people’s decisions to walk or bike. Research has shown that 90% of the emissions of a typical 11-kilometre car trip occur in the first 1.6 kilometres. Therefore, replacing short car trips (2 kilometres or less) with walking, cycling, or public transit could have significant impacts on reducing overall emissions.

Responding to Changing Demands: Developing active and zero-carbon transportation systems is urgently needed to keep up with evolving demands and creating a symbiotic city. The rising costs of  automobile ownership and increasing environmental consciousness has meant that millenials are trading car trips for active modes of transportation where they can. From 2001 to 2009, the average annual vehicle miles travelled by 16 to 34 year-olds in the United States decreased by 23%. In the same time span, 16 to 34 year-olds made 24% more trips by bike, 16% more walking trips, and took 40% more trips by public transportation. [Source: http://visual.ly/new-american-transit]Adjusting for population growth, the total vehicle miles driven per year in the United States has decreased 8.9% since peaking in 2005. Meanwhile, innovations and alternatives to car ownership, such as care share programs, are helping to reduce unnecessary automobile trips. While promising signs, these behavioural shifts must be supported by leadership and policies that prioritize the efficiency and feasibility of active and sustainable transportation modes.

Transforming Existing Suburbs: Larger, more efficient public and active transportation systems will be instrumental in reaching zero carbon mobility in urban centres. Suburban communities, however, will remain reliant on the private automobile well into the future. Fortunately, market forces are rapidly changing in a way that will increase the demand for, and reliance on electric vehicles, while at the same time lowering dependence on fossil fuels for mobility. In many suburban municipalities, electric and fuel-cell vehicles are already leading the way to zero-carbon mobility. Several municipalities around the world are demonstrating that electric vehicles can complement public transportation systems by installing battery-charging infrastructure at commuter stations. At the same time, new infrastructure investments in rapid transportation systems are connecting suburbanites to city centres. 

Although for most consumers, electric cars are stillunaffordable, electric car technology is rapidly evolving and purchase costs are falling. Tesla Motors is one of the more innovative automobile companies closing the cost-competitiveness gap for zero-carbon vehicles. Fully recharging Tesla’s Model S, currently priced from $69,900, can take up to eight hours with a 240-volt home-charging system. New rapid charging stations under construction along highways in the US can provide 150 miles of driving for electric vehicles in less than 30 minutes.

Rather than waiting for electric and fuel-cell cars to reach average consumers, several suburban municipalities are taking a proactive approach to zero-carbon mobility. The South Bay Cities Council of Governments in California has introduced a neighbourhood electric car sharing program. Creating a zero-carbon mobility suburb is made all the more viable when electric car infrastructure is coordinated with public transit systems. The potential of such an approach is being piloted in the Bay Area, where the City Car Share program now provides 30 electric cars to its members. The vehicles are positioned throughout Hacienda, a square-mile residential and business development where nearly 18,000 people work, and 4,000 people live. The program is designed to connect residents and employees to the Bay Area Rapid Transit system. [Source: http://www.businessinsider.com/reinventing-the-suburbs-with-electric-cars-2013-10] Similar pilot programs around North America and Europe are collectively demonstrating the potential for the suburbs to reach zero-carbon mobility for short car trips (3km and under), without sacrificing the convenience of the private automobile.  


  1. Canadian Institute of Planners. Healthy Communities Practice Guide

  2. Transport Canada. Active Transportation in Canada: A Resource and Planning Guide (2012) http://www.tc.gc.ca/media/documents/programs/atge.pdf

  3. Victoria Transport Policy Institute http://www.vtpi.org/

  4. 8-80 Cities www.8-80cities.org