Mot-clé : Induced traffic
Thème : Intro
18 February 2011
Par : Saga Cité
The land use and town planning are the tools we use to shape our living environments and their structure. Therefore, they determine in large part our communities’ energy consumption patterns and they have an impact on many factors of greenhouse gas emissions (GHG), in particular:
- Building and maintaining facilities (type, size and choice of material);
- Transporting people and goods;
- Maintaining or losing natural spaces;
- Heating and air-conditioning of buildings.
The land use of a community sets characteristics for at least one or two generations. Highways, museums and neighborhoods are built to last for several decades. Their location and choice of material, for example, may have impacts that lasts for their entire life cycle. In addition to reducing the energy costs of community facilities directly, urban development has an effect on the lifestyle and therefore helps reduce GHG emissions at source.
Climate change can be dealt with in many ways. Part of the solution lies in technical innovations and everyday actions. However, the best way to overcome together the barriers we cannot overcome individually is to bring about significant changes in the way we plan urban development, in order to align it with the challenges we now face. This conclusion is reached by many, both locally (Jean Charest - in French) and in the rest of the world (Carfree France – in French).
The vicious circle of automobile dependency 
The arrival of the automobile disrupted the cities’ urban development. Dense cities, that were based on public transit and active transportation and where people had easy access to various services, proceeded to quickly spread out. The era of the tramway had already caused cities to expand beyond what nonmotorized travel modes previously allowed; but contrary to the car that would eventually replace it, the tramway helped establish relatively compact urban forms where active transportation kept its importance.
After the Second World War, with the car becoming popular, North America underwent a massive urbanization phase which happened to be based on what we now call sprawl, creating suburban areas located ever further from downtown. In this new context where density and accessibility were no longer priorities, zoning regulations were now oriented towards a strict separation of land uses in order to limit the inconveniences of certain activities. The urban structure changed and traveling distances increased. In the period between 1971 and 2006, where the population of the Quebec City census metropolitan area increased by 62%, the built area increased by 261% . These planning choices ensured that the car became an essential part of most people’s transportation needs.
This now results in chronic road congestion problems which governments usually try to solve by increasing road capacity. Unfortunately, this solution is short-lived and has a negative impact on the urban structure. In fact, the new roads attract new residential or commercial developments and generate new trips that will take up 50 to 90%  of the additional road capacity. This phenomenon, which is known as induced traffic, is integral in reinforcing the vicious circle of automobile dependency where the new roads develop their own congestion problems which will temporarily be solved by the same short-term solution.
Public transport, GHG emissions and oil dependency
Over the last decades, the urban sprawl has increased travel distances and motorized travel, and has created a growing automobile dependency that caused a drastic increase of GHG emissions.
Proof of this is the increase of the car to population ratio. Between 2000 and 2009 in Quebec, the number of motor vehicles rose by 24% while population growth was only 6.1% . The more vehicles on the road, the more total distance travelled increases. From 1990 to 2007, total distance travelled by motor vehicles in Quebec went from 50 to 71 billion kilometers .
During the same period between 1990 and 2007, while almost all of Quebec’s various industrial activities managed to reduce their GHG emissions, the road transportation industry increased them by 37% . Today, the transportation industry is accountable for 43% of the total amount of GHG emissions in the province, of which close to 80% is caused by road transportation of people and goods. To reach the Kyoto protocol objectives (and Quebec’s of 20% below 1990 levels by 2020) is to imperatively act on this sector.
The improvements in the energy efficiency of vehicles appear insufficient to reverse the trend. Firstly because of the growing share of light trucks and other large vehicles in the car fleet , and secondly because the gains from better energy perfomance are offset by a faster increase in travelled distances.
A costly dependency
The car-based spatial organization of cities has various negative impacts, among which are:
- In the Montreal region alone, congestion results in annual costs of 1.4 billion dollars .
- Urban sprawl and car-oriented infrastructure causes wastage of huge tracts of land.
- Asphalt-, concrete- and tar-made roads, bridges and parking lots have low albedos, which makes them absorb heat, creating urban heat islands and their associated negative health impacts.
- The resulting impervious surfaces eliminate the natural processes of water retention and filtration.
- Urban sprawl increases the costs of construction and maintenance of public networks and facilities, as well as energy consumption at the neighborhood level.
- The highways and expressways block and restrict walking and biking trips, creating no man’s land where walking is, if not dangerous, at least unpractical and uncomfortable.
- Increasing automobile traffic hinders social interaction and contributes to breaking up the social structure.
Reversing the trend: the logic of a compact city
When the urban structure adapts itself to the car, it becomes less and less compatible with other means of transportation that, in order to be efficient, need density.
The contribution of planning in improving the carbon footprint of our communities brings different benefits and takes into account the particular context of every living environment.
Since the 80s, the Smart Growth movement in North America has suggested a planning approach that focuses on the idea of a compact city. More recently, many cities provide planning examples that successfully implement the elements previously mentioned. This is the case, for example, for Stockholm in Sweden, and Portland in Oregon. There are also examples of model neighborhoods that are entirely built in accordance with the principles of the compact city. These ecodistricts, usually pilot studies that allow developers, builders and planners to develop skills and spread expertise, can lead to exemplary neighborhoods that become part of their city and offer an ideal living environment to their inhabitants. Well-known examples are the Vauban neighborhood, in Freiburg-im-Breisgau in Germany, and Hammarby, a neighborhood in Stockholm, Sweden.
There is no magic formula for the sustainable development of communities. It is fundamental that a large variety of elements and opinions be considered. That way, the various issues related to adequate land use planning can hopefully be dealt with appropriately.
-  Vivre en Ville, 2009. Le développement urbain viable au coeur de la stratégie québécoise de réduction des émissions de GES. (PDF – in French) ↩
-  Communauté métropolitaine de Québec, 2006. État de situation préparé dans le cadre de l’élaboration du schéma métropolitain d’aménagement et de développement (SMAD) AND Statistics Canada, Population and dwelling counts, for Canada, census metropolitan areas, census agglomerations and census subdivisions (municipalities), 2006 and 2001 censuses ↩
-  Victoria Transport Policy Institute, 2010. Rebound Effects : Implications for Transport Planning (TDM Encyclopedia) ↩
-  SAAQ, Données et statistiques 2009 (PDF – in French) et ISQ, 2009. Le bilan démographique du Québec ↩
-  Office of Energy Efficiency of Canada, 2008. 2008 Canadian Vehicule Survey Update Report ↩
-  MDDEP, 2009, Inventaire québécois des émissions de GES en 2007. (PDF – in French) ↩
-  Office of Energy Efficiency of Canada, 2009. Energy Efficiency Trends in Canada, 1990 to 2007. ↩
-  Board of Trade of Metropolitan Montreal, 2010. Public Transit: At the Heart of Montreal’s Economic Development. (PDF) ↩