ABSTRACT
The North American discourse on compact cities and sustainability is strangely deficient in its consideration of what could prove to be its biggest hurdle: heavy gasoline and diesel-fuelled vehicles necessary to move freight, carry transit passengers, collect garbage, and maintain urban infrastructure. Congestion in the compact city is a serious matter when considering the place of heavy vehicles in the scheme of things, A considerable body of evidence supports the claim that the major force driving the dispersal of urban activities throughout most of the century is the avoidance of congestion. The overwhelming problem with heavy vehicles, however, is CO2, which comprises 94-99 per cent of emissions. Combustion in turn accounts for 70-80 per cent of life cycle energy, including the manufacture and distribution of heavy vehicles. Considerable progress has been made in the last decade to improve the engine efficiency of heavy vehicles.
