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Emissions From Heavy Diesel Vehicles

GHG Emissions from Heavy Vehicles

High Carbon Impact

line_of_trucksHeavy vehicles are one of the fastest growing sources of carbon emissions in Canada. Defined as trucks and buses weighing at least 4.5 tonnes, heavy diesel vehicles represent only 4% of onroad vehicles, but they contributed 29% of carbon emissions from onroad transportation sources in Canada in 2007.

Energy use is increasing rapidly within the heavy diesel vehicle segment. Between 1990 and 2007, energy consumption related to goods movement by truck increased 159%, representing the second fastest growing area energy end use in Canada. These vehicles also contributed more than half of the growth in greenhouse gas emissions from on-road sources since 1990. Future efficiency gains are expected to only partly offset projected increases in heavy truck activity.

Which Provinces are Most Affected?

Four provinces account for more than 80% of onroad heavy diesel vehicle use: Alberta, British Columbia, Ontario, and Québec. In each case, a small percentage of vehicles contribute a disproportionate share of carbon emissions.

Heavy Diesel Vehicles as Percent of Onroad Vehicles in Province Heavy Diesel Vehicle Share of Province’s Onroad Carbon Emissions
Alberta 8% 35%

British Columbia



Ontario 3% 25%



Note: All values quoted are from Environment Canada's National GHG Inventory with reference to Statistics Canada's Canadian Vehicle Survey.

Increasingly stringent diesel emission standards and the use of ultra low sulphur diesel have significantly reduced  tailpipe emissions from new heavy diesel vehicles. These standards have no impact on carbon emissions. Carbon is not currently regulated as a tailpipe emission for heavy vehicles, but both Canada and the United States have announced their intention to regulate carbon from heavy vehicles by 2014-2015.

Potential Role for Natural Gas

Pierce_Transit2_Seattle_CNG_Transit_BusesCanada has committed to reduce carbon emissions 17% below 2005 levels by 2020. This goal is equivalent to a 127 megatonne reduction of which an estimated 34 megatonnes would theoretically need to come from transportation sources. Based on the current vehicle population mix, this would suggest a 6.6 megatonne decrease is needed from medium- and heavy-duty trucks and buses.

Given the increasing availability of factory-direct trucks and buses combined with the lower carbon nature of natural gas, increased use of natural gas in transportation could help Canada achieve its carbon reduction goals. For example, if 5% of the heavy vehicles in Canada operated on natural gas, this would result in an 825 kilotonne annual reduction in carbon representing 13% of the transportation portion of Canada’s 2020 target.