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STM - Society in motion

By taking the bus instead of your car, you are cutting your polluting emissions by more than half. May 2, 2010 

Green actions

By taking the bus

When comparing the emissions of a car ride with those of a bus ride, several data are taken into account:

  1. the average emissions of a car per travelled kilometre, as published by Transport Canada;
  2. the average number of persons per car according to the Origin-Destination survey (1.25 person);
  3. the emissions by all STM buses for all hours of transit service;
  4. bus ridership and the average length of a bus trip (km-passenger).

Polluting emissions include :

  1. carbon monoxide (CO)
  2. nitrogen oxides (NOx)
  3. sulphur dioxide (SO2)
  4. volatile organic compounds (VOC)
  5. total suspended particulates (TSP)

Polluting emissions are not produced in the same proportion for buses and cars.

Our calculations show that, when combining all hours of STM service, they are 2 to 10 times lesser for a bus than for a car, depending on the pollutant.

During rush hour, emissions are 7 to 44 times lesser for a bus than for a car. This is based on an average of 65 passengers per bus, which is equal to 50 cars (65 persons divided by 1.25).

The Orange Line Also Is Green May 1, 2010 

Green actions

The Orange Line Is Also Green

Together, passengers using the Orange line help prevent the emission of 89 562 056 cubic metres of CO2 each year. That’s 48 times the volume of the Olympic Stadium.

The math leading to this result, which is an average of course, is based on several factors.

  1. The Origin-Destination survey, conducted in 2008, helped to determine that a client riding the STM network travels an average distance of 8.3 km. We also learn that 1.25 is the average number of passengers in a car.
  2. These calculations take into account all GHG emissions by STM vehicles for all hours of transit service, or an average of 112 g of CO2 per km/passenger for the bus and 0 for the métro. Conversely, a car trip produces 216 g of CO2 , or some 270 g per km/1.25 passenger.
  3. Also taken into account is the fact that some people only use the bus (30%) or the métro (40%), while others use a combination of both.
  4. GHG emissions are usually measured by weight. Under normal conditions of temperature and pressure, a ton of CO2 takes up a volume of about 550 cubic metres. For an idea of what that means, it’s roughly equal to a pool measuring 10m x 25m x 2m deep.
  5. The average yearly ridership of a bus route is determined by readings taken each day aboard every bus. As for the metro, total rides are compiled from data taken at the turnstiles.

By taking all these factors into consideration, and assuming that all passengers had carried out the same trip by car (with an average 1.25 person per car), we can determine the volume of prevented emissions.

Going Green All The Way May 1, 2010 

Green actions

Going green all the way

Collectively, passengers using the help prevent the emission of cubic metres of CO2 each year. That's times the volume of the Biosphere on Sainte-Héléne Island

Collectively, passengers using the 51 bus route help prevent the emission of 4 254 806 cubic metres of CO2 each year. That’s 19 times the volume of the Biosphère on Sainte-Hélène Island.

The math leading to this result, which is an average of course, is based on several factors.

  1. The Origin-Destination survey, conducted in 2008, helped to determine that a client riding the STM network travels an average distance of 8.3 km. We also learn that 1.3 is the average number of passengers in a car.
  2. These calculations take into account all GHG emissions by STM vehicles for the entire time transit service is provided, or an average of 112 g of CO2 per km/passenger for the bus and 0 for the métro. Conversely, a car trip produces 208 g of CO2 , or some 270 g per km/1.3 passenger.
  3. Also taken into account is the fact that some people only use the bus (30%) or the métro (40%), while others use a combination of both.
  4. GHG emissions are usually measured by weight. Under normal conditions of temperature and pressure, a ton of CO2 takes up a volume of about 550 cubic metres. For an idea of what that means, it’s roughly equal to a pool measuring 10m x 25m x 2m deep.
  5. The average yearly ridership of a bus route is determined by readings taken each day aboard every bus. As for the metro, total rides are compiled from data taken at the turnstiles.

By taking all these factors into consideration, and assuming that all passengers had carried out the same trip by car (with an average 1.3 person per car), we can determine the volume of prevented emissions.