**This page provides information on calculation methodology, assumptions and sources of data.**

**Calculations**

**Auto CO2 Emissions**

Emissions = (2 x the one way trip distance x the number of auto trips per week x type of auto CO2 emission factor x number of weeks in a school year) / the number of carpool passengers

**Bus CO2 Emissions**

Emissions = (the one way trip distance x the number of bus trips per week x bus CO2 emission factor x number of weeks in a school year)

**Total CO2e Emissions**

Total CO2 Emissions = auto CO2 Emissions + bus CO2 Emissions

**Distance Calculation**

Walk Distance = the one way trip distance x number of waking trips per week x number of weeks in a school year

Bike Distance = the one way trip distance x number of bike trips per week x number of weeks in a school year

Auto distance = 2 x the one way trip distance x number of auto trips per week x number of weeks in a school year

Bus distance = the one way trip distance x number of bus trips per week x number of weeks in a school year

**Fuel Use Calculation**

Fuel use = Auto distance x selected auto type fuel efficiency rating;

**Calories Calculation**

Calories burned = (Walk distance x walking calories per kilometre or mile) + (Bike distance x biking calories per kilometre or miles)

**Fuel Cost Calculation**

Fuel Cost = Cost of fuel per litre or gallon x fuel use

**Fuel use and CO2 Emissions Coefficients
**Source: NRCanada 2011 Private Vehicle Fuel Efficiency Guide using the city driving fuel efficiency and emissions coefficients.

http://oee.nrcan.gc.ca/publications/transportation/fuel-guide/2011/energuide-label.cfm

Hybrid – Based on a 2011 Honda Civic with a 1.3 litre engine

Litres per kilometre = 0.047, CO2 emission factor = 0.104

Gallons per mile = 0.020, CO2 emission factor = 0.371

Compact – Based on a 2011 Toyota Corolla with a1.8 litre engine

Litres per kilometre = 0.078, CO2 emission factor = 0.156

Gallons per mile = 0.033, CO2 emission factor = 0.557

Midsize – Based on a 2011 Nissan Altima with a 3.5 litre engine

Litres per kilometre = 0.104, CO2 emission factor = 0.207

Gallons per mile = 0.044, CO2 emission factor = 0.739

Fullsize- Based on a 2011 Ford Taurus with a 3.5 litre engine

Litres per kilometre = 0.117, CO2 emission factor = 0.223

Gallons per mile = 0.050, CO2 emission factor = 0.796

Minivan – Based on a 2011 Dodge Grand Caravan with a 3.3 litre engine

Litres per kilometre = 0.122, CO2 emission factor = 0.237

Gallons per mile = 0.052, CO2 emission factor = 0.846

Truck – Based on a 2011 Ford F150 FFV with a 5.0 litre engine

Litres per kilometre = 0.139, CO2 emission factor = 0.276

Gallons per mile = 0.059, CO2 emission factor = 0.985

SUV – Based on a 2011 Chevrolet Tahoe with a 5.3 litre engine

Litres per kilometre = 0.144, CO2 emission factor = 0.281

Gallons per mile = 0.061, CO2 emission factor = 1.003

Bus – Based on a typical transit bus with averaged ridership

Source, Translink BC;

Metric CO2 emission factor = 0.0586

Imperial CO2 emission factor = 0.209

**Other Coefficients list:**

Calories burned per kilometre walked = 27;

Calories burned per mile walked = 43;

http://walking.about.com/library/cal/uccalc1.htm

Calories burned per kilometre biked = 11;

Calories burned per mile biked = 18;

http://www.sparkpeople.com/resource/calories_burned.asp

*Note: The calories burned values in the iPad version 1.0 are incorrect and will be updated to these values in August 2012.*

Weeks in a school year = 37;

Default fuel cost per litre = $1.40;

Default fuel cost per gallon = $4.00