Daly City's Green Vision - City of Daly City

To calculate emissions, the survey collected the following information:
The number of days and number of miles employees drive alone to work (one-way) in an average week
The number of days they carpooled and how often they drove the carpool in an average week
The vehicle type of their vehicle and the type of fuel consumed
These weekly data were then converted into annual VMT estimates by the following equation:
Number of days driven to work/week x to-work commute distance x 2 x 48 weeks worked/year
Actual CO 2 e emissions from respondents’ vehicles were calculated by converting vehicle miles traveled per week
by responding employees into annual fuel consumption by fuel type (gasoline, diesel). The VMT data collected
were converted to fuel consumption estimates using fuel economy of each vehicle type.22
ICLEI then extrapolated estimated fuel consumption to represent all 811 of Daly City’s employees in 2005. This
was a simple extrapolation, multiplying the estimated fuel consumption number by the appropriate factor to
represent all current employees. For example, if 33.3 percent of employees responded, fuel consumption numbers
were tripled to estimate fuel consumption for all employees. This is not a statistical analysis and no uncertainty has
been calculated as there is uncertainty not only at the extrapolation point but also in the calculation of actual
emissions. Therefore, the resulting calculated emissions should be seen as directional and not as statistically valid.
22 Fuel efficiency estimates from www.fueleconomy.gov, EPA Green Fleets Guide and other national sources.
2005 Daly City Government Operations Greenhouse Gas Emissions Inventory XVI