Impact of Transportation Actions (Box 2)
Avoided CO2 emissions from driving less
For gasoline-powered cars, burning one gallon of gasoline leads to 20 pounds of CO2 emissions (1). For electric vehicles, avoiding ten kilowatt-hours of electricity use in California leads to about 12 pounds of CO2 emissions reductions (2,3). This means that every time you choose to drive less, you emit less!
How much? The EPA tracks fuel economy for the vast majority of gas and electric cars (4), which means that we were able to calculate personalized savings profiles for each Carbon Bootcamp participant. A couple of details… If you did not specify a year then we used the latest model year available. If you did not specify a trim level, we used the trim level with the highest (i.e., best) fuel economy.
For those of you with gasoline powered vehicles, the CO2 emissions from driving your cars ranged from 6 to 11 pounds for every 10 miles driven.
For those of you with hybrid vehicles, the CO2 emissions from driving your cars ranged from 4 to 5 pounds for each 10 miles driven.
For those of you with electric vehicles, the CO2 emissions from driving your cars ranged from 3 to 4 pounds for every 10 miles driven.
A couple of special cases... One Carbon Bootcamp alumnus owns a 1989 GMC Electric G-Van. It’s a piece of EV history, but given its weight, its age, and the battery technology at the time, driving it does lead to 8 pounds of CO2 emissions for every 10 miles.
Also, one other alumnus drives a hydrogen fuel cell vehicle! A Toyota Mirai. This car uses 0.76 kg of hydrogen fuel for every 100km (5). Using the most optimistic estimate for how the hydrogen fuel is produced and the conversion factors we derived from the Union of Concerned Scientists (6), we calculated emissions at 4 pounds of CO2 emissions for every 10 miles driven.
Last but certainly not least, for those of you who listed something other than a car as your primary vehicle, we used fleet-average fuel economy for the US (24.7 mpg) (7) to calculate the CO2 emissions you are avoiding. This worked out to 8 pounds of CO2 per 10 miles not driven.
Avoided CO2 emissions for Box 2 Code Words
CARPOOL - TAKE A CAR OFF THE ROAD
To calculate the avoided CO2 emissions from carpooling, we divided your vehicle's CO2 emissions in half, assuming that you are carpooling with one other driver (or giving a ride to that driver's kids) and that their vehicle is similar to yours. If we use this rule of thumb and the fleet-average fuel economy for the US, that's 4 pounds of CO2 emissions avoided for every 10 miles.
TRANSIT - USE MASS TRANSIT, WHETHER PUBLIC OR PRIVATE
Calculating the avoided CO2 emissions from using mass transit is not straightforward, because it depends on a variety of factors including the type of transit (e.g., bus, light rail, vanpool) and also on the fraction of seats that are full (8). Under ideal conditions, using transit saves up to 90% of CO2 emissions (8), so we decided to keep things simple and the auto-response you have been receiving lists the savings as equal to the CO2 emissions of your primary vehicle. If we use this rule of thumb and the fleet-average fuel economy for the US, that's 8 pounds of CO2 emissions avoided for every 10 miles.
ZERO - GET TO WHERE YOU NEED TO GO WITHOUT EMITTING ANY CO2 (e.g., WALKING, BIKING, JOGGING, SCOOTING)
However you get to where you are going, if you are not emitting CO2 (or hardly any in the case of electric scooters or electric-assist bikes), then you are avoiding emissions at the rate of your primary vehicle! If we use the fleet-average fuel economy for the US, that's 8 pounds of CO2 emissions avoided for every 10 miles.
PUTTING IT ALL TOGETHER
Households in the Bay Area emit 44.3 metric tons of CO2 equivalent per year on average (9). Of that, 15 tons comes from transportation (9), which is 88 pounds per day. Every time you avoid 10 miles of driving (and use the code words CARPOOL, TRANSIT, NEW, ZERO, and 48HOURS) you are reducing your footprint by 10% for that day! Part 2 of the Bootcamp only runs for two weeks, so we are not tracking "big ticket" items like airplane trips, but that's clearly another great place to cut emissions...
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