Warming Signs: Calculating Your Transportation “Footprint”

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Warming Signs: Calculating Your Transportation “Footprint”

Often, when we talk about climate change, it seems like a far-off scenario. We talk in terms of saving the planet for future generations and predict disruptive sea level rise within the century. But the effects of climate change are already felt around the world; future changes will only intensify them.


Combatting climate change can sometimes feel impossible, especially for individuals. You might find yourself wondering what you could possibly do that would make a difference? Well, more than you’d think. The United States is responsible for about 16 percent of the world’s greenhouse gas emissions. Finding ways to cut back on your footprint can have a huge impact.

You probably know that reconsidering your transportation habits is an important way to start making individual changes. But how and why, and what can you do to be more efficient?

In 2014, transportation accounted for 26 percent of U.S. greenhouse gas emissions—the second biggest source of emissions after electricity. Between 1990 and 2006, transportation emissions rose by more than 25 percent—nearly half of our total increase in emissions. Cutting back on this trend not only reduces our dependence on fossil fuels; it also lessens the greenhouse gases we’re adding to the atmosphere. Win win! There are many ways to change our transportation habits—whole books have been written about it. But here are a few quick pointers.


Your Footprint

The average American produces about 4.7 metric tons of carbon dioxide every year. Those estimates are based upon an average fuel economy of 21.6 miles a gallon, and a driver who travels about 11,400 miles a year.

Cars 2.pngGraphic courtesy of the EPA

Although carbon dioxide is the main greenhouse gas emitted by cars, vehicles also produce methane, nitrous oxide, and, sometimes, hydrofluorocarbon emissions from leaking air conditioners and refrigerator trucks.

If you drive an old pickup truck 5,000 miles a year, or a Prius for 50,000 miles, your emissions will likely be a bit different than the average. If you really want to go deep, try calculating your personal carbon footprint. This can give you a better idea of which areas you might want to improve, and in which areas you’re just naturally efficient.


Biking and Walking

Whenever possible, it’s always a good idea to ditch the combustible engine in favor of human power. The cool thing about both walking and biking is that they don’t just affect your emissions. When there are fewer cars on the road, other commuters spend less time idling in traffic jams—so their emissions drop, too. (More on idling later.)

There aren’t many stats on choosing to walk over driving, probably because it seems so straightforward and because walking is not a perfect solution for those who live too far from work or school. However, much of the research on bicycles applies to walking as well.

If urban residents switched to bicycles and even electric bikes for only 10 percent of their trips around town, citywide emissions would decrease by about 11 percent—and save about $24 trillion in infrastructure costs and other expenses by 2050, a 2015 report found. Although bikes account for 6 percent of all trips in cities around the world, the U.S. trails behind with only 1 percent of urban travel happening by bike. But amping up bike use could save us 2 gigatonnes of carbon dioxide emissions in the next four decades—no laughing matter.

Also, you can sing Queen at the top of your lungs and no one is allowed to judge you. That’s a true fact.


Public Transportation

Cars 3.pngGraphic courtesy of the EPA

This is a great option for those of us who live in cities and towns offering public buses and trains. It’s way less work than driving. You can watch a movie, bring a book, write the next great American chart-topper—and save some money and the environment.

According to the American Public Transportation Association (APTA), if you normally commute 20 miles roundtrip, switching from a car to public transportation would reduce your carbon dioxide emissions by 4,800 pounds every year—which is the same as lowering a two-person/two-car household’s emissions by 10 percent. Simply by eliminating one of those cars, you can save up to 30 percent of carbon dioxide emissions.

The association also notes that switching to public transport saves you an average of $6,251 per year—and that number is only rises as fuel prices do.

In total, APTA estimates, public transportation can reduce carbon dioxide emissions alone by 37 million metric tons every year. As with biking and walking, using more public transport relieves traffic congestion for others who are stuck behind the wheels of their own moving (or idling) vehicles. Plus, you won’t be the only one ditching your car. APTA reports that public transportation ridership has gone up 30 percent in the last 20 years.



Maybe the bus or bike aren’t for you, but you’re still convinced you need to make a change. Enter ride-sharing. Here in the suburbs of Washington, D.C., we have the option to carpool with strangers (called “slugging”) into the city. This practice makes use of high-occupancy vehicle (HOV) lanes, an important avenue for reducing the number of cars on the road.

Slugging and other informal carpooling is free. If you don’t mind spending a bit of money, there’s Uber Pool, plus short-term rentals like Zipcar, Enterprise, and others. Or you might have a group of friends who can work out a car-sharing agreement.


More Efficient Driving

Sometimes, though, you need to get behind your own wheel. What can you do then?

If you really want to change your emissions while staying on the road, consider buying a more efficient car, like an electric or hybrid vehicle. The Department of Energy has a pretty cool calculator for emissions savings based on state and national averages. Drivers in New York, for instance, would go cut their emissions in half by switching to a hybrid car; electric-car owners see their emissions drop a whopping 80 percent.

But if you’re not in the market for a new ride, you can still make improvements. Simply maintaining your car well can reduce emissions. Get regular tune-ups and maintenance, and use the recommended grade for oil in order to make sure your engine is running at its maximum efficiency. Making sure your tires aren’t under-inflated will improve your fuel economy and result in fewer emissions—not to mention reducing wear and tear, which saves you money.

It’s not just what you drive; how you drive can also make a difference. As mentioned earlier, idling is also a source of emissions. Try to avoid commuting in dense, stop-and-go traffic. If you’re going to be somewhere for more than 10 seconds, it’s actually more efficient to turn off the car and restart it later. Aggressive driving, like rapidly accelerating and then braking, can lower your gas mileage by 15 to 30 percent on the highway and 10 to 40 percent in stop-and-go traffic. Turning on cruise control as much as possible can also make your driving more efficient.


Don’t Leave Home

OK, don’t become a hermit. But if telecommuting is an option for you, it can really decrease your emissions. According to Global Workplace Analytics, 50 percent of working Americans could telecommute. If they worked from home half the time, emissions would fall by 54 million metric tons every year. That would be like removing 10 million cars from the road. Plus, think of all the gas money saved; in the same scenario, we’d keep 640 million barrels of oil out of our tanks each year.

Another option is living closer to where you work (or working closer to where you live). Anything to shave off those extra miles!

As with all of these suggestions, you don’t have to go all or nothing. Even the occasional change makes a difference; leaving your car behind just two days a week can reduce your emissions by an average of two tons a year. And that’s, well, quite a good start.

Top photo courtesy of Bike East Bay
Lead image courtesy of Thomanication

Melody Schreiber is a freelance journalist based in Washington, D.C.