Live Green and Earn Points


Slow down on the road

By Jennifer Spero |
Save fuel, reduce emissions, and lower your stress level. On the highway, cutting your speed by just five mph can make a big difference in fuel economy; in town, "going with the flow" can reduce emissions and save on wear and tear.

Slowing down on the road not only keeps roadways safe and sane but improves gas mileage and curbs the volume of greenhouse gases emitted from automobiles.

How to slow down on the road

It's simple. Unless you're the proud recipient of several drag racing trophies, look to your grandmother for driving inspiration. Going ''under'' the posted speed limit isn't the solution, but taming that lead-casted foot is. A fuel-sensitive freeway speed suggested by experts and conservationists is 55 mph. Here's how to slow it down:

  • Ignore other drivers: Don't become beleaguered or succumb to feelings of auto-inadequacy if you sense the world is whizzing by you at 75 mph while you obey the posted 55. Disregard the sneerers, honkers, and tailgaters. Keep in mind, slow and steady wins the race — and saves at the filling station.
  • Cruise away. If your car has a cruise control option, use it on highway or freeway trips that require driving at a higher, constant speed. Driving with cruise control benefits, in this situation, fuel economy.

Need some more proof of the effectiveness of slowing down? Check out where tips on driving slower, less aggressively, and with cruise control are put to the test.

Slowing down on the road helps you go green because…

  • Fuel consumption increases dramatically once you exceed 60 miles per hour. Obeying the speed limit or slowing down conserves fuel and emits fewer pollutants into the atmosphere. Driving conservatively is also a safer option for you and fellow motorists.
  • Due to wind resistance, a driver's fuel economy can decrease by as much as 15 percent when moving at high speeds. Theoretically, for every 1,000 miles driven with 25 mpg fuel efficiency and gas at $2.50 a gallon, you could save $15 dollars at the pump by going 10 mph slower.[1]

Fifty-five mph is the recommended speed, and a limit that was enforced on the nation's freeways from the mid-1970s (due to the Arab oil embargo) until 1995. Current maximums vary by state. In some states, the urban interstate speed limit remains 55 mph while in other states it can be as high as 75 mph.

Americans use more than 100 billion gallons of gasoline each year. If that fuel were stored in a tank the size of a football field, the walls would have to be nearly 50 miles high.[2]

Every gallon of gasoline burned releases 20 pounds of carbon dioxide, making the transportation sector responsible for about a quarter of overall US carbon dioxide emissions.[3] And because no combustion is perfectly clean, cars are also a primary source of local air pollution.

Related health issues

Aside from the global-warming gas carbon dioxide, three major pollutants emitted by automobiles — hydrocarbons, carbon monoxide, and nitrogen oxide — also pose dire risks to human health. Specifically, when hydrocarbons and nitrogen oxide mix in sunlight and high temperatures, ground-level ozone is created. This leads to coughing, wheezing, and eye irritation, and can result in chronic lung problems. Carbon monoxide decreases levels of oxygen in the bloodstream and affects mental and visual functions.


automotive fuel economy: Fuel economy in cars is important because carbon dioxide emissions are directly related to the amount of fuel burned. "Miles per gallon," or mpg, is the way most Americans measure fuel economy, while other countries may use liters of fuel per 100 km traveled. To measure your fuel economy, fill your tank and reset the odometer. At your next fill-up, divide the miles traveled by the amount of fuel needed to refill the tank. For the 2008 model year, the EPA has updated its fuel economy test to reflect today's higher speeds, increased use of air conditioning, and other factors. In many cases, the published "window sticker" mpg values will be lower.

External links


  1. Car Talk's Guide to Better Fuel Economy
  2. Energy Information Administration - "Household Vehicles Energy Use: Latest Data & Trends"
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