Search Carbonrally

Promoted Challenge!

Wendy suggested this challenge and received 34 votes before it was promoted.

Challenge Activity

These people have all recently accepted this challenge.

05/16/13 CarbonReducer accepted this challenge, reducing CO₂ by 4 lbs so far.

05/01/13 Eastender Pam accepted this challenge, reducing CO₂ by 4 lbs so far.

04/29/13 Regina accepted this challenge, reducing CO₂ by 4 lbs so far.

04/29/13 ecomeister accepted this challenge, reducing CO₂ by 4 lbs so far.

04/27/13 gr8vince accepted this challenge, reducing CO₂ by 4 lbs so far.

Lowrider Featured on Jul 12, 2009

Alternative content

Challenge Details

• More mellow acceleration and stopping can increase highway mileage by over 30%
• 60 MPH is an optimal speed for fuel economy. Going 65 will lower your miles-per-gallon by 7%
• Wind drag caused by unused roof racks can reduce highway milage by 10%

You can’t say Carbonrally hasn’t tried to help you use less gasoline. We’ve challenged you to keep your tires properly inflated. We’ve challenged you to carpool. We’ve challenged you to stop unnecessarily idling your car. Now, with the price of gasoline on the rise, we’re prepared to do it again. Let’s take it up another notch and show we’re smart enough to drive smarter. You’ll burn less gasoline; save money; keep greenhouse gases out of the atmosphere. Smart? It’s a no-brainer!

This Featured Challenge is based on a number of terrific Challenge suggestions from our Challenge Workshop. Specifically, we’d like to give kudos to Wendy, as well as vienna101 and jonsfubar_60554 for suggesting that we all slow down, and Violet for suggesting we need to get the dead weight out of our trunks.

The Carbon Connection
American cars, vans, SUVs, and light trucks use over 9 million barrels of oil a day. That’s almost 400 million gallons of gasoline each day. The cost of a gallon of regular now averages nearly $2.60 nationally, and the price has been on the rise since January 2009. On average, that’s an about $127 or so per vehicle per month in gasoline expense. For many people, the number is much higher. For many people, that $127 is already too much.

With the cost of gasoline increasing, we all need to drive smarter and use less gasoline. But the cost in dollars isn’t the only reason. Close to 30% of the greenhouse gases released in the United States come from transportation. Of that amount, over 80% is produced by our vehicles driving on the roads (cars, trucks, buses) and burning gasoline or diesel. Each gallon of gasoline burned in an average car’s engine blows 19.4 pounds of CO2 out the exhaust and directly into Earth’s atmosphere. That means an average car emits 35 pounds of carbon dioxide every day! The less gasoline we burn, the better it is for our atmosphere.

There are many ways to improve your vehicle’s mileage so that you use less gasoline. For instance, the simplest way to get better mileage is to observe the speed limit. At speeds above 60 miles per hour, a car’s fuel efficiency drops off. You get fewer miles per gallon. For every 5 mph over 60 mph, your vehicle’s miles per gallon drops about 7%. On a 200 mile trip, an average car driving at 75 mph instead of 65 mph burns an extra 1.6 gallons, costs an additional $4.16, and releases an additional 30 pounds of CO2 into the atmosphere.

Getting It Done
So we are challenging you slow down. Reduce your speed by 5 mph when you’re driving on the highway this month. We are also asking you to drive less aggressively and to reduce the amount of unnecessary weight in your trunk.

Need help meeting this Challenge? Here are a few suggestions:

• Ratchet down the aggressive driving. And by “aggressive driving,” we don’t mean serious road rage. This is how you drive, what you do with your foot when you accelerate or brake. Stop stomping those pedals! Jackrabbit starts and hard braking habits are costing you mileage and money. Accelerate to driving speed at a little more leisurely pace. Don’t go full speed and then slam on the brakes; start to slow down earlier by easing off the gas and starting to brake gently from farther away. Making this one change to your driving style can save you as much as 33% on the highway and 5% in the city.   source
• Slowing down on the highway has its challenges. First, you have to be willing to be one of the slower cars on the highway. People might stare. That’s a psychological challenge. It helps if you remember that you wouldn’t get where you’re going all that much faster if you were going five or ten miles faster.
• The second challenge to driving more slowly is more serious. You don’t want to put yourself or others in danger by going too slowly. The ideal speed for higher gas mileage may be 60 mph, but that can be too slow for safety on many highways where the speed limit is 65 mph and the flow of traffic is going closer to 75 mph. If you’re going to drive at or under the speed limit on the highway, please drive in the right lane. And pay very close attention to your rearview mirror. You don’t want to get hit from behind by a car coming up fast behind you. For the purpose of this Challenge, let’s assume you’re lowering your highway speed by 5 mph. So, if you normally go 10 mph over the speed limit, bring that down to 5 mph over the speed limit.
• Have you got Prius envy? Hybrids and some other newer model cars have digital readouts on the dashboard that give you immediate feedback on your car’s miles per gallon. These sophisticated trip computers tell you if the way you are driving at that moment is giving you better or worse mileage — and that feedback goes a long way toward changing your driving behavior. If your car does not have one of these trip computers, you can install something like the ScanGauge II. It works on any car model year 1996 and newer.
• Carrying around an extra 100 pounds in your trunk can reduce your mileage by up to 2%. Of course you should always carry your spare tire, jack, and some tools. But be smart. Do you need the beach chairs and sand toys in your trunk all week when you won’t be going to the beach until next weekend? How long has that box of books for the library been in there? Do your golf clubs really need to go with you, everywhere you go? Check out what’s in your trunk and reduce what you carry to what you need to carry for that trip or that day.  source
• And if you have car roof racks for bikes or kayaks, don’t leave those on when they’re not in use. The extra drag caused by the air hitting those racks at high speeds can lower your mileage by as much as 10%.

Have you tried any of these methods yourself? Was it difficult to change your driving habits? What sort of difference did you see in your vehicle’s mileage? Share your experiences with fellow Rallyers in the Discussion section below.

Rules of the Challenge
This Challenge is intended for Rallyers who drive or ride in passenger cars, vans, SUVs, or light trucks. The Challenge asks you (or your driver) to: 1) drive less aggressively; 2) reduce your speed by 5 mph on the highway; and 3) reduce the amount of unnecessary weight in your trunk. By making these three changes to your driving habits this month, you will reduce your CO2 emissions by 48.4 lbs per week or 207.6 lbs for the month. This Challenge is repeatable after 1 month.

Learn More

100 great ecodriving tips from Ecomodder
Fueleconomy.gov: Gas Savings Tips
EcoDriving USA: EcoDriving Practices
FuelOurFutureNow: Lesson Plan – How Driving Behavior Affects Fuel Efficiency

See the Math
It’s time to see how all this comes out when the rubber meets the road. Let’s look at the known or estimated numbers being used for this Challenge:

• According to the EPA, the average American, non-commercial vehicle gets driven 12,000 miles per year. That’s 1000 miles driven each month.  source
• For the purposes of our math, we are using EPA estimates that the average non-commercial vehicle drives 55% of its miles in the city and 45% on the highway. (We know that your particular driving may not match those estimates, but we have to start somewhere.) Apply those percentages to the 1000 miles driven each month and you get 550 city miles and 450 highway miles driven each month.  source
• The EPA uses the 55 city / 45 city numbers to calculate average combined fuel economy numbers for various vehicles. For instance, they calculate that the average car on the road today gets a combined (both city and highway) average 23.9 miles per gallon each week. The miles per gallon numbers for SUVs and trucks are lower (17.4 mpg). Since we don’t know what you drive, we are using an average of vehicle types and going with 20.3 miles per gallon.  source
• Using the above numbers, we calculate that the average vehicle uses 27.1 gallons driving in the city each month and another 22.2 gallons driving on the highway.
• Now let’s look at the potential savings from the Challenge. Driving less aggressively decreases your gasoline use by 33% on the highway and 5% in the city. Since that 33% number is for the most leadfooted, aggressive highway driver and since we know none of your fellow Rallyers fits that description, we’re going to cut that number in half and use 16% for highway savings. Slowing down 5 miles per hour on the highway saves you another 7% on the highway. Finally, removing 50 pounds of extra weight from your trunk reduces your gasoline use by another 1% on both city and highway miles. If we add all those together, accepting this Challenge will mean that you reduce your gasoline use by 24% on the highway and 6% in the city.
• Next, apply the fuel reduction percentages to the gallons of gasoline burned driving on the highway and in the city. You reduce your highway driving gas consumption by 24%. Multiply 22.2 gallons by 24% to get 5.3 gallons. You reduce your city driving gas consumption by 6%. Multiply 27.1 gallons by 6% to get 1.6 gallons. The total gasoline saved by taking this Challenge is 6.9 gallons.
• The burning of 1 gallon of gasoline by the average car, van, truck, or SUV engine releases 19.4 pounds of CO2 into Earth’s atmosphere.  source
• Burning 6.9 gallons less gasoline in a month results in a CO2 savings of 133.9 pounds (10.7 gallons times 19.4 pounds CO2 per gallon of gasoline burned). At June 09 prices, it will also save you about $18 at the pump.

Of course, your car may be more fuel efficient than the average car on the road when these statistics were compiled. You may drive more or less than 1000 miles each month. You may drive all of your miles in the city and none on the highway. Numbers will vary. Just remember that the idea is to use less gasoline. Keep changing your driving habits for the better in order to cut back on the amount of gas you use. You’ll spend less at the pump and pump a lot less CO2 into the air.

Discussion 91 comments so far

KlnAir4U almost 3 years ago

Initially, when I first started driving my new Prius, I was doing a "pultry" 40 MPG. Then, I started experimenting with Hypermiling techniques. Nothing major, just easy stuff like keeping my tires' pressure up to the maximum rated pressure rating on the tire (44 PSI). Then, I started watching for Red lights a block or more ahead and gauging my speed accordingly. I kept my highway speed to the limit it just below it (I still got to my destination on time) and before I knew it, my average had gone to 60 MPG!! Now, I have an extra battery pack in my trunk and I'm getting around 150 MPG and over 1000 miles per tank.

SurlySteve over 3 years ago

I bike every where I need to go OPEC SUX