A vehicle will use more fuel when traveling faster and at a higher rpm. However stating that all vehicles will use a specific amount of extra fuel for every 1 MPH is a false statement. Fuel use is dependent upon the make and model of the vehicle and how aerodynamic the vehicle is. I bet my Toyota Solara won't use as much extra fuel going 85 versus 55 as someone driving a big (not aerodynamic) large truck. The truck will require extra energy to overcome the greater wind resistance. My car is more aerodynamic and won't require as much energy to overcome the wind resistance traveling at a higher speed. I will use more fuel but it's not the stated specific amount some people like to quote that everyone will use.


I read an article in a local paper that stated the same thing. In fact for cars made more aerodynamic and made for faster speeds, the article stated the fuel use was only about 3 to 5 percent higher. If I'm in a hurry, I'd rather spend an extra dollar to get to my destination a half hour to hour earlier. It would save me fuel if those who want to go only 55 on the interstate try to stay on roads where the speed limit is 55 instead of 70. Traveling 55 on the interstate causes traffic congestion and when these people try to pass someone going even slower, they cause a lot of other drivers to hit their brakes and waste gas accelerating again. Of course I guess that's the American way. You can talk about how much gas you saved traveling only 55 mph on an interstate where the speed limit is 70 and you caused all kinds of traffic congestion and made countless other drivers hit their brakes, then reaccelerate wasting fuel in their vehicles. Then you're happy telling everyone how much you saved.

Originally posted by TheHunted
Actually there is nothing wrong with my math. Not all vehicles have the same size fuel tank. The less fuel economy for the vehicle the larger the tank.

For example I have an 85 Olds Delta 88 that gets 20 mpg but also has a 25 gallon tank. My Lesabre has one that is 15 gallons.

So I'm sure your friends vehicle may have a pretty decent size fuel tank. Am I wrong?

I was really trying to be a smart###, but you seem to have missed it anyways. You stated that for every mph over 65 you lose 1 mpg. This is a very simplistic way to look at it and it's not right. Using your method, a car that gets 20mpg will lose 1 mpg every mph over 65 so at 85mph it's now getting 0 miles per gallon.

I did some highway driving last night and paid attention to my tackometer. My car seems to coast at 2k rpms at around 72mph. Am I wrong in assuming rpms is what actually determines your mpg?

Why don't people understand that the main cause of the high gas prices is inflation? And because of the demand on oil they are able to be the first to adjust for the inflation? Sure there are other factors, but we've had supply and demand issues in the past as well and still the price never went up this much.

The price of oil goes down, so does the price of gold and other commodities. Is this just pure coincidence?

You can't spend a trillion dollars on a war printing up new money and not expect the prices of vital resources to compensate and go up. Correct me if I'm wrong here, but the price of oil has tripled. Have we suddenly lost 300% of oil supply?

I can't believe people don't realize this.

According to Lord Barrack Hussein Obama (The Messiah) His Majesty

1. Inflate your tires to the proper rate

2. Tune up your vehicle

3. We can save more on oil then all the offshore drilling or driling in ANWR

LMAO What a joke he is.

Sorry, had to add that in.

Driving the speed limit makes sense to me, why I do all the time now.

Yes, I drive a big Ford Truck wouldn't trade it for nothing.

If America would build more refineries and drill here now, we would see a collapse of gas prices.... PERIOD.

Let the tree hugging crowd eat dirt! We (America) can become energy Independent and stop making World policy regarding oil. (Middle East, Russia, etc.)

My name is VDOG.45 and I approve this message.

so if they raise the prices to 8$ a gallon, we should drive at 35mph on the highway.


YOU SEE the gap in your logic.

College Education rules.

Originally posted by TheHunted
I'm not saying that sensible driving will solve the fuel crisis. I do believe that automobiles are number in consumption of oil. Drivers are pretty much giving away money to the oil tycoons. Why give them free money when we are the ones being ripped of.

Lets prove that our demand is not the reason for sky rocketing prices but is due to greed and power.

why not just use ethonal when you can and keep the money here at home, than sending it over seas. look at brazil they don't import 1 drop of oil they run on ethanol they are truly energy independent. they exportt all of there oil. the food crisis becuase of energy demands is false, because there are endless things to make ethanol out of , and also the oil and gas companies spent over 1 billion $ to stop this from coming to market.

I live in California and commute to work 30 minutes away and people have slowed down. I used to drive 80mph consistently before prices skyrocketed. Now down between 65-70mph. Also, coasting into stop lights a lot earlier, drafting when I can, and accelerating slower from a stop. Getting about 20-30% more miles out of each tank than before so it does help.

I've been driving this same route for 10 years now and the one thing I've noticed this year is the change in the habits of the highway patrol. When I used to go 80mph, there were only a couple spots on the road where I knew the CHPs liked to hide. It was simple to slow down right before these spots and then pick right back up. Now, they are changing their routines, using speed traps with multiple officers on the side of the road, and picking spots where the speed limit drops considerably or where there is a lack of visibility like when coming over a hill. It's obvious they have to do this because they are not catching as many people speeding, which means less money for the city or county. It costs the CHPs a lot of gas to patrol, so now they are sitting on the side of the road in tricky spots trying their best to nab someone not paying attention to a change in speed limit or an inadvertent acceleration due to coming downhill.

It makes me wonder how strict they are going to get as the price at the pump bites a little deeper. It wouldn't surprise me if 1mph over the limit will truly become a punishable offense someday.

Originally posted by BlueTriangle

Originally posted by TheHunted
Actually there is nothing wrong with my math. Not all vehicles have the same size fuel tank. The less fuel economy for the vehicle the larger the tank.

For example I have an 85 Olds Delta 88 that gets 20 mpg but also has a 25 gallon tank. My Lesabre has one that is 15 gallons.

So I'm sure your friends vehicle may have a pretty decent size fuel tank. Am I wrong?

I was really trying to be a smart###, but you seem to have missed it anyways. You stated that for every mph over 65 you lose 1 mpg. This is a very simplistic way to look at it and it's not right. Using your method, a car that gets 20mpg will lose 1 mpg every mph over 65 so at 85mph it's now getting 0 miles per gallon.

I did some highway driving last night and paid attention to my tackometer. My car seems to coast at 2k rpms at around 72mph. Am I wrong in assuming rpms is what actually determines your mpg?

I agree that the formula can't work. My truck get 12.8 mpg. I have about a 25 gallon tank. So, if I'm running, oh, 80 mph, according to this I can't go any further than 25 miles because I'd be empty. I don't know about the 55 mpgs at 5500 rpms in the civic, but I do know that I've driven more than 25 miles at 80 mph and I still had plenty of gas.

Vehicles that differ in design are going to produce varying results when driven at differing speeds and at different R.P.M.s. The trucks and S.U.V.s are going to suffer a greater loss in fuel consumption at higher road speeds due to poor aerodynamics, rolling resistance, and mechanical friction. They are troubled in stop and go driving by drive train and overall weight. Trucks are great vehicles to use for moving heavy loads efficiently but are not really designed to be driven without a load. The main reason for the popularity is that due to federal laws. Trucks are given a break on meeting the projected M.P.G. guidelines and therefore provide larger profits for the auto industry and oil companies. Technological advances in engine management systems, aerodynamics, engine designs and synthetic lubricants are making large contributions providing more efficient vehicles that will go farther on less fuel and still provide more horse power than the cars of the past. The one thing that is going in the wrong direction is the newer cars can weigh up to 20% more than cars that provided the same engine displacement and proportional size 25 years ago. This difference is even more pronounced in cars for the U.S. market due to crash testing and safety engineering. More than anything else, a change in the aggressive driving habits of a large portion of the people on the road would make the biggest change in fuel consumption and safety concerns.