It may not be fun, but we all know that slower driving speeds are a good way to maximize fuel economy on the highway. To help prove this point, Consumer Reports did a series of tests to see exactly how much better a vehicle's fuel economy is at varying speeds. CR used five cars (Honda Accord four-cylinder, Toyota RAV4 and three different Ford Fusion models), which were each tested at 55, 65 and 75 miles per hour to determine the variations in fuel economy.

Not surprisingly, each car surpassed its fuel economy estimates at the slowest speeds. Econ for each also drops off considerably as the speeds increased. Driving the extra 20 mph will knock about an hour off of a 200-mile highway drive, but the test shows that it will also burn an extra two gallons of gas. Calculated out for a 1,000-mile road trip, we see up to 10 gallons of gasoline could be wasted. It would have been interesting to see how a diesel performed in this test, or even how Texas' new 85-mph toll road plays into this topic.

A couple interesting side notes in this tests include the four-cylinder Accord getting the same highway fuel economy at 55 mph as the Fusion Hybrid. Still more impressive, even at 75 mph, the Accord was still getting close to its EPA numbers (depending on which transmission was being used).


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  • 262 Comments
      idodeco2
      • 1 Year Ago
      Lets not forget the expense of speeding ticket and traffic school, higher insurance rates, etc.!
      BryanGx
      • 1 Year Ago
      There's a simple rule of aerodynamics: drag from wind resistance increases exponentially to speed. That means if cruising at 30 mph generates "x" amount of wind drag, doubling the speed to 60 mph will generate "4x" of wind drag--four times the drag, not simply double. The faster you go, the more crushing the drag penalty. There's obviously a noticeable difference between 55 and 75, especially for poorly streamlined vehicles like SUVs.
      2 wheeled menace
      • 1 Year Ago
      Aerodynamic drag increases at the square of velocity.. a realtime fuel economy meter like the a scanguage II can tell you the truth about this :)
        brotherkenny4
        • 1 Year Ago
        @2 wheeled menace
        Yes, but the self perceived manliness (imagined prowess) of the typical follower male also goes as the square of the velocity, as well as being directly proportional to the vehicles resemblence to a true competition vehicle. Well, that and how loud the exhaust is. I think the testosterone of simpletons will always trump mathematical relationships. And, it's a pretty easy target for advertisers to tweak too.
          • 1 Year Ago
          @brotherkenny4
          [blocked]
      FoxJ30
      • 1 Year Ago
      I'd like to see the effect a higher gear would give me. Most cars turn about 2000rpm at between 50-60mph, I'd like to see a car turn 2k rpm at about 70mph. Sure, you'll never use that gear unless you're actually on the freeway, but the fuel economy should improve. My 2007 GTI turned 3k at 80 mph, I would've loved to have one more gear for cruising.
      Famsert
      • 1 Year Ago
      Also, I've got to say this is pretty embarrassing for those Ford fanboys (you know who I'm talking about) who were saying that all cars don't meet EPA estimates under normal driving conditions. Well it looks like the Accord can but the Fords CAN'T.
        Dean Hammond
        • 1 Year Ago
        @Famsert
        no, its REALLY embarrasing watching someone not read their comments, and consistantly cut and paste basically their same comment over and over...and THEN vote themselves up...pathetic actually, and hey, guess what, the Accord doesnt get its EPA estimated mileage at 110 mph....I smell something fishy....PFFFFFFFFFT....GO AWAY FAMSERT...you are one of the few that do Autoblog a dis-service by dumbing it down.............
        Dean Hammond
        • 1 Year Ago
        @Famsert
        ahhh, I see you here again under another pseudo....nice.
      Daniel
      • 1 Year Ago
      I have an old 95 Land Rover Discovery. Horrible on gas miles and usually get 15mpg cruising at 75mph. I once had to drive with a Land Rover Series IIa to an event and the little Series could only do 55mph, so I maintained that speed too. Ended up getting 20-21mpg! Great to see the difference but really we need to cruise at 75mph. Give modern day cars a nice overdrive or 6th/7th gear that brings the RPMs down to 1500-2k max.
      Famsert
      • 1 Year Ago
      "A couple interesting side notes in this tests include the four-cylinder Accord getting the same highway fuel economy at 55 mph as the Fusion Hybrid." You guys forgot to mention that CR also found that the Accord has BETTER highway mileage at 65 mph than the Ford Fusion Hybrid. Pretty sad on Ford's part... or pretty amazing on Honda's. Amusingly the Ford is rated at 47mpg highway and the Accord at 36mpg, meaning Ford's estimate is accurate only at 55mph whereas Honda's is accurate at 75 mph, which I imagine is how people normally drive on the open highway.
        Greg
        • 1 Year Ago
        @Famsert
        As a general rule, smaller engines will have a higher peak mpg, but it will occur at a lower speed. Since hybrids typically use a smaller engine supplemented by an electric motor, it makes a lot of sense that hydrids don't do better at higher speeds. However, a very important thing to remember is that the EPA hwy number does *not* represent your mileage when driving on an "open hwy." Rather, it is just a cycle that has higher speeds and fewer stops than the city cycle. But that being said, I really do think that Ford gamed the system with their latest hybrids.
          Famsert
          • 1 Year Ago
          @Greg
          My point is that the Accord can meet its EPA estimates under normal driving conditions (75 mph). The Fusion Hybrid can't. The others Fusions can't either (but at as bad as the Hybrid). The Accord smokes the regular Fusion in fuel economy and matches the Hybrid.
          Dean Hammond
          • 1 Year Ago
          @Greg
          do you want a gold star or another Accord poster for your ceiling?....
        karlInSanDiego
        • 1 Year Ago
        @Famsert
        Hybrids don't use the electric power at 55 or 65 (unless they are plug-in with a battery only mode) so it's expected that the Fusion Hybrid would not show any advantage at those speeds. I'm not a Ford fan, but it's silly to knock on a hybrid for not excelling at HWY when they're not designed to use their specialty drivetrain there. And reading EPA stickas will get you in heat because no one I know drives 55.
          chanonissan
          • 1 Year Ago
          @karlInSanDiego
          the nissan infiniti hybrid system does at 65 mph and hyundia up to 70 mph.
      RZ-Civic
      • 1 Year Ago
      Oh please! Fuel economy will not convince motorists to slow down. I usually drive 110 - 120 km/h on highways and still get close to the 52 MPG (Imperial) fuel economy rating.
        mikeybyte1
        • 1 Year Ago
        @RZ-Civic
        It would if gas cost what it does in Europe.
          tegdesign
          • 1 Year Ago
          @mikeybyte1
          No. It doesn't. When I lived there people didn't take much notice of fuel prices. People need to go where they need to go, and over there they drive much faster despite their fuel costs. Behavior control by price fixing is a scam to collect more taxes, and in the the case of fuel taxes, a very regressive tax at that.
      • 1 Year Ago
      [blocked]
      grizzy
      • 1 Year Ago
      Fuel economy be damned. 55 is just too slow and ridiculous to have as a speed limit. I lived in Europe for 4 months and gas is twice as expensive per gallon as it is here and people still go the equivalent of 80mph on highways. We're just spoiled and still live in the "American bubble". I'll continue to go 75-80 no matter what, and in my RS4, hyper miling is always an option.
      ngiotta
      • 1 Year Ago
      "Driving the extra 20 mph will knock about an hour off of a 200-mile highway drive, but the test shows that it will also burn an extra two gallons of gas." Hmmm. Save $8 or knock an hour off of the trip. That's a tough one.
        Julio B
        • 1 Year Ago
        @ngiotta
        "Calculated out for a 1,000-mile road trip, we see up to 10 gallons of gasoline could be wasted." Yet the article fails to mention that it could save 5 hours which could translate into an extra hotel night and extra roadside meals which would cost much more than the $40 spent on gas...
        Brian
        • 1 Year Ago
        @ngiotta
        Haha you beat me to it. It also makes it more tempting if you think about whose going to be in the car with you!
          m_2012
          • 1 Year Ago
          @Brian
          Its 4 hours, minus say 15 minutes for an extra pit stop. Are you getting paid to be in your car? How does saving time produce money? And dont give me "Time is money". No, its not. If it is, you are wasting your life away. If you get there sooner, where does this money come from exactly? A thousand mile road trip means: a) Personal vacation: Save money, drive slower. Decrease wear and tear on your car. Save more money in repairs. Better yet, take a plane. b) Business: I am getting paid to drive, so who cares how long it takes, within reason. Wrecking a company car will cost me much more. Saving them money on gas is a bonus. Better yet, take a plane. c) Who drives this far anyways? I have NEVER EVER made a 1000 mile trip in a car. That's silly. Take a plane. In the end, most trips are short and you speeding around traffic saves you no time and only costs you money in extra fuel and repairs. How many times do I see people speeding, only to be stopped with them at the next light or see them pulled over on the side of the highway. Now how much money did you save? I have never paid a speeding ticket either - I bet I could buy a lot more fuel with what people spend with those. Free money to people that did nothing for it.
          m_2012
          • 1 Year Ago
          @Brian
          Opps, wrong reply but still the same.
        Sean Conrad
        • 1 Year Ago
        @ngiotta
        Quite. When it meant an extra ~5 minutes on my commute to work but an extra 5mpg, I went the speed limit (in the right lane, thank you). When driving home from college and going faster meant getting there 45 minutes sooner but 5mpg less... I drove faster.
      IBx27
      • 1 Year Ago
      An hour saved costs two gallons of gas? Last I checked, my time is worth more than $10 an hour.
        • 1 Year Ago
        @IBx27
        [blocked]
          zoom_zoom_zoom
          • 1 Year Ago
          Excuses Excuses Excuses. Ford got caught just like Hyundai got caught
          merlot066
          • 1 Year Ago
          In tests with many driving conditions detailed and recorded, the C-Max, with an identical powertrain to the Fusion Hybrid, achieved 67 MPG in slow city driving. Also the point of the EcoBoost engines, and Ford's philosophy in general, is to increase mileage without going to extreme measures like dull, lifeless CVT transmissions. Ford is releasing 8 and 9 speed transmissions next year. Regardless, the 1.6 and hybrid powertrains in the Fusion had the lowest % mileage drop in the test.
          merlot066
          • 1 Year Ago
          @zoom, aaron, mary, whichever you're accidentally logged into when/if you reply The EPA has been investigating Ford's hybrid mileage claims for SEVEN months now and hasn't yet found anything wrong. Maybe they are still investigating and will reveal a huge lie on Ford's part. In the meantime, Ford hasn't been "caught" doing anything except breaking sales records one after another. http://www.autoblog.com/2012/12/10/epa-to-investigate-ford-c-max-fusion-fuel-economy/
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