National Speed Limit to Help Save Gas? Not so Fast!

Remember the days of $4 gasoline?  Ah, they seem so long ago – even though it was less than three months ago.

Anyway, one of the many proposed ideas to help ease the pain at the pump and help drivers consume less gasoline was to implement a national speed limit, which would reduce the maximum allowable driving speed to top out at 55 miles per hour.

However, with all of the recent Federal intervention and meddling in an effort to revive the economy, one would imagine Congress has much bigger things to worry about.  Besides, do we really want the government to step in and impose even more regulations upon us?

According to a recent poll on, a vast majority of drivers are against a government mandated speed limit.

The poll asked the following – Should the government mandate a national 55 mph/90 kph speed limit to cut fuel consumption? Here’s how over 41,000 drivers responded:

  • 12% said Yes, because it would save fuel.
  • 5% said Yes, because it would make the roads safer.
  • 41% said No, because it’s too slow for today’s highways.
  • 9% said No, I support 55 mph, but not government involvement.
  • 29% said No, we should only enforce current limits.
  • 1% had no opinion

So, nearly seven out of ten drivers oppose this idea on some level.

The idea behind reducing the speed limit is pretty simple – the faster you drive, the more fuel your car is going to use in order to overcome increased aerodynamic drag.  In fact, for every five mph you drive over 60 mph, you end up reducing your fuel economy by roughly eight percent.  So there’s certainly some merit behind the idea.

Should the Federal Government follow through on this, it wouldn’t be the first time they have forced a reduction in the speed limit in order to help reduce fuel consumption.  Back during the oil crisis of the 1970s, the government reduced the maximum allowable speed limit to 55 mph, where it stayed until 1995.

However, with gas prices falling further with each passing day and Congress busy with the financial crisis, it’s looking less and less likely that this legislation will see the light of day.  And based on this poll, that might be the most favorable thing Congress has done in a long time.


  1. John Roberts says

    LOL, Reduce it? They need to INCREASE it or do like they do in Germany and have NO speed limit. What a croc!


  2. As usual, the posted information is wrong. In fact, the proposed speed limit would be 60 MPH, not 55. It is a wonder that web sites don’t post headlines like “Are you willing to put up with 40 MPH speed limits?” Then, somewhere buried in the article, it would say that the 40 MPH speed limit would be for traffic on 5th Avenue in Manhattan. That is how jaundiced and misleading the web sites are. And Drudge is the biggest offender. The media is not exempt from out and out lies too. Just listen to Sean Hannity for a few minutes and you will know what I am talking about.

  3. Hell no! Why should I have to throttle back my compact because some a-hole in a Hummer or other gas guzzler get’s low mileage. I say set the speed limit to 3X the EPA rating then I could drive 90+ while the gas hogs would have to drive under 50!

  4. DynamicRes says

    maybe this is just my car, but i get way better gas millage going 75 than going 55. a difference between around 30mpg and 26 mpg.

  5. the sad part is looking at the phrase below and considering the majority of those dont even have the skills to drive 80mph and above on the hwy all while either doing makeup, texting, or chatting away on the phone.

    “41% said No, because it’s too slow for today’s highways. “

  6. Eight Percent says

    The 8% savings that you suggest is ridiculously optimistic. In fact it is utter rubbish. Try it for a week. Slow your highway driving from 70 to 60 MPH. I guarantee that your mileage will not increase by 16%. If only it were that easy.

    The 8% may have been possible in 1975 but, today’s vehicles are sufficiently efficient that you will notice little or no difference in mileage whether you drive 55 or 70MPH.

  7. This 55 MPH speed limit would NOT save gas, cars of today have much more sophisticated transmissions equipped with overdrive that make cars most efficient around 80 MPH, this coming from an owner of a 6 speed 1994 Z28 Camaro with a 383 stroker motor (450HP) I get 28MPG highway cruising at 80MPH @ 1,800 RPMS

  8. So according to a poll done on a website that not many people have heard of and that must have a margin of error in at least the 10% range, here’s how Congress should write policy!

  9. No one seems to remember that the federal government has no authority to set speed limits in the many states that make up our union. That should be the end of the idea and its discussion right there.

    But, even if they did, there is more to consider than fuel economy. Slower speed limits equal more time traveling. Most citizens value their time; many more so than the difference in cost for mileage savings. Since you are allowed to drive 55 on motorway even if faster is allowed, then it makes sense to leave things be. Those who are in a hurry can spend more money on gas but use less time, those who aren’t can choose to drive 55.

  10. I have a ‘huge gas guzzler’ that some of you refer to. I use the truck for work many weeks of the year so I can’t really get anything smaller.

    My Dodge diesel gets 20 MPG at 70 MPH (which I am thrilled about because of it’s size and wight). When I drop my speed to 60 MPH, I get 26 MPG which is a 30% increase. If I drop all the way down to 55 MPH, I get over 30 MPG which is a 50% mileage increase.

    I agree that many small cars that most of the country drives may not see a large improvement but anyone who has a vehicle with a high amount of wind resistance (Trucks, SUV, SEMI’s) will definitely see an increase in mileage.

  11. I have an Mercedes SLK350 & at 55 to 60 I’d be lugging the engine in 6th so I’d have to drive in forth or fifth where I get crappy gas mileage. I get around 22 MPG in that range. At 75 to 80 I get 29 MPG. With modern advances in areodynamics it’s now all about the RPMs stupid.

  12. Even with older cars the difference is not that dramatic between 55 and 70. It depends a lot on the gearing. In my 1965 chevy 1/2 pickup (before I modified it) I used to get about 13Mpg just about everywhere – and on the highway at 70, that would drop to about 11Mpg. Today, among other changes, that truck has a much higher geared rear end and gets about 19Mpg normally and about 17Mpg at 70Mph on the highway. My unmodified 1987 Firebird actually gets better gas mileage at 70 than it does 55 because of how the gearing on it works, with it’s overdrive (as most cars and trucks have today) it gets about 22Mpg at 70, and about 20Mpg at 55.

    Also, I don’t know where you live, but here in Missouri – highway speeds have never been limited to 55 that I can remember. They were 65 up until about 93 or 94, and then went to 70. I guess it could have been 95 when the speed limit changed (as you state in this article) – but the fact remains, the limit was never 55Mph (at least as far back as I can remember going back to about 1980) – it was 65.

  13. what-matters says

    Speed and the use of gasoline..

    How much gas do you use? can you tell when the car is using the most gas?

    It’s about your RPM’s (revolutions per minute)
    If your car goes 55mph in 4th gear at 3000rpm, yet you can do 80mph in the 5th at 3300rpms, it’ cheaper to go 80mph.

    So with this simple example you can draw your conclusion.

  14. Slow down here! Driving slower would increase congestion (and use more gas) in urban/suburban areas, where most of the gas is used! This yet another proof that statistics don’t lie, but liars use statistics.

  15. Eric got close to the subject, but GasBuddy is not a ‘lesser-known’ site. It’s quite popular among those that are trying to save cents on the gallon of gas. Does no one think that GasBuddy visitors a tad biased in such a poll?

  16. Fuel economy at a given speed is determined by engine tuning. Since cars sold in America are tuned for American driving habits, they get poorer performance at speeds above 45 MPH or so. Interestingly, many cars start to again improve in fuel economy around 75-80 MPH. Why don’t we raise the speed limit please?

  17. 11, 13, 20, 22/mpg –
    GET A freaking REAL car
    ’94 Sentra 4 door – 45/mpg (commuting)
    closes on 50/mpg on long highway trips

    the only modification from stock is 14″ wheels, and HP rated tires.

    oh, and btw – it DOES NOT have an overdrive (and neither do most manual transmissions)

    as for a national speed limit —
    this has one major problem — States rights, as mentioned in the Constitution… Those rights NOT EXPLICITLY given to the Federal Gov’t are reserved to the People or the States.

    the national speed limit was implemented/enforced previously – illegally – by the threat/action of with holding Federal subsidies for Highways and bridges for those states which refused to post and enforce the 55mph speed limit. Montana was one of 2 or 3 states that refused to accept the limit and did without Federal highway funds.

    I think (from memory) that the list was Montana, Nevada, and Missouri (but I could be wrong on this).

  18. The government does need to intervene…and make all interstates 75mph to ordinary vehicles, 60 for 6+ ton vehicles. I can make it 325 miles on a full tank of gas (11 gallons) if I drive around 80…I just did it twice last week. There was even road construction where I had to come to a complete stop and wait for 5 minutes.

    If they imposed the speed limit of 55, I’d be spending more money in tickets than I am in gas right now. But maybe that is there plan…does the government really care about gas savings? How about all the senators and congress take the bus to their jobs then? How about we get out of Iraq and quit spending gas going back and forth to the middle east with planes and such? Seriously, they don’t care about gas, they care about trying to get more ticket revenue if anything.

  19. I’ve been driving at 55mph for many years. What I have found is that when I get to work or the store I am more calm and relaxed. My gas mileage is 20mpg for an F-150. I stay to the right lane and let others go around and I enjoy an empty lane ahead of me. I have a bumper sticker whwich says ‘ Drive 55 and bring a Soldier Home ‘.
    55 mph, I’m all for it!

    Maxxer, lakewood,ohio

  20. It is physics (drag coefficient, and parasitic loss are the major players). The slower you drive the better your mileage will be. Now saying that all vehicles will improve 8% for every 5mph slower they drive is not a fair assumption. Also implying that the 8% is cumulative is also not correct. After all you will reach a point of diminished returns. If the 8% is cumulative then you should be able to drive slowly enough to have the tank fill itself 😉 I suspect that properly filled tires, or even tires filled to their posted maximum would have the same effect. If you don’t believe this is true, go push your car on level ground at a walking pace. Then try pushing it at a jog. Does it take more energy? Try it again with underinflated tires… you get the idea.

  21. Do away with speed limits, except for SUVs and trucks. Give ’em enormous fines for running the tanks and twitmobiles on the highway, unless they’re hauling cargo.

  22. dunno about you guys but uh…. I get better mileage at 75 than 55.

  23. You can’t argue with the laws of physics. Above 30mph the amount of energy the car uses pushing air aside is greater than the amount it uses overcoming rolling friction. The resistance curve rises quite swiftly after 55mph, going up 1% for every additional mph.

    So for a one hour trip going 75 is going to cost you 20% more while getting you there only about 20 minutes faster. That does not take into account the greater wear on your car and the reduced time you have to react to a crisis at 75mph.

    You can see the figures here:

    One thing that is not often considered is that fuel prices change according to demand, so if everyone were driving 55 the demand for gas would be 20% less and so the price would likely follow that decrease as well as making us less dependent on foreign oil and a little richer.

  24. seriously limiting anything as trivial as this is bound to backfire. I personally think speed limits in general are plain ridiculous.

  25. Tom Galloway says

    Um, didn’t they learn the first time around? Sammy Hagar said it right the first time: we can’t drive 55!

    If Congress wants to ease the pain at the pump, then tell the oil barons to either increase production and drop prices, or go to jail with the rest of the rapists, muggers, thieves, murderers and child molesters.

  26. Chuq Von Rospach says

    “One thing that is not often considered is that fuel prices change according to demand, so if everyone were driving 55 the demand for gas would be 20% less and so the price would likely follow that decrease as well as making us less dependent on foreign oil and a little richer.”

    This is horse-hockey. When it was implemented in the 70’s, prices continued to go up and never dropped back down to what gas should still be – 25 cents a gallon. The lower demand=lower prices claim has been debunked for over three decades now, and anyone trying to foist it still is just shilling for the oil companies.

  27. Chuq Von Rospach says

    “I think (from memory) that the list was Montana, Nevada, and Missouri (but I could be wrong on this).”

    Montana, Wyoming and Nevada. Missouri *tried*, but wound up backing down because they needed the funds.

  28. Wow. Reading the replies to this post leaves me feeling hopeless. The degree of misunderstanding of basic scientific principles is stunning. One reply said “It’s about your RPM’s (revolutions per minute)
    If your car goes 55mph in 4th gear at 3000rpm, yet you can do 80mph in the 5th at 3300rpms, it’ cheaper to go 80mph.” Amazing.

    As for the limit itself, Congress didn’t pass a law making a nationwide speed limit of 55 m.p.h. Instead, they passed a law requiring states to implement a 55 m.p.h. speed limit in order to receive any federal highway funds. States could choose to forgo such funds and set speeds however they wanted. Needless to say, most, if not all, states chose to keep receiving the funds. Thus, speed limits were 55 m.p.h. nationwide, but there was no national speed limit.

    As for those who “get better mileage at 75 than at 55,” this is not impossible but it’s very unlikely. The vehicle is encountering slightly less than twice as much drag force at 75 as at 55. Aerodynamic drag is about 75% of the resisting force on the car at that speed (the remaining 25% is tire rolling resistance), so it would be a pretty unusual engine map and gearing combination that would enable the engine to be sufficiently more efficient to overcome the increase in drag for a net gain in fuel economy.

    In short, I doubt it.

  29. Forget SAVING money, just give ME a part of that 700 BILLION dollar package!!!!

  30. if your talking about mileage you can increase it by just upgrading your car into hydro cars, its not only the benefit, it also reduces fuel consumption and pollution too, there are sites that offers services on converting your car, its not complicated. try to think about it.

  31. My 1994 Ford Escort LX Wagon, gets about 28-30 mpg when driving normally, the freeway occasionally 70-90mph (depends how badly I feel like speeding), highway every day at 50-55 mph, and through town every day at 20-30 mph. But when I have the need to drive to Seattle, I’m on the freeway going about 80 mph the whole way there, and when I check my mpg it jumps all the way up to 38 mpg. Therefore, I def don’t want a 55 mph speed limit. Yay for speed.

  32. First of all; gas mileage is related to engine speed+load, not necessarily the car’s speed. there are actually cars that get better mileage @ 65mph than at 55.

    Secondly, 55 is way too slow for today’s cars and roads. If anything the speed limit needs to be raised!

  33. MrBoJangles says

    These statistics are completly wrong! I have an 84 camaro which gets its best gas mileage around 88 mph. I also have a chevy 3500 van which gets its best gas mileage around 45 mph. So its completely dependent on the individual car

  34. Paul Strauss says

    “Nearly 7 out of 10 oppose this on some level”…problems with the math. It’s actually more than 7 out of 10 oppose this– actual number is 79% opposed:

    41% said No, because it’s too slow for today’s highways + 9% said No, I support 55 mph, but not government involvement + 29% said No, we should only enforce current limits = 79% say NO.

    This is just one more attempt by proponents of the nanny-State to control every aspect of our lives. It is an exercise in compliance with the unreasonable, and unjust enforcement so that when it comes to incrementally more intrusive and unjust laws we’ve already rehearsed compliance– because we’re already used to obeying. OBEY, OBEY, OBEY you cannot choose for yourself a safe and reasonable speed is the underlying presupposition.

    It’s WRONG- it’s wrong that 55 saves lives- it doesn’t. 55 doesn’t save gas, either. Double nickel was a failure of big government on every level.

    The flip-side of people obeying every stupid law are laws so stupid nearly everyone disobeys– the first time around compliance with 55 mph was OPTIMISTICALLY estimated at 2%.

    The problem with that is that it breeds contempt for ALL laws, thus undermining the rule of law and weakening social order.

    In short- if you research it intelligently with an open mind and look carefully at the actual RESULTS of the failed experiment with 55 mph speed limits and IGNORE the claims of what it will do– you’ll find it is a terrible idea.

  35. Paul:

    If you object to lowering the speed limit to 55 m.p.h. on philosophical grounds, i.e., that people should be able to choose to go faster and get worse mileage if they’re willing to pay for the fuel, you have every right to hold that position.

    But to contend the that 55 m.p.h. won’t save gas is either ignorant or disingenuous. Every reputable study by agencies both public and private that I’ve read (and I’ve read every one I could find) states the opposite. Common sense and the laws of physics deem the opposite. I can direct you to literally dozens of studies to show that if you like. I can walk you through the very simple physics if you would care to have me do that. Your wishing and stating with conviction that it won’t save gas won’t make it so.

  36. Paul Strauss says

    “But to contend the that 55 m.p.h. won’t save gas is either ignorant or disingenuous”

    I never intended to contended that driving 55 mph wouldn’t save gasoline. I was referring to the law when I wrote, “It’s WRONG- it’s wrong that 55 saves lives- it doesn’t. 55 doesn’t save gas, either. Double nickel was a failure of big government on every level.”

    Changing the law did not then, and will not now save lives or gasoline– because it was, is, and will continue to be one of the most universally ignored laws ever passed.

    To deny that is well…what you said. 🙂

  37. That may be what what you meant, but what you said was “55 doesn’t save gas either.” You may be knowledgeable enough to know that, for the vast majority of passenger vehicles, 55 m.p.h. will save gasoline compared to, say, 65 or 70 m.p.h. But there is a huge contingent out there who contends that “it’s all gearing – my SuperBeaucoupGoquick 9000 gets better gas mileage at 85.” Some of them say it in the comments to this post.

    I’ve not seen any studies (though I’m sure they exist) on whether 55 m.p.h. saved lives so other than to point out that a vehicle going 65 m.p.h. has 40% more kinetic energy that that same vehicle has at 55 m.p.h. and that that energy gets turned into bent metal in a crash, I’ll remain silent.

  38. 79Camaro327 says

    I don’t know about you guys, but the college I go to is 220 miles away from home. So it takes me 3 hours to get from school to my home town. If the speed limits were lessened to 55, it would take 4 hours. I personally don’t care how much gas it takes, I don’t want to drive 55 on the highway. The minimum speed posted on most interstates is 40mph, so if you want to go slow that’s your choice, but why ruin it for the rest of us?

    I also think gas mileage has a lot to do with gearing, because at 75-80 mph my Z28 turns about 2300-2500 rpm, which is where the engine is most efficient (able to make the most power with the least amount of fuel).

    Another thing… I think I’m speaking for all the other gearheads out there- It doesn’t matter how much gas costs. I am still gonna drive my hotrod. My other camaro gets about 6mpg, runs on $8/gal LEADED gas, no overdrive, 4.11’s… and I would still drive it if gas was $50 a gallon

  39. I’d say absolutely yes. The speed limits need to be lowered and strictly enforced with stiff fines. If nothing else the current limits should be strictly enforced. Speeding is the root cause of most problems on the highway. Speeders also tend to tailgate, change lanes without signaling, run stop signs/lights and drive too fast in parking lots, school zones and residential neighborhoods. Not only would reduced speed lower fuel consumtion and pollution, it would save lives and property damage caused by the accidents speeding creates. I’m tired of hearing the moronic responses of adolescent minded jerks who speed mainly because it makes them feel some kind of power. Maybe if they had the power in their pants they wouldn’t feel the need. Also ban motorsports!


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