The MARKET will decide how fast we drive or IF we drive…A posted 55mph speed limit on roads designed for 75mph just turns the cops into revenue agents. After you get 4 or 5 speeding tickets, your insurance goes from $300 to $1300 a year, so basically, a 55mph speed limit is a GIFT to the auto insurance industry, provided by the speed cops…
I was 21 years old and I was riding a two-stroke motorcycle that didn’t even want to be in fifth gear at 55. It wasn’t like I was late for church.
Wind resistance increases as the SQUARE of the speed, while rolling resistance is more linear. Where this starts taking effect depends on the shape of the car, or the coefficient of drag.
Most cars up to 50 mph do not suffer any significant loss of economy due to wind resistance increase. That’s maybe why the 55mph limit was chosen. In the mid seventies US cars were square boxes compared to the present ones.
Modern cars with overdrives and slick shapes should not lose too much fuel economy under 60 mph, I would guess.
But, as mentioned previously, a VW TDI at 80 mph uses a lot less fuel than a V8 SUV at 55.
Just to be picky, the force required to overcome “wind resistance” increases with the square of speed while the power required increases with the cube of speed. I agree that the design of the car is much more relevant than any arbitrary speed limit.
I agree in urban areas it will work, but on the highway its just gonna put more money in the State coffers
because of the volume of speeding tickets. It’s true people are going to speed anyway but if your driving
from NY to GA do you want to spend longer hours driving in the dark and possibly an extra day in a hotel?
Or do you want to get from point A to point B as quick as possible? I tried it in the 70’s and it took 4-ever to get from Florida to New York do the math and see how much time you gain 70 vs 55. And as far as oil prices go how fast or what we drive didn’t make a difference then and it won’t now.
I agree. In fact earlier this week I sent the following letter to my representatives in Congress, the governor of Oklahoma, and a couple of newspapers. It reads:
" In the 1970s, I was in my twenties, living and working in Oklahoma City and driving a VW Beetle. There was an energy crisis. In 1973 President Nixon signed the Emergency Petroleum Allocation plan which regulated gasoline and home heating fuel prices. At one point, there was even gasoline rationing. For a time, because my car tag ended in an even number, I could only buy gasoline on a calendar day that was even. I realize we live in different times now; however, there is something we can do as a state and as a nation that was done in the 1970s: set a national speed limit. The Emergency Highway Energy Conservation Act, signed on 2 Jan 1974, established a national 55 miles per hour speed limit to reduce gasoline consumption; ridesharing was encouraged also. This Act slowed the consumption of oil; brought down the price of oil per barrel and built up the United States? supplies; reduced automobile accidents; and, perhaps most importantly, it gave the American people a feeling of control over our lives. We knew that by driving slower we were performing an active patriotic act. We were doing it for the collective good of the citizens of this country.
Some may argue that in this free market society, an individual is free to choose whatever sized vehicle he or she wishes to drive – I will not get into the fact that the gigantic SUVs that roam our highways should have never been allowed to have been built in the first place ? as rapidly down the road as he or she wishes to drive, and pay whatever price a gallon of gasoline he or she can pay. However, I argue that as a nation, we are all in this together, and if we all drive slower, we can build up the oil reserve, reducing the need for gasoline, thus reducing the price.
What a difference 2008 is from the 1970s. Today we whine and cry about the price of oil going up; the media even makes it sound exciting when a barrel of oil reaches a new dollar amount while we feel impotent, unable to do anything but open our wallets and pay more and more for a gallon of gasoline. Not everyone has the income to buy hybrid cars. I applaud those that have purchased more gas efficient cars. Most of us, though, have to make do with the vehicles that we have.
Maybe I?m being na?ve, but wouldn?t a national drive 55 campaign help unite the country in a common cause that would benefit all Americans? What pain would it cause Americans to drive 55 mph? Why haven?t any of our politicians mentioned passing a law that American citizens should drive 55 mph on the nation?s highways? We are in a national crisis. I am sure those 55 mph speed limit signs from the 1970s are stored somewhere."
I would encourage you to drive more slowly if you have some extra time on your hands. If that results in reduced fuel prices, I will pay less while I drive at more reasonable speeds. Obviously, a reduced “national speed limit” has no chance of happening, but we do appreciate your time and effort.
'I will not get into the fact that the gigantic SUVs that roam our highways should have never been allowed to have been built in the first place ’
ALLOWED ? By who ?
National Crisis ? Oh , yea the sky is falling ! I forgot !
The price of gas ? About where it should be accounting for inflation in the last sixty years !
Take what you want AND PAY FOR IT !
Sounds good to me, as long as motorcycles and small cars are exempt. Let’s let 55 apply only to SUV’s. That way the people who drive motorcycles and small cars will be happy and so will the SUV owners who, as we all know, only choose these vehicles for the safety that they provide. Surely, they will gladly compound the safety of these vehicles by only going 55.
There are many ways we can save fuel. Sure, a 55 mph is one - that impacts those of us who have to travel long distances on the open road. How much gas be saved? What about better traffic engineering in the cities? How much gas is waste and smog/CO2 released as gas sit in huge traffic jams day in and day out.
Or we could simply ban commuting to the city in your car (or make it much more expensive - say $25/day). Nearly all major cities have mass transit systems that could go from fair to good or even great. Sure mass transit is seedy and many of us look down on it as something that ‘they’ (meaning the less fortunate than us) use.
In the end, driving will be reduced and less gas will be used as each individual finds alternatives that fits their lifestyle. So let’s increase taxes and fund mass transit - only partially teasing about that.
Great ideas…but the difference in cost of implementation is great. I hate having to travel 55 mph on a limited access highway. I hate also pouring money into OPEC. Argue if we must that Mexico and Canada are our top importers. That’s just for conveinience on the world market pipeline. Remenber that very close behind is Venezuala and SA ( both opec ) whose import distance is much greater. The has to be as big an influence on oil futures in general to reduce cost. Canada is not going to sell us oil for less than OPEC just cause we are nice guys.
Still feel that 55 mph is the most effective (psychologically as well as actual demand) short term. Less than 5 year committment would , I feel, help turn things around. 55 mph gas/diesel, 65 mph electrics, buses, other mass trans and motorcycles on highways. Dig out the Harley.
I’d be happy with more drivers just maintaining 65 mph. I’ve tried to slow down to conserve but big trucks and larger SUVs bombing by me at 75/80 are just too scary in my little car.
I have seen a lot of people voluntarily driving slower to save money lately. You don’t have to do anything as extreme as driving 55 on the freeway, going 65 instead of 70 makes a significant difference. Going 70 instead of 75~80 also makes a significant difference.
Let’s keep our speed limits as they are and let gas prices be what they need to be. $3+/gallon gas has done more to spur conservation than any government coercion ever has.
Let’s get over the idea that the government owes us cheap gas.
You love your MPG slow down,
The big problem with letting people drive at whatever speed they please is that it is a hazard to have a wide range of speeds on a highway. All traffic should be moving at close to the same speed. If I want to drive 55 in the right lane to save gas, and you want to drive 80 in the left to get someplace in a hurry, the speed difference is dangerous. And let’s not even talk about the idiots doing 55 in the left lane and the leadfoots passing on the right at 80…
I strongly dissagree with the entire principle of slowing traffic down! Other than altering our roads to favor the insurance companies.Slow roads carry less cars in the same time .Slow roads are inherently congested.Slow roads create conjestion which by recent evidence increases wear and auto emissions fouling our air… All that slow roads do create is distracted,sleepy drivers filled with rage.
I win.
Hmm. And what kind of mileage would you have gotten if you had driven 65-70? 55-60?
Fuel consumption has to go up with increased speed (actually, with the square of the speed) due to aerodynamic drag. Road and drivetrain friction go up linearly with speed, but you’re driving for a shorter time (for a given distance), so it’s a wash. Non-speed related loads (electrical, AC) are constant, so you save by going faster and getting there sooner. Drag is the biggest factor, so slowing down does save gas.
(I wish this forum allowed tables)
low speed (V)
time taken to drive D miles: D/V = t
mechanical friction rate: aV
total energy to overcome friction: aVD/V = aD
aerodynamic drag rate: bV2
total energy to overcome drag: bV2D/V = bVD
A/C & other constant load rate: c
total energy for A/C etc.: cD/V
grand total energy (fuel): aD + bVD + cD/V = D(a + bV + c/V)
fuel per mile: a + bV + c/V
high speed (2V)
time taken to drive D miles: D/2V = 1/2 t
mechanical friction rate: a2V
total energy to overcome friction: 2aVD/2V = aD
aerodynamic drag rate: b4V2
total energy to overcome drag: b4V2D/2V = 2bVD
A/C & other constant load rate: c
total energy for A/C etc.: cD/2V
grand total energy (fuel): aD + 2bVD + cD/2V = D(a + 2bV + c/2V)
fuel per mile: a + 2bV + c/2V
For most vehicles, “b” (essentially the coefficient of drag) is the biggest factor and “c” is probably the smallest. “b” (C-sub-d) can vary slightly with speed (e.g., a “bubble” of stagnant air trapped in a pickup’s bed smoothing the air flow), but is usually fairly constant. It’s possible that driving slower on a very hot day (high A/C load “c” on a small engine) might lead to a slight increase in fuel consumption in a very slick car (small “b”), but I don’t know if it’s been demonstrated to be significant in real life cases.
P.S. Your time (t) is worth something too. That has to be factored in.
I mention that a speed of 80 mph will allow roughly 80/55X100% or 45.5% more traffic to pass a certain point than a 55mph limit.
Don’t forget that at the higher speed, traffic needs to be spaced out further for safety, reducing the capacity. Ah yes, the days of commuting on the Saw Mill River Parkway – 70 mph bumper to bumper.
That’s maybe why the 55mph limit was chosen.
The argument went: trucks do best at 50, cars do best at 60, let’s split the difference… thus the double-nickel was born!
B.L.E. The best compromise yet…strickly inforce the speed limits we have would go along way. In Europe you may get your speeding tickets in the mail with camera overpass monitoring. That would slow traffic down significantly…
I disagree that slow roads create congestion…it’s the variable speeds. If everyone did a better job of maintaining consistant speed, if it were 65 or 55, traffic would be less congested…merging is much easier, on off ramps safer and less congested as well.
Strict enforcement of speed limits is a good idea if the limits are reasonable. If the west, many of the interstates have 75 mph limits which aren’t really being enforced (average speeds are closer to 80-85). I normally drive at 75-80 on those roads, which is pretty reasonable for the roads and the traffic. Limits of 55 or 65 on urban highways is probably reasonable and should actually be enforced.
However, some eastern states currently have very low limits which are completely ignored. For example, much of NY has a 55 limit which is a joke. If you actually tried to drive 55 on most of the NY highways/parkways you would be run over. If those limits were increased to a more realistic value and enforced there might be less variation of speed on those roads. As it is, speed limits are pretty much irrelevant.