Are high gas prices making folks slow down?

Is it just me or has anyone else noticed that people are driving a lot slower than they used to on the freeways? I’m all about doing the speed limit myself so I’m used to having people crawling up my ass most of the time—even though I’m in the slow lane—and only occasionally getting into the passing lane when I approach the rare person driving even slower than I am (often someone on their cell phone).

I’ve noticed over the past several weeks, roughly about the time gas hit four bucks a gallon here, a growing trend of people doing 65MPH or slower on the freeways. Whereas my excursions into the passing lane used to be infrequent and short lived they are now coming more often and for greater lengths of time. The number of idiots doing 90 while weaving through traffic has diminished quite a bit mainly because there’s too much congestion for them to have a hope of dodging their way through traffic.

It’s a simple fact that lower speeds use less gas, that was part of the motivation to make the speed limit 55MPH during the first energy crunch, but I’m surprised at the number of people who seem to be voluntarily participating in driving slower. At least one person I know says they’re definitely slowing down to save gas and has netted an extra 80 miles out of a full tank for doing so. It’s somewhat ironic that high gas prices are accomplishing something that draconian speed laws and occasional police crack downs haven’t been able to for years: Get people to drive slower.

Of course whereas I was once annoyed by people driving too fast I’m now annoyed by people driving too slow, but if I had to pick one of the two evils to deal with I’ll happily go with the latter one.

28 thoughts on “Are high gas prices making folks slow down?

  1. Michigan gas prices seem to vary from $3.95 to $4.29 per US Gallon

    To put it into perspective, here in the UK it costs me the equivalent of $8.91 for a US Gallon.

  2. Yeah, I’ve been doing the same thing. I used to drive 70-80 on the freeways, always kept my SHO right at about 2800-3000 revs or so.

    Now I’m quite satisfied to have it at about 1900-2200, which is where it revs between 50-65mph, and I’m impressed with the mileage I’m getting.

    I’ve also started accelerating more slowly from a stop, and I turn off the engine when I’m caught by a train or at a stoplight that I know I’m going to be at for a while.

    We all gotta do what we gotta do, right? Now I only wish I’d been doin’ it sooner. Oh well, you’re only stupid if you don’t learn from your fuckups, right? LOL!

  3. Trust me, I feel for you folks. Every time I even mention gas prices here there’s at least four comments from European SEB regulars about how lucky we are.

    You’ll note that I didn’t bother complaining about gas prices in this entry. I’ve learned my lesson about doing that. grin I’m just amused that the higher prices seem to be getting folks to slow down for a change.

  4. Well, at least most places in Europe have better public transportation. Everything here in the midwest is so far that it would take hours by bus, and scoots can’t go that far unless they’re the expensive maxiscoots.

  5. Yeah, if gas keeps going up then there’s finally a good argument for moving to one of those high crime, noisy neighbors, urban areas I try to avoid.

    Or Europe, which is probably nicer anyways.

  6. Les, you say

    It’s somewhat ironic that high gas prices are accomplishing something that draconian speed laws and occasional police crack downs haven’t been able to for years: Get people to drive slower.

    Speed limits, like all laws, are only effective if the threat of being caught, and the penalty for being caught, are perceived as being high enough to make breaking the law not worthwhile- or if the reasons behind the law (in the case of speed limits, safety and environmental concerns) are perceived as being worthwhile.  Obviously, many people would rather take their chances and speed.

    But economic considerations are enforced on all- you might not get caught driving 90 mph to work, but you won’t get away from paying for the gas. I suspect that the only way to get us living greener is to attempt to assess the burden on the planet of goods of the goods we consume, and factor that into the price, for instance in the form of a CO2 tax.  That would mean no more gratis externalization of the costs of environmental damage, such as the cost of the CO2 produced by gasoline, or those fruits imported from South America, or those plastic toys that are discarded in a week. Obviously not easy to do, but the alternative is going to be grim- if not for us, then for our children.

  7. Part of the appeal of moving to Ann Arbor is the availability of hybrid-biofuel powered mass transit there. If I find that I can lock up a bike properly in the apartment complex then I may break down and buy one for getting back and forth to work.

  8. Our old Fiat 124g used to get 35mpg at 75mph.  But cars got a lot heavier because of – pffft! – “safety” and now it’s hard to achieve those figures without a lot of “technology” ‘n stuff.

  9. In Los Angeles the opposite seems to be true – people are driving faster because there’s suddenly a significant drop in traffic. This occurred about when regular hit $4/gal.

  10. Michigan gas prices seem to vary from $3.95 to $4.29 per US Gallon

    To put it into perspective, here in the UK it costs me the equivalent of $8.91 for a US Gallon.

    We also get paid in US monopoly money.

    Our old Fiat 124g used to get 35mpg at 75mph.  But cars got a lot heavier because of – pffft! – “safety” and now it’s hard to achieve those figures without a lot of “technology” ‘n stuff.

    Weight mainly affects city fuel economy, not steady state cruising, which is mostly about drag and gearing.

  11. Weight mainly affects city fuel economy, not steady state cruising, which is mostly about drag and gearing.

    Except you need a bigger engine to give suitable acceleration in the city, with a heavier car.  Average engine power has about doubled since that Fiat was made. 

    Some big cars address this – I don’t know how – by shutting off half the cylinders at highway speed.  Clever, those engineers.

  12. Except you need a bigger engine to give suitable acceleration in the city, with a heavier car.  Average engine power has about doubled since that Fiat was made.

    Some big cars address this – I don’t know how – by shutting off half the cylinders at highway speed.  Clever, those engineers.

    Having a larger engine certainly leads to more pumping losses even while cruising (engines are generally most efficient at peak torque, and large engines don’t need to come anywhere near that most efficient point to do highway travel), but drag and gearing are still more important.

    Compare the 350hp 2002 Corvette my brother in law had to my 133hp 1997 Miata.  Both are manual transmission sports cars.  The Corvette has a 5.7L V8 to the Miata’s 1.8L I-4, and weighs 800lbs more than the Miata.  The Miata is EPA rated at 23/29mpg and the Corvette is rated at 19/28mpg.  Cruising at about 80mph, my Miata gets 30-31mpg, his Corvette got 33-34mpg. 

    The Corvette certainly didn’t have weight or low power in it’s favor, but what it did have is lower drag (hardtop, though the Corvette convertible is rated exactly the same, and very small frontal area), and a super tall 6th gear for highway cruising (top speed in 6th was actually lower than top speed in 5th for C5 Corvettes).

    Weight and power certainly came into play in Chicago traffic though.  The Corvette averaged 15mpg, my Miata averages 21mpg when driven exclusively in non-highway travel.

    Cylinder deactivation is a neat trick, the valves are closed on certain cylinders, trapping exhaust gasses, and fuel is cut to the deactivated cylinders.  Various engines with deactivation work differently.  Honda’s V6 shuts off one cylinder bank, Chrysler’s Hemi V8 skips every other cylinder in the firing order, GM’s current small block V8 shuts down 4 cylinders at a time, alternating side-to-side and front-to-back.  Of course, working better than Cadillac’s ill-fated V-8-6-4 is all that matters.

  13. I got 35mpg at 75 on a 5 hour drive this week in a 08 Honda Civic with the a/c on.  I average 29mpg in city driving during the winter, haven’t measured it with the a/c on yet.  My car sticker says the ranges are 20-30 city and 29-43 highway with the average being 25/36. 

    Best mpg, even though I couldn’t actually measure it: coasting down the mountains in New Mexico from Cloudcroft to Alamagordo on my motorcycle.  I didn’t want to kill the engine in case I needed the power, but I did kick it into neutral and let the grade maintain my speed(about 45-50 due to traffic).  I did the same coming back from Sunspot, but I had to ride my brakes on THAT slope.

  14. This is NOT happening in Dallas.  I went to The Store yesterday .. about 13 miles round trip.  As an experiment, I drove the speed limit.  Part of the trip involved using the North Dallas Tollway.  I was passed by hundreds of vehicles – many of them SUVs and F250 pickups.  Also spotted no less than three black Hummers, cruising along at 15 miles above the speed limit.

    It’s well known that speed enforcement in Dallas is a joke, anyway, but I did NOT see people slowing down to converse gas.

  15. It’s really no surprise that Texans aren’t playing by the same set of common sense as the rest of the nation, is it? Accepting Texas into the union was the worst mistake the country ever made in land acquisitions.

  16. Ragman, I’m dieing to buy me a new Honda Civic or even the Fit. They look like fun cars.

    NTB, my knee jerk reaction is to make a joke about Rich Texas Oil Men, but I have no idea if it’s even remotely true.

    Fact is that Michigan’s economy is the worst in the nation right now so it’s entirely possible the effect is heightened here.

  17. I was going to mention NTB’s observation about North Texas driving, but got distracted thinking about my mileage.  It ain’t happening here, they’re still hauling ass. 

    I really like my Civic, except for the acceleration.  I expected a little more going from a 124HP Saturn to a 140HP Civic.  That and the apparent miss on switching the console around the gearshift to left hand driver seating are the only real annoyances I’ve had so far.

    Rich Texas Oil Men

    No, not the ones hauling ass in SUVs and luxury cars.  Those tend to be more of the “Big hat, no cattle” as the saying goes.  Or the $30k millionaires.

  18. That is something I’ve encountered before – in an engine class I took in high school, we had to hook an engine up to a dyno and measure horsepower at different RPM.  Some engines produce maximum power only in a narrow range of RPM’s.  Others produced less peak power, but over a wider range. 

    That was back when the advance curve of a distributor was determined by manifold vacuum and centrifugal weights.

  19. It’s a simple fact that lower speeds use less gas

    I used to drive 70-80 on the freeways, always kept my SHO right at about 2800-3000 revs or so.  Now I’m quite satisfied to have it at about 1900-2200

    I’ve got a question that I hope someone here can answer. Does going slower really give you better mileage, and if so..why?

    I’ll change the numbers above, just a bit for my point: if your car is going 50, at 1500 RPM’s, and then when you go 75 you go to 2250 RPM’s it seems to me that it would be a wash. 50% faster, for 50% more RPM’s.

    Assuming that your car isn’t straining at the higher speeds, and ignoring wind resistance…is there some other factor that causes worse mileage at the higher speed?

  20. Ignoring wind resistance would result in little difference in mileage. Here’s why according to a CNN.com Money article from back in April:

    In a typical family sedan, every 10 miles per hour you drive over 60 is like the price of gasoline going up about 54 cents a gallon. That figure will be even higher for less fuel-efficient vehicles that go fewer miles on a gallon to start with.

    The reason is as clear as the air around you.

    When cruising on the highway, your car will be in its highest gear with the engine humming along at relatively low rpm’s. All your car needs to do is maintain its speed by overcoming the combined friction of its own moving parts, the tires on the road surface and, most of all, the air flowing around, over and under it.

    Pushing air around actually takes up about 40% of a car’s energy at highway speeds, according to Roger Clark, a fuel economy engineer for General Motors.

    Traveling faster makes the job even harder. More air builds up in front of the vehicle, and the low pressure “hole” trailing behind gets bigger, too. Together, these create an increasing suction that tends to pull back harder and harder the faster you drive. The increase is actually exponential, meaning wind resistance rises much more steeply between 70 and 80 mph than it does between 50 and 60.

    Every 10 mph faster reduces fuel economy by about 4 mpg, a figure that remains fairly constant regardless of vehicle size, Clark said. (It might seem that a larger vehicle, with more aerodynamic drag, would see more of an impact. But larger vehicles also tend to have larger, more powerful engines that can more easily cope with the added load.)

    That’s where that 54 cents a gallon estimate comes from. If a car gets 28 mpg at 65 mph, driving it at 75 would drop that to 24 mpg. Fuel costs over 100 miles, for example – estimated at $3.25 a gallon – would increase by $1.93, or the cost of an additional 0.6 gallons of gas. That would be like paying 54 cents a gallon more for each of the 3.6 gallons used at 65 mph. That per-gallon price difference remains constant over any distance.

    So it turns out that wind resistance has a lot to do with it.

  21. That suggests a car with really superior aerodynamics might devote a smaller percentage of its power to pushing air and pulling partial vacuum.

    I once had a Geo Metro XFI.  For a lightweight car, it wasn’t affected by crosswinds much.  A little silk slipper, that one.  MrsDoF made me sell it because it didn’t have air conditioning but damn it, the thing got 50+ on the highway!

  22. Miami Luxury Dumbass:
    I put acetone in my gasoline and it increases my mpg by about 25%. Works for me.

    25% claimed to be saved, 100% bullshit. If simple acetone actually worked it would be used in every tank of fuel. Especially in Europe where “Big Oil” isn’t controlling the car companies like the conspiracy nuts like to claim is happening in the USA.

  23. Just saw this thread again.  Aerodynamics are certainly important for fuel efficiency at high speeds.  My brother used to have a 1972 Saab Sonnett, which was low and light- I once picked up the rear end and moved it over to the lawn as a joke- got very good mileage (around 30 mpg combined), and would coast down even gentle freeway grades at 65 mph.

    Another celebrated streamlined car was Buckminster Fuller’s Dymaxion Car, which was also getting around 30 mpg in 1933!  It did have problems, however, and never got into production, but it was a brave experiment.

    I was once privileged to hear Fuller give a talk at a junior college- what an intellect the man had.  He held us spellbound for a good two hours, speaking without notes, and he must have been around ninety.

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