Monday, July 07, 2008
Gasoline prices and behavior modification
A couple of years ago, when gasoline was closing in on $3 per gallon, I argued that however much gasoline had risen in price up to that point, it remained a great value. My point was that ordinary Americans were not incurring even the most trivial inconvenience in order to conserve. I was not talking about anything that required a major new decision, such as moving one's house, changing one's job, or getting a more efficient car. At $3 per gallon, people were not even driving more slowly or, nearly as I could tell looking at my own company, carpooling, both of which conservation measures involve the substitution of a small amount of time or inconvenience for gasoline.
Over the weekend, I wondered if this was still true with gasoline well over $4. When I pulled on to the New Jersey Turnpike I set my cruise control at 66 mph (substantially faster than I would drive -- 55 or so -- if I wanted to maximize my fuel economy), got in the right lane, and started counting cars that passed me. I was passed by more than 40 cars before I came up behind another vehicle going more slowly than me, and it was a step van trying to exit. I gave up counting when more than 100 cars passed me without me passing anybody. At 66 miles per hour.
Now, I had always assumed that anybody who lived through the 1970s -- remember "Fast is Fuelish"? -- knows that driving more slowly saves gasoline. For people without a lot of disposable income (a group that includes, presumably, many of the people on the New Jersey Turnpike), the savings from slowing down can be considerable:
How much you stand to save depends on a lot of factors. With gas at $4 a gallon, a driver with a long commute - 400 miles a week - and a gas-guzzling vehicle getting only 20 mpg would save $18.74 a week by slowing down dramatically from 75 to 55 mph, extrapolating from the government's most recent figures on the subject. Even a more moderate deceleration - from 70 to 60 mph - would save that driver $11.74 a week.
The question is, why are people not slowing down? Is it that they are ignorant of the financial savings they could achieve, or is it that they know but do not care? If the former (which is very hard to believe), then the solution is to roll out some public service announcements. All those AGW activists out there should start small, reminding the average American that, well, fast is fuelish. I would not even object to some old fashion jaw-boning from the government if it would spread the news.
In any case, the fact that people are not slowing down notwithstanding gasoline over $4 is irritating the nanny-staters, who are talking about reviving the dreaded "double nickel." That strikes me as asinine. Even the Europeans do not require such slow speeds over their trivial intercity distances. If Americans, in the full knowledge of opportunities to save gasoline by driving more slowly, choose not to, it must be that gasoline remains, gripes notwithstanding, a good value. No longer an amazing farookin' value, but a good enough value that most middle-class Americans remain unwilling to trade either time or the presence of a co-worker for the money they would save.
32 Comments:
By 
MarkCh, at
Mon Jul 07, 10:07:00 AM:
A person with a 400 mile weekly commute would lose 2 hours a week by slowing down from 70 to 55 mph. If they saved $18.74 in gas, they would break even if they earned $9.50 or less after taxes. That would only include a small fraction of workers on the New Jersey turnpike. So, as you say, gas is still good value.
By 
, at
Mon Jul 07, 10:25:00 AM:
The question is, why are people not slowing down? Is it that they are ignorant of the financial savings they could achieve, or is it that they know but do not care?
They're waiting for the financial savings they'll realize from McCain's gas tax holiday. LOL.
By , at
Mon Jul 07, 12:42:00 PM:
I clearly recall the oil price shocks of the '70s. As a matter or fact my family and I drove to the east coast in May of 1979 because I had been reassigned to RAF Mildenhall, in the UK. There was gasoline rationing and high prices (relatively speaking), but it didn't seem to affect the driving habits of anyone on the Beltway or on the trip up to McGuire AFB in New Jersey.
Look for a return to that lunacy if Obamessiah gets the Oval Office. The voters in this election cycle seem almost gullible enough to replicate the election results of 1976.
By , at
Mon Jul 07, 02:55:00 PM:
Well, the average commute is more typically a third of your 400 miles, and many cars are getting 25 mpg and upwards on highways. The savings is probably far less than you suppose...which is why so many were passing you.
By clint, at
Mon Jul 07, 03:10:00 PM:
MarkCh nailed it in one.
How much would you pay to chop an hour off your commute? How much would you pay for an extra hour a week doing something you love, rather than sitting in traffic? (Does this sound a bit like an infomercial?)
A great many people choose to pay hundreds of thousands of dollars in increased housing prices to chop an hour off their daily commute.
Exactly how irrational are those same consumers being by saying "No, thanks!" to an offer to add an extra hour to their weekly commute in exchange for a crisp $10-bill?
By Georg Felis, at
Mon Jul 07, 03:12:00 PM:
Or phrased in Lawyer: How many Billable Hours would you forgo in order to save $18.74?
By , at
Mon Jul 07, 04:05:00 PM:
Given the average wage in NJ, I'd have to say that saving $20 a week is trivial, not considerable.
By Miss Ladybug, at
Mon Jul 07, 08:12:00 PM:
I have to agree with the "time is money" commentary. Most of my driving, unless I'm heading to a baseball game, is surface streets, so the whole "slowing down" thing doesn't really affect me. However, when I am on the freeway, I don't drive 55. For the small amount I would save per trip, it's not worth the added time. I have, however, changed my driving habits over the previous 3 summers (since I returned to Texas) - previous summers, I hardly missed a baseball game for our local minor league team. This year, I've limited it to weekend games - at a 70-mile round trip, doing that 8 days running is just too expensive given my other financial obligations. My sister, however, who doesn't have the same financial obligations (she's much younger than me), she is still going every day there's a game...
By , at
Tue Jul 08, 12:41:00 AM:
My work truck eight months out of the year is a 2002 Honda GL1800, basically a Civic on two wheels. You can get away with that in Colorado. It only gets about 37 miles per gallon, but it gets about 37 miles per gallon at a hundred miles an hour, which is kind of cool. It is a really big freaking country out here. I wonder sometimes if they realize that, back in DC.
By TigerHawk, at
Tue Jul 08, 06:40:00 AM:
The verdict of the commenters are clear! Virtually nobody is willing to substitute their time for the money they would save slowing down, and several have offered very cogent economic reasons why they would not. It is a little indication of the enormous cost to the economy and to our personal freedom imposed by the government actually mandating a 55 mph speed limit.
By JammieWearingFool, at
Tue Jul 08, 08:57:00 AM:
I live and work in NJ and drive around 500 miles per week. If you think folks are going fast on the Turnpike, try Route 287, where the average if 75-80 MPH. My experience is people want to get to work/home as quickly as possible to avoid traffic, which can be brutal after 8 am. During the summer I work early and actually drive a bit slower since there are fewer vehicles on the road at 6 am and I'd be an easy mark for the police if I were doing my usual 80.
Time is money and that's especially true with truckers; it's rare I see them doing anything less than 65-70.
From my vantage point, if you were to do 55 on 287, you'd be risking life and limb.
By Matthew Hooper, at
Tue Jul 08, 09:06:00 AM:
I feel like it's less a matter of doing the cost/benefit analysis on speed an more a matter of raw peer pressure - and safety. Go 55, or even the posted speed limit, on a major highway and it feel like you're taking your life into your hands. The truckers will barrel down on you in a heartbeat.
I wouldn't mind driving 60 on the highways if it saved gas. But it often feels like the other drivers literally will not let me drive that slowly.
By Unknown, at
Tue Jul 08, 09:27:00 AM:
About a month ago my wife and I noticed that people were doing the speed limit here which is 60. I told her it would last about a month before people got uncomfortable with going that slow. I was wrong, it lasted about 2 weeks!
By , at
Tue Jul 08, 09:30:00 AM:
My parents live 380 miles from here. At 55 that is 6.9 hours. At 80 that is 4.75 hours. I have made the trip at both speeds. Going 80 is a safer as it is easier to stay alert 5 hours vs 7. (Texas did a study that showed higher speeds saved lives on some long, empty stretches of highway and raised the speed limit to 80.)
My SUV get 29mph highway. I don't think that I would save enough money to make up for the 2 extra hours on the road. It cost me less than $50 for gas on the trip I made last month. If I could have saved 10% I could have saved $5 at the cost of 2 hours of my time. Even if I could have saved 50% ($25) it would not have been worth it. My wife was with me, so 2 hours time x 2 adults is 4 hours. $25/4=$6.25 an hour. It has been a long time since either of us made that little.
By , at
Tue Jul 08, 09:35:00 AM:
I don't have any proof, but I do think that speeds have decreased locally. Obviously, that's just my observation and it is where I live. But on those key roads where traffic travels 35, 40 mph, I definitely get a sense of some people slowing it down. You do get better mileage, and given that the journey is presumably short, maybe you are willing to swap that time for some savings. But if you're going for hours, it's different.
By wpw, at
Tue Jul 08, 09:40:00 AM:
Interestingly enough, my little RAV4 gets substantially better mileage at 65 MPH than at 55 MPH... I consider 15% to be substantial.
I think perhaps the 55MPH "savings" should be revisited in light of changes in shapes and materials in automobiles in the last 30 years.
In 1979, the "average" American car was a boxy vehicle with hard angles and a basic upright windshield... not particularly aerodynamic. Nowadays even the UPS vans are aerodynamically shaped.
When was the last time any scientific checks were made to the "drive 55" figure? Perhaps this too is an incovenient truth.
ps - in NJ, what you think is a route number is actually the speed limit (78, 80, 95, etc.)!
By Donald Sensing, at
Tue Jul 08, 09:53:00 AM:
66 mph? Pokey! I drove Sunday 300-plus miles on the interstate, speed limit 70 most of the way, 65 the rest except for a few congested miles in a city. I use my Tomtom 920 GPS as my speedometer because it is much more accurate than the car's. (At interstate speeds, most cars' speedometers will read high.) I set the cruise control four mph higher than the speed limit. I was routinely passed. I didn't count cars, but the number of cars I passed was dwarfed by the number than passed me. And most of those who passed me blew my doors off doing so.
For business drivers, time really does equal money. For everyone else, time may not equal money per se, but the opportunity costs of driving slower to save gas are not being met, overall, by the savings gained from slower speeds.
When I return home this week, dropping my speed by 10 mph will add 48 minutes to the trip. If I got 5 mpg better fuel economy, I will burn 1.41 gallons less. At $3.85 per gallon, which is what gas sells for along the route in several places, I will save $5.43, or $6.78 per hour. It's very much worth that much to me to get back to my family more than three-quarters of an hour sooner, as well as get out of the car that much quicker.
So while I definitely am driving less often to save gas money, I see no reason to slow down to do so, at least not yet.
By , at
Tue Jul 08, 10:04:00 AM:
Well, many in government would love to impose this ridiculous scheme. I think the reason is not so much to save gas but rather to condition the public into accepting big government edicts, you know, changing citizens into serfs.
By Seerak, at
Tue Jul 08, 10:15:00 AM:
Here in Los Angeles, I have actually noticed a small shift towards lower speeds -- but *only* during regular commuting hours (7-10AM, 3-8PM), and only by *some* commuters. (This is distinct from a reduction in overall traffic, which I have also noticed).
I think the difference lies in three things:
1. Cali has the most expensive gas in the nation (average $4.58 as of yesterday)
2. Commute traffic, being daily, has enough accumulation to make a noticeable difference. Non-commute (Weekend, evening) traffic consists of more "occasional" drives, where the gas savings don't accumulate so much -- and congestion is less.
3. Commute time here is already quite long for many people due to congestion, enough that the time benefit of going faster is negated -- so why not save some gas?
In my case, I have a 110 mile round trip commute in a hybrid that tops out around 60mpg in the summer, with my current quasi-hypermiler driving style. Doing 70 instead of 60 (no traffic) would net me 18 minutes total per day, but would cost me about 6mpg, which is around 1 additional gallon per tank to cover the same distance. I fill up 5 times a month, so 5x$4.60=$23.00 savings at the cost of 6 hours, per month = $3.83/hr... not even minimum wage :)
I do know from experience that driving style makes a HUGE difference in MPG. If I were to revert to my pre-hybrid driving style, my "hourly rate" would probably double (~48mpg) -- and I expect (but do not know for certain) that a bigger vehicle might see an even bigger jump. For someone making $10/hour and driving a truck, it gets really close to being worth it.
By , at
Tue Jul 08, 10:15:00 AM:
It's not clear to me that you save as much gasoline at turnpike speeds going 55 as going 65+. In the 1970's overdrive transmissions were pretty rare, these days most cars have them. Coefficient of friction (Cx) is probably much better, too (except for boxy SUVs). In the 1970's it was true that 50 mph was the most efficient speed, but that may not be the case in the 21st century.
By , at
Tue Jul 08, 10:20:00 AM:
How about this: at 55mph driving/riding is extremely boring, and likely to lull you into distraction with other things like cellphones, kids, radios.. In the NYC area I have even seen town car drivers reading the f00kin newspaper!
At 85mph+, your attention is fixed to the road. There is a reason Germans never even thought up cupholders and find them baffling. As a motorcyclist, I would far rather share the road with people doing high-speed whilst paying attention than slowpokes who are doing 3-4 things at once besides driving.
In any case, keep right except to pass, and use your xenudamn turn signals!!
By , at
Tue Jul 08, 10:47:00 AM:
Actually, the 55mph as best economy theory is incorrect. Due to wind resistance, proper tire size, engine rpm, and drive gearing, ect. the best economy is achieved at 70 mph!
We are actually losing some fuel economy these days by mandating that cars get best fuel economy at 55 mph. Just ask any aftermarket tuner what happens to cars once they get rid of the factory imposed fuel/air and ignition maps on a car. Everything improves: power, economy, torque, etc.
Just another example of bad legislation forced through Congress by the enviro-jerks making things worse for everyone.
By Rick, at
Tue Jul 08, 11:00:00 AM:
I kinda like slower driving. It saves a few bucks, but I also just enjoy scenery and listening to the radio and being away from everything else I have to do. I'd be happy with a 55 speed limit for my own reasons although I realize it doesn't work for most people and also I realize that too much speed differential in traffic is unsafe so I tend to just go with the flow of traffic and slow down when it's safe.
By plutosdad, at
Tue Jul 08, 11:44:00 AM:
The problem is people don't actually SEE the change to their wallet.
If the government wants to mandate something, it should just mandate the mileage gauges that hybrids have be installed on all new cars. We'll have to pay a few extra bucks for a new car, but we'll get a gauge that gives us instant feedback on our driving.
Only then will we see people changing habits. If someone values time over the cost of extra gas, they will drive faster. If someone doesn't, they'll slow down. But it will be their choice, and the gauge will give them the information they need to make that choice.
By , at
Tue Jul 08, 11:46:00 AM:
Re Gas a good value. Out here in rural Nebraska, I have noticed RV traffic has dropped by perhaps 90% this summer. Normally I see these vehicles all the time. This summer I have seen very few. McCook NE has a very nice free RV park and it is usually full all summer. This year I have never seen more than 2 or 3 parked there. My 'next door' neighbors have just moved to town. Apparently living in a house for free in the country can't compensate for the price of gas for the commute to town, and yes they own gas hogs.
By Joe, at
Tue Jul 08, 12:12:00 PM:
This comment has been removed by the author.
By Joe, at
Tue Jul 08, 12:13:00 PM:
Putting aside wind resistance, fuel economy is not a function of speed but of RPMs. All internal combustion engines have a sweet spot where they get maximum efficiency. Depending on how a car is geared and its aerodynamic efficiency, the optimal speed on a flat road with no wind will rarely be 55. My 1999 Honda Civic hits the sweet spot between 70 and 75. My current three and six week rolling averages just exceeded 40 mpg.
The best mileage I've gotten with my 2001 Honda Odyssey mini-van is 25 mpg at 70 mpg with cruise control.
By Joe, at
Tue Jul 08, 12:22:00 PM:
Another point. I spend about $150 a month on gas for my Civic. That's peanuts. Even if 70-75 wasn't the sweet spot for my car, I'm more than willing to pay the truly tiny difference in cost so I can get to work and home faster. (I'm also willing to pay a few bucks more to keep my house at 78 degrees in the summer and to run a faster computer at home.)
By , at
Tue Jul 08, 12:25:00 PM:
I think there has been some reduction in discretionary driving, even here in NJ where gas is (relatively!) inexpensive. My hobby is racing and tracking sports cars and I can report that attendance at these events is down - in some cases significantly - from last year. Bear in mind that just getting to the track requires either (a) a long drive in a gas-guzzling sports car or (b) a long drive in a gas-guzzling SUV or pickup towing a heavy trailer. Not a cheap hobby. Then there's the track driving itself, with the gas pedal spending most of its time on the floor. And God forbid you have to buy fuel at the track.
TH: We call cars like yours a "rolling chicane."
By Purple Avenger, at
Tue Jul 08, 12:26:00 PM:
my little RAV4 gets substantially better mileage at 65 MPH than at 55 MPH
Undoubtedly an automatic tranny. Watch carefully, and you'll likely feel a shift point to a higher ratio gear some point after 55mph.
There is no other possible explanation for this behavior. Gaming the highway mileage with a very tall 5th gear is a common trick of Japanese car makers. On any incline of more than a few degrees, the thing will be compelled to downshift itself.
Aerodynamic drag at 65mph is ~25% higher than at 55mph. Drag is a nonlinear function. Its a function of velocity squared. This is an unbendable property of fluids (air is a fluid).
By Joe, at
Tue Jul 08, 05:21:00 PM:
And your point is?
Seriously, this is stupid. Drag is also higher at 55 than 30. Should we get rid of that damn third or fourth (or higher) gear too?
This isn't "gaming the highway mileage" it's smart engineering. It gets the engine to run at an optimal RPM.
Regardless, it shows that this meme that you save money by driving slower is bullshit and some of us are really tired of hearing the self-righteous lectures. (Especially from people driving six or eight cylinder cars or non-subcompact four cylinder!)
By jaycaruso, at
Wed Jul 09, 12:29:00 PM:
People go faster simply because they can. Today's cars, even the 4 cylinder ones (like my 2003 Accord) can do 80mph easily. When many street roads have speed limits of 45-50mph, it's almost unheard of to do 55mph on the highway.
I live in Florida and commute 30 miles each way to and from work. I normally do around 75mph and even then I have people zipping past me. Where I live, a person doing 55mph is more likely to cause an accident than anything else.
