The slow car movement

Easing off the gas eases gas use

Posted by Eric de Place (Guest Contributor) at 12:32 PM on 28 Apr 2008

Read more about: fuel efficiency | energy | green living

A few weeks ago, Clark wrote about truck drivers slowing down to economize on fuel. It's a great story, but was it a real trend or just anecdotal?

Photo: Pietro Izzo

Well, I'm here to report that there's some truth to it. Or at least some truthiness. A recent Congressional Budget Office paper examining the effects of gas prices found this: "Freeway motorists have adjusted to higher prices by making fewer trips and driving more slowly."

That's surprising to me. I mean, I don't slow down when gas prices are high; it would never occur to me. Do other folks?

But whether it occurs to anyone or not, it is a rational response to high prices, depending on the circumstances. As the paper explains, slowing from 70 mph to 65 mph reduces a typical vehicle's fuel consumption by 8.2 percent. That adds up eventually, but whether it's worth it depends on how much you value your time. (It also depends on how pricey gas is, and how efficient your car is.)

So the paper crunches some additional numbers -- fascinating stuff, I assure you -- and finds that freeway speeds really did decline as gas prices rose. Not by much, mind you, but a little: about a teaspoon of fuel every 2.6 miles. There's almost no way that the results are intended; it's almost like individual irrationality adding up to collective rationality. And the paper sort of hints at that:

Such small responses are unlikely to result from conscious calculations. Few motorists would have the information required to gauge their responses so acutely, nor the time or inclination to do so. However, higher prices make drivers pay more attention to speed. The modest reductions in speed suggest that drivers may have responded by easing off slightly on the gasoline pedal or dialing back the cruise-control settings a notch. If only a minority of drivers have that response, their reduced speeds could cause nearby drivers to slow down as well, even if gasoline prices alone would not have that effect.

The upshot, I guess, is that there's an easy way to save the planet. Just reduce your fuel use (and everyone else's) by getting in the left lane and driving 45 miles per hour. Folks may not appreciate you at first, but you can just hand them the CBO paper and talk about elasticity of demand. They'll come around soon enough.

Good luck!

For story: The slow car movement
29 Comments | Post a Comment

drive-easy-conserve

If you drive slowly to save fuel, then get yourself one of these bumper stickers to warn or educate:

http://www.greenslowmovingvehicle.com/

The originator of this grassroots effort has been distributing these stickers all over the country and has started seeing them on strangers' cars around his home of La Crosse, WI.

Erik

The Orion Grassroots Network: 1,200+ grassroots groups working for conservation & more

by Erik Hoffner at 12:40 PM on 28 Apr 2008

trucks yes.

At least the major trucking corps have crunched the numbers, and reduced the speeds they set the governors to. It is possible that slower trucks, are on average forcing cars to slow down.

In my case, I think it is working in the reverse, as fewer cars are taking my commute (this is much much more due to the housing crisis than gas), congestion has decreased.

I wouldn't recommend trying to force others to drive slow, you might be the victim of road rage.

by bigTom at 12:43 PM on 28 Apr 2008

Slower = Saving

No surprise - this is physics 101. Friction increases with the square of speed. At fairly low speeds, 30 MPH according to wikipedia, friction due to air resistance starts to dominate the equation.

http://en.wikipedia.org/wiki/Fuel_economy_in_automobiles

Driving the speed limit definitely saves money.

by kwaldman at 1:01 PM on 28 Apr 2008

I've noticed

I was driving behind a Staples delivery truck the other day, and there was a sign on the back that said (paraphrasing): "Maximum speed set to 60 mph; uses less gas and creates fewer emissions." I remember thinking that it must be really annoying for the driver, because 60 mph on the typically-moving-80-mph Interstate 684 doesn't even feel safe, but that it was a great idea from a corporate and environmental standpoint.

Anecdotally, I have noticed that people are driving just a bit slower than usual in the last 6 months or so; maybe 70 on the Thruway instead of 75 mph, and similar ~5 - 10 mph differences on the SawMill Parkway and I84. But I have also noticed that there seem to be a vast number of police cars out monitoring the roads these days, and maybe it is that that is keeping traffic closer to the speed limit.

by kmp at 1:06 PM on 28 Apr 2008

Speed still kills

In the '70s we reduced the speed limit to 55 mph nationally. Not only did we save some fuel and produce a wee bit less pollution but we immediately slashed roadway deaths to one-half of their previous level.
Of course, the only way to make sustainable use of our highway infrastructure is to return the paved surfaces to their original purpose: bicycle use. These Johnny-come-latelys in their CARcinogen-spewing fossil-fool powered wheelchairs are rather rapidly destroying the biosphere and I, for one, question their right to pollute the environment for their own nefarious motives.

by human power at 2:15 PM on 28 Apr 2008

It's not just speed but acceleration

Jackrabbit starts burn through a lot of fuel. In the city, I am constantly catching up to cars that sprinted away from me on the green light and then had to slam on their brakes at the next red light. Press the gas a little more gently when accelerating and take your foot off the gas a lot earlier to reduce braking.

by katakanadian at 2:32 PM on 28 Apr 2008

responding to fuel prices

"That's surprising to me. I mean, I don't slow down when gas prices are high; it would never occur to me. Do other folks?"

YES. I've modified my driving habits to reduce braking... anticipate stop signs and red lights, slow down before sharp curves on rural highways... no more jack-rabbit starts and stops. I get out of the way of faster vehicles. My goal is to get from point A to point B, alive, not win a NASCAR race.

Regarding 65 vs. 75 mph, I can apparently save over $20/month driving the posted speed limit. Increasing from 65 to 75 mph, would cut only 3 minutes -- tops -- off my 38 minute commute. I waste more time than that before I leave the house or posting comments like this one. I'd rather have the $20/month or $240/year.

Also, I've calculated the cost of running an errand to the nearest "urban" area. I generally like to stay home if I don't have to go to work. Now I know it costs about $7.00 to go to the grocery store, hardware store, post office, or library if I'm not already out for some other reason. Pay $7.00 to return an overdue book? NO WAY! I'll wait until Monday and pay the late fee.

Forcing others to slow down? That's crazy! You're more likely to find yourself dead, or find some innocent person driving nearby dead, than to impose your morality on the fool riding your bumper.

by wiscidea at 2:44 PM on 28 Apr 2008

no one would do it, but

I suspect a meter ticking off how much you're spending on gasoline as you drive would help a lot of people reduce their use of automobiles and perhaps demand better fuel economy.

by wiscidea at 2:46 PM on 28 Apr 2008

Doesn't the Prius

have a fuel efficiency gage in the dash? Not exactly like see dollars & cents, but it's got to affect your driving if you slow down a bit and see "45 mpg" rather than vrooming up a hill and seeing "5 mpg."

Although vrooming up a hill is fun sometimes....

by kmp at 4:05 PM on 28 Apr 2008

I've been doing it for a couple of years now

I live 30km from the nearest town, and 200km from Melbourne. Here in Australia the price of fuel is now at the equivalent US$/Gallon. When I can, I drive below the limit, minimize acceleration, allow the car to decelerate going up hills and then gently accelerate going down hills. I've found I can shave 10-20% of my fuel bill.

by picoallen at 5:37 PM on 28 Apr 2008

55 mph value

It's not entirely clear what a reduced speed limit would save. Gas? Less than 25% of our mileage is on interstate highways. Many of the heavily traveled sections of interstates are already 55 mph. Slowing on the highway does reduce consumption, but this is already at a fairly efficient level compared to city driving. After the 55 mph experiment in the 70's/80's I believe the DOT concluded the savings was on the order of 2%.

As far as saving lives, that is debatable. Common sense would indicate that but the data is less clear. Yes, fatalities did decrease, but much of that was the result of lower number of miles driven. Also, when the speed limit was changed in 1973 there were many cars on the road with little or no safety equipment and that rapidly changed over the next few years. The University of California did a well known study that indicated that fatalities decreased as much when the speed limit was increased in the mid 90's as they did when the limit was decreased. With improvements in roads, cars (and enforcement) fatalities seem to decrease independent of speed limits.

by KenG at 5:52 PM on 28 Apr 2008

Uhh left lane?

You mean block traffic? That'll get you pulled over or even killed. I drive slowly in the right lane, and squeeze over for people to pass. And get ready to pull off in an emergency, say if a drunk driver is approaching at high speed.

They lose their depth perception and motor response.

I think a great way to really save a lot of gas is to put bike lanes beside the highways. The pavement already usually extends 2 feet past the edge of the lane. So widen it 2 or 3 more feet.

Then people would bike more. With plugin aided bikes, people can commute. and the speed, around 20 to 30 mph would get you to work much faster in traffic jam areas. I saw a news story of a chicago worker driving 30 miles to work, it took 90 minutes one way, because of traffic. You could make that faster on a plugin bike, and get a nice work out.

Meanwhile, could we consider making the right lane a 45 mph lane? That way we slower drivers could choose to save gas, safely. Don't try to impose lower speed limits, it's a bad idea. The system uses it as a revenue source and angers we the people. Selective enforcement, gotcha governance is annoying and bullying.

It erodes respect for law enforcers and the justice system and destroys our basic rights. The right to a fair government. What's next? Torture?

Don't laugh, Scalia just said in a teevee interview that since torture is not "punishment" as in the constitutional prohibition on "cruel and unusual punishment", the court has nothing to say about torture. "Punishment" under Scalia's argument, is only what happens after conviction, the actual prison sentence or fine.

Thus torture is aok before conviction! now that's justice. Hehey.

It's a slippery slope, from handcuffing a rowdy woman at the airport and letting her die by inattention, to chasing people for speeding, getting angry, and tasering them when the police catch them. We have all seen it on those cop shows. We have also seen people die in police chases for speeding.

Listen to the libertarians on this one, make going slow voluntary. Don't make it a matter for the police, who have much better things to do, like stopping actual violent crime.

I was pulled over for going 35 in a 55 mph zone, evidently it fit a profile for suspicious behaviour, hehey. I just didn't want to hit those deer in the road. Whoops.

http://amazngdrx.blogharbor.com/blog

by amazingdrx at 7:10 PM on 28 Apr 2008

Europe

does this, no? The major highways have 60, 80 and 110 kph 'lanes.' In my experience, everyone obeys these norms on the highways... it is only in the cities that they drive like madmen (which I am quite used to, having cut my driving teeth in Boston).

But Dr.X, would you really want to ride your bike alongside the highway, with people buzzing by at 75 mph? Hell, I don't even like to ride on my country road, with a speed limit of 40 mph. Granted, there is no shoulder, and that is mostly why... but even with a big shoulder I can't imagine I would opt for a bike commute on a highway. Not to mention that it is currently illegal. The potential for really bad accidents seems quite high.

by kmp at 8:03 PM on 28 Apr 2008

Gas Cap

I just read one study that said that something like 14% of all gasoline is lost -- as gas vapors because people either don't screw on the gas tank cap tight enough or else have a leaky cap!!

It's the little things...

Texeme.Construct(function(x)=Participation(x))

by jabailo at 8:55 PM on 28 Apr 2008

Oh

I didn't mean on freeways KMP. I think enough routes could be chosen off the freeways to route the beside the road bike travel. I would prefer separate bike paths of course, but it would be hard to do except in a few areas where right of way like old railway beds are preserved. or through parks.

But even on freeways the ultra slow lane could be good. Small electric cars could cruise at under 40 with hardly any energy cost compared to gas guzzlers that move even slower in jams. with an under 40 car, automated steering would be easy, these little cars could be steered along in zero wind resistance, ultra-efficient, traffic jam resistant trains. we got a great big tiny convoy...

I was pulled over where no minimum speed was in effect, off freeway. Slow driving, it's unamerican.

http://amazngdrx.blogharbor.com/blog

by amazingdrx at 9:16 PM on 28 Apr 2008

All cars need instantaneous fuel efficiency gauges

I bought a civic hybrid about 2 years ago, and it dramatically changed my driving habits. I am a much less aggressive driver now because I get instantaneous feedback about how my driving behavior affects my fuel efficiency. If all cars were equipped with these guages, then everyone would know how aggressive driving and speeding reduce their fuel efficiency.

by Ariell at 6:01 AM on 29 Apr 2008

rails to trails

"...except in a few areas where right of way like old railway beds are preserved..."

Emerging conflict... It looks like some of the preferred bicycle commuter routes are former rail beds. There are a couple nice trails in Dane County, WI... fairly level, direct, bridges over streams, raised bed though wetlands. But now folks are interested in trains again. Who will win?

Will certain groups resist the conversion of bike trails back to train tracks?

I suppose we could leave the bike trails alone and construct new rail beds. But then there are the issues of private property vs. public interest, as well the the destructive nature of constructing new rail lines by plowing through residential areas... sort of like the contruction of highways.

by wiscidea at 6:15 AM on 29 Apr 2008

What about tire inflation?

No one's mentioned tire inflation. I still don't understand the difference between tire and car manufacturer recommnended differences. Probably car is calibrated at one level and tires can take more.

With an aging population and a lot of mediocre drivers out there on top of that, mass transit should be expanded instead of being cut because of budget cuts and the increased cost of fuel/energy.

It's time to see "End of Suburbia" again. Especially appropriate now with CA gas prices over $4.

by baysidebill at 9:12 AM on 29 Apr 2008

nitrogen

Good point, Bill.

Tire shops this area are starting to offer to fill your tires with nitrogen gas - it doesn't expand or contract as much with hot/cold weather, and the tires keep pressure much longer with nitrogen: the molecules are big and take a long time to migrate out of the tire. So it's possibly a good way for folks to maintain optimal tire pressure for good mileage and better tread wear, which is itself a good conservation point, money wise.

Erik

The Orion Grassroots Network: 1,200+ grassroots groups working for conservation & more

by Erik Hoffner at 9:20 AM on 29 Apr 2008
[ Parent ]

Nitrogen is Bogus

The whole nitrogen in the tires bit has been put to bed long ago. Air is already almost 80% nitrogen. The difference in size between a nitrogen and an oxygen molecule is inconsequential. The expansion and contraction effect is limited to the water content. Any correctly installed compressed air system already has a moisture filter. It's all just a profit add on for tire shops.

Also the correct tire inflation is easy to understand. The pressure on the tire itself is a maximum that the tire can safely be inflated to. The door sticker on the car tells you what the manufacturer recommends as the best compromise for handling, ride and safety. You can overinflate your tires to the sidewall rating and gain some gas mileage at the expense of ride comfort and potentially loss of handling and grip.

by KenG at 9:54 AM on 29 Apr 2008

grip

"loss of handling and grip"

So you're saying you can get better mileage, but you might lose control and/or just fly off the road?

Statistically speaking, will CO2 emissions be lower because of improved mileage or higher because of more dispatches of EMTs, medical care, and manufacture of replacement vehicles?

by wiscidea at 10:14 AM on 29 Apr 2008

Commuter rail

That light rail can go on freeway medians in tubes wisci. in a tube you can go really fast with safety and with electric powered trains. Built like aircraft, they fly along on the pressure wave inside the tube.

Minneapolis is already doing the freeway median light rail I heard.

Bike trails are fantastic, I think resistance could be overcome. Tell the sedentarian un-bikers that it will lower the demand for gasoline and the gas prices they pay.

http://amazngdrx.blogharbor.com/blog

by amazingdrx at 11:44 AM on 29 Apr 2008

Every bicycle on the road...

... translates into lower fuel costs, less congestion, and more parking spaces... should be an easy sell. Why won't suburban road warriors support this?

by wiscidea at 11:49 AM on 29 Apr 2008
[ Parent ]

Because

road construction is paid for by taxes, and most people don't bike, so most people are paying for something that they won't use. Road construction slows down traffic, making an already long commute even longer.

I'm not saying that I wouldn't love it; my sole disinclination to road-riding where I live is that none of the roads have any real shoulder and cars are traveling 50-60 mph. But it would not be an "easy sell" unless far greater numbers of people were willing to bike (as tranportation) on a regular basis.

by kmp at 12:06 PM on 29 Apr 2008

Tonight.

I will do this tonight and watch all the vehicles pass. Cruise Control is a good thing for this.

The war for oil is a war for the beast The war on terror is a war on peace -Franti

by TheAnalogKid at 3:03 PM on 29 Apr 2008

Handling

"So you're saying you can get better mileage, but you might lose control and/or just fly off the road?"

Yes, there is a problem with being a fanatic. If you visit the hybrid car forums, you will find there are people out there running 60 psi in their tires, driving 10 mph under the speed limit in heavy traffic or drafting semis. It's not worth it to save a couple of gallons of gas.

by KenG at 4:36 PM on 29 Apr 2008

Plugin hybrid bike or..

..Plugin hybrid hypercar? Both.

Tiny 55 mph top speed plugin hybrid hypercar. This type of car, with it's very own slow lane on freeways could save enough gas to lower prices for drivers of gas guzzlers.

How much fuel would a 1000 pound vehicle about the size of a mini-cooper take? It could go 80 miles on batteries, then even on fuel it would get over 100 mpg. Cruising at 45 mph.

Air bags all around and carbon fiber around the passenger compartment, foam/fiberglass bumper and fender, doors and body panels and an aluminum tube roll/crash frame. That's an affordable alternative. In mass production these could be sold for 10k. A 10 hp gas or biogas flex fuel generator (Honda makes them, very quiet and efficient), 4 kwh storage capacity worth of batteries, a 25 hp golf cart motor, this is well known technology.

Robotic factories could turn them out like hotacakes.

And plugin assisted bikes already exist, and are wonderful according to the videos presented here of bio-d's hybrid and others.

Human/electric bike or flex fuel gasoline/biogas/electric car. Both. And electric mass transit, buses and trains you can park your bike on.

I think 60% of car owners could get by with these. Plugin bike and ultralight/small car. Small but ultrasafe with extra forgiving, impact absorbing design, carbon fiber tub, and air bags. Also a nice seat belt system.

Park an old gas guzzling truck or van, or rent or borrow one. When you need to haul heavy stuff.

But for commercial needs, heavier trucks could be plugin hybrids too.

http://amazngdrx.blogharbor.com/blog

by amazingdrx at 6:49 AM on 30 Apr 2008

The other alternative

Jim Kunstler outlines that in his book. Horses. After the fall of techno-civilization.

I think going to the hypercar/bike thing now is prefferable. Armageddon? Not so much.

http://amazngdrx.blogharbor.com/blog

by amazingdrx at 7:00 AM on 30 Apr 2008

N2

Not that I'm shilling for tire dealers and their nitrogen programs, but air is only 3/4 nitrogen, and its a big difference to put 100% nitrogen in there if it leaks out more slowly. But whatever. If it helps some people keep their tires inflated for just that little bit longer, I say why not.

Lower speed limits is a better idea though.

Erik

The Orion Grassroots Network: 1,200+ grassroots groups working for conservation & more

by Erik Hoffner at 7:52 AM on 30 Apr 2008
[ Parent ]

ADVERTISING POLICY

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