Sentence of the Day

…whatever some Prius fans may believe, it turns out that Priuses do have a corporeal form, and a Prius in congested traffic will cause more emissions indirectly by slowing other cars down than it will emit directly.

From Tim Harford’s excellent Adapt.


And that's why we should buy gas guzzlers, since unlike Priuses they have no corporeal form!

Increasing congestion makes it sound like the choice is between driving or not driving, not between types of cars. It seems the more relevant comparison would be between types of cars, if the person has already made the decision to drive a car rather than using an alternative type of transportation.

Entirely. The prius owner would cause congestion emissions if s/he was a landcruiser owner. There is nothing prima facie that suggests the a prius owner would cause more congestion.

of course, i haven't read the book.

Tim is suggesting that Prius stay home, and leave the road to Escalades ... because the Prius driver must have his heart it the right place already and the Escalade driver is irredeemable?

From listening to Harford on "More or Less", he sounds more like a bicycle guy than an Escalade guy, although he could certainly afford the Escalade.

(The continued irrational response to hybrids really does sadden me. Harford and Tabarrok catch a societal meme, something like "let's think of some reason, any reason, to ignore the engineering benefits of hybrid drive.")

I don't know about that. Hybrid technology is definitely interesting. It's just that by actual numbers it's not yet a no-brainer that you buy one unless your friends think it makes you cool.

Yup, while I agree that a lot of hybrid-bashing is pure venting, the engineering is hardly an obvious win.

In fact, it seems fundamentally handicapped by the need to carry around two entire drive-trains, with all the inherent weight and reliability problems inherent in that. If I was making a technical bet, I'd say pure-hydrocarbon or pure-electric represent better solutions. Hydrogen doesn't seem ready for prime-time, and doesn't seem like much of a technical win, either.

But hybrids have totally won the signaling war. The same kind of people buy Priuses as buy Hummers - people looking to clearly signal their affiliations. They happen to be opposing affiliations, but that's a detail. A Prius is a showy purchase. Maybe that will save them, if the fad lasts long enough.

The key difference is that a Prius costs less than the average new car, but you somehow still perceive the buyer as rich, in the same class as Hummer buyer ... who pays twice as much as the average?

I see a Prius buyer as someone who disregards facts and drives around in a "Look at me! I'm great!" sign. Just like a Hummer driver. Look, surely some Prius drivers are just duped, and not consciously disregarding the environment. I don't view them as evil.

Have you ever met Prius drivers? At least in the early days, they were a special kind of person.

Keeping your old car is almost certainly a better environmental decision. Buying a new non-hybrid is also a better decision, if you really need the new car. Buying used is also a good choice.

This comments reads a little harsh, particularly as I scroll down and realize John is a brand-new Prius owner.

Sorry, John, I wasn't very tactful here. As far as I can tell you're honestly mistaken and not trying to be a jerk about it. I certainly know smart people who've bought the Prius.

The thing of it is that the Prius is a very expensive car for its size. A comparable gasoline car (e.g. a Corolla) costs about $7000 less, and the difference will never be recouped from fuel savings, since a corolla isn't exactly bad on gas. Even allowing for a $3000 NPV benefit on the gas, a Prius driver is spending a good amount of money on signaling environmentalism. Not that there's anything wrong with signaling per se, I mean, that's the purpose of college.

FWIW, the EPA puts the Prius and the Corolla in different vehicle size classes. The Prius is one up. Now, I get that from the outside it looks like a small car, but try looking at the car next to it, and compare in height and width. It's like the shape of a small car, inflated. That tricks the eye.

The Prius has basically the same interior space as the Corolla, though.

The hybrid might be new to automobiles but heavy equipment has been hybrid for a long time. Most of the diesel locomotives, ships, large earth-movers etc. have a diesel prime mover driving a more versatile motor. The system might look idiotic at first glance given the inefficiency of a engine and then a motor, the higher weight and complexity etc. Notwithstanding it has been the dominant choice.

Of course, that says nothing about the suitability in cars (where the hybrid design is much different). All I am saying is that hybrids do make sense (in certain situations) from an engineering POV. It's a more nuanced argument than "Let's all use hybrids" or "Hybrids are dumb".

Actually, it's more precise in most large diesel-electric (and nuke-electric) systems to say that they use electric powertrains, but have onboard diesel power stations. The key point is they don't have mechanical transmissions connecting the action of the power plant directly to the wheels/props, but use electricity instead.


The main drawback is carrying the batteries. Everything else is more reliable (electric motor/generators are more reliable than gas engines) or simpler (static planetary gear set versus manual transmission clutches or automatic transmissions). Even the gas engine in a hybrid is smaller and more efficiently run. The high-torque of acceleration is handled by the electric side, so you don't need a big block engine to get the car moving.

I don't the point of the quote though, Priuses are just as quick off the block as other cars in normal driving. I don't see everyone squealing out from a stop light.

The point of the quote is that Prii are just as SLOW off the block as other cars in normal driving. So they do slow down other traffic, just as all cars do.

Unless we legislate that everyone must drive a twin turbo V8 and must, by law, leave each and every traffic light at 5000 rpm and at 20 psi of boost. For the environment.

The easiest win for a hybrid is when a middle-class buyer "downshifts" to it. If my previous car cost more, got poorer mileage, and cost more to insure, then I win on all three. Last time I checked, the average new car in the US sold for about $27K. You can get a somewhat upgraded Prius for that, but if you have discipline, you can opt for the $22K model as I did. Certainly though, with the average at $27K half are paying more already, for whatever perceived benefits.

Really, this "makes you look cool" thing is an odd indictment of that. If your fiend bought a Mustang for the same money, would he not be trying to look cool? Is there any car, or any human actually, who can remove how they'd look and feel from the equation?

Regardless, if we DO remove the cool component, we do have that car that for many costs less, uses less, and insures for less.

Costs less than the average new economy car?

I would (for the most part) HAVE to buy a new Prius to get a Prius. I never buy new cars because they are economically inferior.

"Is there any car, or any human actually, who can remove how they’d look and feel from the equation?"

You obviously haven't seen my hoopy. My car said it hates being seen with me.

I understand what you are saying, and if you are a genuine Corolla or Civic driver, the comparison works differently for you. But what about, say, an Acura driver?

What I find is that Acura drivers talk about Corolla what-ifs, even when they'd never be caught in one. long as you have the money to appear cool/elite/righteous. I agree with you for once...

I love Larry David for a number of reasons, but he is a perfect example of the elite liberal clique - Prius and all.

In other news, water is wet...

Yes seriously, shouldn't it be pretty obvious that not driving AT ALL is going to better environmentally? Hopefully no one is so caught up in Prius worship that they would think otherwise. Pretty banal point.

But I do think that's exactly the point. Human beings like to gloss over the obvious points like "it's pretty obvious that not driving at all is better for the environment".
Although I do think the better parallel here would be carpooling than not driving. Carpooling effectively cuts your tailpipe emissions in half and gets you to work marginally quicker by taking one car off the road.
This also speaks to the "empty bus" effect. A bus with only four people on it takes up about half the road required for those riders riding individually in 4 separate cars. So even though the bus looks huge, empty and inefficient (and in many ways it is). Its impact on traffic and other car's emissions is far better than what can be done by shifting to a hybrid over even a motorcycle..

I do not know of Harford mentions it near that passage, but it has always astounded me to see heavily congested vehicles idling with the engine loaded against the brakes through the torque converter. While those vehicles will not capture the regenerative gains of a hybrid, certainly putting the vehicle in neutral and/or shutting off the ignition helps approach the emissions levels of the Prius. Automation is not required for that gain.

Many European (and other) countries have guidelines for idling engines (red lights, drop-offs, etc.) in order to lower emissions.

Isn't the engine idling when in neutral too? Is there a big difference in the idle speeds of neutral versus the foot-off-the-gas idle?

In every (non-hybrid) car I've driven, changing from Drive to Neutral while stopped pushes the RPMs up.

If you really want to reduce consumption you should turn the engine off. If your engine is completely warmed up, you are more than 1 car behind the red light, and paying attention to the cars around you, there is no time difference in getting started back up again.

Unless the Prius slows traffic down more than other cars do, it still has a lower net emissions profile because it's own direct emissions are less. And of course that includes extra emissions emanating from a Prius as a result of that other traffic, which will be less than the extra emissions emanating from most other cars as a result of slow traffic. So a traffic jam full of Priuses would be an "ideal" traffic jam.

Not that I drive a Prius myself or have any interest in doing so, but I don't see the significance here.

Yes, we should be asking "The Prius causes higher emissions compared to what?" Compared to another car, I don't see why it would create more emissions. Compared to no car at all, obviously any increase in congestion increases emissions.

It's quite a bit heavier than an equivalent internal-combustion-only car would be, and all the extra technology in it cost money (and energy) to design and manufacture. Resources that could have gone to other uses. The question is: does the extra energy recovered by regenerative braking pay for the extra weight that needs to be lugged around to provide it, the extra design and manufacturing cost, and the extra maintenance cost?

The answer is probably "no." Keep your old Civic if you care about the environment.

You know, if everybody in America drove a Civic, it would be quite a different world.

What we've got, strangely, is Civic drivers mad at Prius drivers because they think they are "better," while Mustang drivers are just "having fun" or something?

Humans are so strange.


The regenerative braking is not the only efficiency (not sure if it is the major one either). Getting an IC engine to operate closer to its optimum operating point (torque versus speed curve) is rather more important I feel. Especially in stop-start driving conditions.

That may be true, but it is irrelevant to the argument made by Tim Harford, and quoted by Tyler Cowen in the original post.

"all the extra technology in it cost money (and energy) to design"

This one shouldn't matter at all to prospective prius buyers as this cost has already been paid. It is sunk. They should be evaluating environmental effect on the margin.

Every morning I find myself cursing all the single driver hybrids overwhelming the HOV lanes...

This is totally unfair. Sure, a Prius in congested traffic causes more emissions" compared to no car at all. But the relevant alternative is not no car at all, but a standard car. Or does somehow having dual engines cause the Prius's "corporeal form" to bloat out so that it is much bigger than it seems, thus making congestion worse than expected?

Absolutely. How can Hartford make such a bad comparison. Obviously every new car adds congestion. The argument doesn't make much sense.

Sorry but Prius are a waste of resources. The amount of waste going into all the high tech components is much more than if you were smart and bought a 94-95 civic hatchback which will get you 40-50 mpg.

I think this is why Prius owners are such bad drivers. They can't see the bigger picture. They bought an ugly car out of a half-baked idea of 'sustainability'.

You sir, are typical of the emotional anti-hybrid contingent. Priuses do actually win at full life-cycle analysis, but do you care? No. You have an anti-emotion strong enough to override that.

Out of curiosity; can you link to a full life cycle analysis of the Prius? Or a break-even or cost of ownership analysis? It'd be interesting to make this discussion more quantitative.

I just tried looking at google-scholor. I didn't find the article I remembered. There were some Corolla-Prius comparisons, which I dislike because you are starting with a smaller and less expensive car. That isn't comparing an equally sized or equally featured vehicle.

Again, if you drive a Corolla already, good on ya. But then, in our imagined traffic jam, most people are not in Priuses, Corollas, or Civics.

Which car would you think is a fair equal sized and featured comparison to the Prius?

The Camry and Prius are very close. If I recall correctly, the Camry has a slight edge on passenger space, and the Prius has an edge on cargo space.

But really, we should look at the whole raft of less practical cars which people buy looking for other intangibles. You know, why in our culture is hybrid bad, but leather seats less so?

Leather seats help reduce the number of cows, which are responsible for significant greenhouse gas emissions of methane.

Do they really reduce the number of cows?

The Corolla is about as close to the Camry as the Camry is to the Accord in passenger volume. It is also about as close to the Prius as the Prius is to the Camry. The Camry is not a typical car in its class in interior room at this point.

The issue is that carmakers cannot make the Geo or the 94 Civic hatchback anymore. All the new emissions requirements in the 90's mandated a bunch of heavy equipment to burn NOx and SO emissions. The tiny 2011 Honda Fit, for example, is only 35/28 with all those catalytic converters weighing it down.

Of course, unless you drive 30,000 miles a year, the Prius does not make up its additional fixed cost. It is mostly a status symbol. People also don't realize that fuel mileage savings do not increase linearly. In fact, you get twice the savings from going to 10 to 20 mpg as you do going from 20 to 40 mpg. If you drive forty miles, a 10 mpg car uses 4 gallons, a 20 mpg car uses 2 gallons and a 40 mpg car uses 1 gallon. The utility of additional mpg increase pretty quickly.

It's best to get a decent 20-30 mpg car and then drive conservatively. Every time you use brakes instead of natural dampening, you are wasting fuel and making your car less efficient. I absolutely can't stand how people drive aggressively, just to get to a red light faster and use more fuel.

What additional cost is that Walt? As I say, most buyers now pay more.

They pay more, for more car. That $27K average includes luxury vehicles, SUVs, and other cars that include more features than a stripped down basic Prius. Your real comparison is not the "average" car but the non-hybrid counterpart of a stripped down Prius - which, I'm guessing, is a base Corolla or maybe a Camry. Is a Prius more expensive than that vehicle?

Well, that's a pretty subjective measure of "more car" isn't it? There are lots of "all show, no go" cars in the $25K-$30K range.

A Scion XD is probably the lowest impact.

Nah, it's the Smart Car. It gets great mpg and when it eventually does get run over by a Suburban the driver's carbon emissions drop to zero, permanently.

Hahaha, true. But that reiforces my motorcycle shilling even more.

Smart cars don't get that great of gas millage when compared to their class.

Sorry but Prius are a waste of resources. The amount of waste going into all the high tech components is much more than if you were smart and bought a 94-95 civic hatchback which will get you 40-50 mpg.

So the best choice is, everybody should buy a 94-95 civic hatchback and get 40-50 mpg.

Did I miss something?

It's so loud in here with all the axe grinding going on...

You might think being a vegetarian is good for the environment but the amount of green house gasses produced by producing enough calories to support someone eating a vegetarian diet are much higher than the amount of greenhouse gases released by your decomposing body if you just let yourself starve to death.

The point being we should introduce a gas tax or fuel efficiency standards to improve emissions.

I'm not sure I understand this sentence? Is Harford suggesting that not driving causes lower emissions than driving a Prius? Or is it a single Prius responsible for the 20 minute delay on the Holland Tunnel, and that it is a specific result of its Priusness?

He's saying that if the Holland Tunnel is at capacity, a single added Prius will make all the Expeditions wait a good bit longer. Once roads (or any type of constrained queue) are at capacity, queuing theory shows that wait times will hyperbolically increase (i.e. 1/x as x goes to 0). In those conditions, a Prius adds a lot more CO2 through the added emissions of other cars than its own, relatively tiny emissions.

I don't take the quote as a contrived argument against the Prius. I just take it as an example of how large subtle, indirect effects can be.

Of course it's contrived. Removing one of those Expeditions saves more CO2 in total, right?

Not necessarily, if the Prius owner feels so good about their mileage that they decide to drive a lot more to do even more good for the environment.

That seems very speculative. Do you have any data to support that assertion?

"I don’t take the quote as a contrived argument against the Prius. I just take it as an example of how large subtle, indirect effects can be."

Matt Waters, your comment made sense and was on topic, maybe the only one in this thread. I want to recognize that. I wish I'd said it.

Why stop at Proudest? Might not we blame EVs and bicycles for the same corporeality? Can't say that I'm very impressed with this argument.

Overall, you commentators should see that the shoe is really on the other foot. Read back this thread, and see who really is carrying the emotion on this question.

My Prius cost 30% less than my previous car, and over 95000 miles, I've saved about $7000 on gas. YMMV.

Then the obvious questions, what was your previous car and how much did/do you drive?

I'm old enough to have had quite a few cars. Before the Prius I had two, a Honda S-2000 and a Subaru WRX wagon. Quite different, eh? Anyway, I dropped to the S-2000 and the Prius, and then just the Prius. I've got 95000 miles on my 2005 Prius. (Funny actually how my previous two were for more "anti-social" driving, but that they got slagged less for that.)

If people are less upset by what you see as more antisocial, maybe you're wrong about what actually is antisocial?

And did all your kids go off to college?


Isn't it a good thing to support these in-between and "possibly not worth it" technologies because they are the stepping stones to better things?

I agree with this. It could lead to much better fuel saving tech.

I really don't understand those who criticize Prius buyers because they are trying to look cool, or are status seekers, or whatever. Here's a news flash: that's why lots and lots of people buy the cars they do. How many SUV purchases are practical, how many sports cars, how many luxury sedans?

Image and status is what a very high percentage of automobile advertising is based on. And it works.

It's the hypocrisy of conspicuous non-consumption, to coin a phrase.

At least the Mustang owners aren't kidding themselves. They know what they are buying.

Attempted theory of mind task. What's the evidence that the Mustang owners know what they are buying, or that the Prius owners do not?

A bigger p.....?

Could you provide some context? What point is Harford making? If he's arguing for arguing for congestion pricing, or public transportation, or other actions that would reduce the amount of driving time, then this is relevant. Though the only reason to bring up the Prius to make that point is for emphasis - he could just as well have said that even if you drove a magical car with no emissions, it would be better for the environment to drive less because your magical car would still take up space and slow down the other non-magical cars, causing them to emit more.

If he's claiming that the emissions reduction benefit of driving a Prius is overstated, then he's wrong. Let's say you switch from driving a car with emissions equal to X to driving a Prius which only emits Y, Y less than X. A naive analysis would say that you reduce emissions by X-Y. Harford brings up a more sophisticated analysis which incorporates the fact that, by driving, you cause an additional amount of emissions, Z, from other drivers. So switching to a Prius reduces your total emissions caused from X+Z to Y+Z, for a reduction in emissions of X-Y.

I think the point is pretty clear. If we imagine a traffic jam, with every car from an Acura to a Volvo in it, a certain kind of guy will pick out the Prius to hate on. It is a strange quirk of human nature.

I am not sure why that stupid red-herring was sentence of the day, except maybe that it annoys people enough to get their attention.
In congested traffic, a Prius does no more to congest other traffic than any other vehicle, except that it occupies less road space than SUVs and other larger vehicles. And since those other vehicles emit more emissions, their delay has more environmental consequence, but it is a very weird accounting that attributes those emissions to the Prius, instead of to the person that chooses to drive a high-consumption, high emission vehicle.

And the Prius cost of ownership is actually very low, because Prius depreciation is very low (sometimes even negative, in times of high demand used Prii sold for above list price). According to the link below, Prius total cost of ownership is below other comparable vehicles.

And of course the life-cycle advantages of hybrid technology are well documented.
In addition, conventional brakes work by heating up and abrading asbestos like brake shoes which shower particulates around roads, while hybrids use electromagnetic braking with no physical contact and no particulates emitted. This difference is no small economic impact, given the very serious documented effects of particulates on human health and mortality, especially cardiovascular impacts.

Motorcycles > Priuses, and you have to go through a big hassle to get licensing to drive them.

" How many SUV purchases are practical, how many sports cars, how many luxury sedans? "

Most SUVs are practical, as are most luxury sedans.

What's objectionable about Prius's are all the official benefits offered. Their advantages don't merit it.

A lane-splitting moto commute teaches you about driving; passing thousands of cars gives you the birds eye view of their behavior. #1 among slow drivers are people who are texting, they also swerve. Old pick-ups driven by landscapers are #2. Prius's belong in the next group, but they more than #1 and #2 populate the passing lane where slowness is like a rock in the river, causing frothiness when flowing traffic moves around it. Their silence in parking lots is kind of dangerous, too.

I know it will be a slow driver when I see a Buick.

Sorry, I'm new to this site but have so far found it to be a pretty insightful place... but I don't understand the purpose of this post or the quotation itself.

I haven't read the book, but my guess is this has something to do with hybrids being able to use the car pool lane, which has been the policy here in California for several years. Presumably this allowance was put in place to encourage hybrid ownership. The argument against this policy is that it undermines the point of car pool lanes, which are supposed to reduce congestion by lowering the number of vehicles on the road.

I feel that is a very fair criticism. Hybrid's are a good development but the HOV lane privileges should be revoked.

How is a Prius different than a personal computer circa 1960 or 1965? And yes, personal computers were available in 1960 and 1965, Ken Olsen formed DEC in 1957 with the goal of building personal computers, the first was the PDP-1 and the major breakthrough was the PDP-8.

Very few of them resulted in "money saving" but provided a high status way of attracting employees and students and they bridged the way to the world we have today.

The logic arguing against the Prius if applied to personal computers would be no one should have bought one until the year 2000 or maybe 2010, and certainly not in the 60s, but without the PDP-1 and others of its ilk, who would have imagined computer games, like Pong, sold in 1972?

And the government spent most of the money on computers until sometime in the 60s, maybe 70s.

The difference is that people using an abacus or log table in 1965 weren't taxed extra and the money used to subsidize the people who had bought a PC.
(HOV lanes, Hybrid only parking spaces)

I feel hybrids would retain most of their following even without the gimmicks of special parking spots etc.; such gimmicks actually do the hybrid cause a great disservice. They aren't so common to make much of a difference to a hybrid driver's convenience but OTOH evoke a lot of anti-hybrid resentment (rightly so).

I don't have anything to say about the ridiculous "sentence of the day". However, I bought a prius about a month ago and I couldn't be happier. I don't feel cool in it that's for sure. I'm actually a little embarassed. I also don't care one iota about the environment. The sun could explode next week for all I care. I live in a part of the country that doesn't have hybrid only parking places, and I don't even know what HOV stands for. I wasn't going green when I bought the car. I guess you could say I was going for the green. I cut my fuel bill by more than half, and did I mention it's the perfect car for smug pricks? I think you all would look great in one!

This shows which they last very much lengthier and thus saving you income which could otherwise are actually utilized to purchase new ones.

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