I have been reading negative reports about Prius mileage and cost effectiveness for years. Here is one called "The Hybrid Hoax," written about a year ago. The author propagates misinformation by referring us to another article written in 2004 by a USA Today reporter (Kiley) who drove a Jetta diesel from Detroit to Washington, D.C., and a Prius back from Washington, D.C. to Detroit:
Kiley had to stop to refill the Prius, which ended up averaging 38 miles per gallon, compared with 44 miles per gallon for the Jetta
What this idiot failed to mention is that the Prius actually got 51.7 MPG on the computer mileage gauge, which measures tire rotation and fuel flow precisely and accurately. The accuracy of the computer MPG calculation has also been verified by the EPA, which tests car emissions by measuring similar parameters. The reporter got 38 MPG when he manually checked the mileage. Toyota gave him several reasons to pick from as to why his manual MPG numbers were in error.
The bottom line is this: No Prius gets a mere 38 MPG on the highway (unless you load it up with five people, which explained away one complaint I found by a guy in five person carpool). The idea that Toyota has duped consumers by giving them a rigged mileage computer is asinine in the extreme. A Prius will go 12.5 miles on one quart. So if the amount of gas you think you put in your tank is off by just one quart you would* by enough, you could calculate an MPG of 62.5 or 37.5 instead of 50, which is just what this reporter did.
*Note to self, never post after third glass of merlot.
What would he have done if his mileage calculation had been off that day in the opposite direction? How confusing would that have been?
"What the ...? The computer shows 51.7 MPG and my calculations show 62 MPG but it still ran out of gas before the Jetta, which only got 44 MPG? My editor isn't going to like this."
Welcome to the real world Mr. Newspaper Reporter, where a real test would have put together a statistically significant number of test runs and your result would have been part of the scatter.
Here is a road trip report by a guy who hauled himself and a passenger 5,000 miles in a Prius and cross-checked the computer to the manual method. He found the manual method inconsistent, sometimes off by 10-11 MPG one way or the other, whereas the computer was consistent.
And to ice the cake, I now own a Prius and guess what? It really does average in the low fifties on the highway (without passengers). It varies a great deal in the city depending on variables like hills and the number of passengers, but we have never seen lower than 48 MPG on a tank of gas. So put that in your pipe and smoke it.
This is starting to get long, so I will address the cost effectiveness issue briefly. Since the Prius does not come in a non-hybrid version, you can't really compare it to other cars, so I will discuss the Civic instead. Some results show you will save money over the car's lifespan buying a Honda Civic Hybrid over a regular Civic, and some don't, as usual depending on your choice of assumptions.
It is a moot point because in both scenarios, the amount of money involved when spread out over the life of a car is trivial. Anyone who buys a hybrid Civic purely to save a few hundred or thousand bucks over the car's lifespan has not done his or her homework. Few people buy a Civic to save money. They buy it because they like it for all kinds of reasons. If you want to minimize car expenditures, buy a cheap economy car and live with the lower status and reliability. Buying a hybrid version of the Civic (like opting for a power everything, automatic transmission, and leather interior package) will give you greater prestige for that extra money, not to mention you will truly use a lot less gas.
The beauty of the hybrid package is that it will eventually offset all or most of the premium you paid for the status associated with the hybrid logo. I know several wealthy individuals who have traded their luxury car for a Prius. The question now becomes, will a Prius produce less CO2 than a Hummer on a life cycle basis? Sorry, this article is too long already. Stay tuned, you haven't seen anything yet.
Comments
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spaceshaper Posted 10:26 pm
19 Jan 2007
Here's the bottom line: a Prius is not better, just a teensy bit less worse. Just as with any other car, every mile driven in a hybrid accelerates global warming. Gotta figure out how to drive less, people. Much less.
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sunflower Posted 11:21 pm
19 Jan 2007
So we purchased a Prius from the first shipment in 2000. We kept a mileage and gas log for two years. The car computer was very accurate. We found that weather was the largest variable. Heavy rain meant 41 mpg and on a warm dry day we could get up to 61 mpg. Number of passengers, driver style, and type of roads mattered, but not as much as weather.
Your are correct, the Prius is a very cool car. Cassandra is looking forward to a plug-in retrofit from Toyota.
Carpools and lower speed limits will save much more carbon than hybrids, and at zero capital cost. We need leadership.
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Erik Hoffner Posted 11:32 pm
19 Jan 2007
http://www.orionsociety.org/ogn
Toll free: 888/909-6568
187 Main Street,
Great Barrington, MA 01230
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spaceshaper Posted 12:12 am
20 Jan 2007
We also need to design and build more compact communities, to live closer to our jobs, our grocery stores, and our kids' schools, we need to stay home more, limit our interstate trips, not make our cars the linchpin of our lives whether they're hybrid or conventional, and not assume it's our birthright to lead an urban lifestyle from the deeper recesses of exurbia. And the leadership for all of that is local and personal.
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Biodiversivist Posted 1:37 am
20 Jan 2007
Small turbo charged diesels also get great mileage as I pointed out here. They are seen by some as an even better status symbol than a hybrid, especially if you burn biodiesel in them. Now that clean diesel is available I hope to see diesel cars with air pollution devices in the next few years. Volkswagen apparently has decided not to sell the Jetta, Golf, and Beetle in the U.S. this year because they can't meet air pollution standards.
Also note that the Texas air pollution authority is trying to get the 20 percent biodiesel blend banned because it exceeds NOx limits. Imagine how dirty B-100 must be.
Also, the climate nuetrality of biodiesel depends on what it is made from. Your supply is probably from soybeans. Different studies show on a lifecycle basis it would still add to the atmosphere somewhere between 60 and 22 pounds of CO2 for every 100 pounds released at the tail pipe .
In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world
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Steven T Posted 1:49 am
20 Jan 2007
A hybrid is a decent option for some folks; biodiesel for others. Yes, a shift to these types of cars should not distract us from aggressive attempts to create less auto-dependent communities. At the same time, it is essential that we force the auto industry (kicking and screaming if necessary) into the 21st Century.
Do we need leadership that is "local and personal"? Sure. But global warming is also an issue that demands strong national and international responses. Those responses will likely not be as far-reaching and rapid as dedicated environmentalists seek, but frankly that is typical of social-change movements.
There is no "one best way" to respond to global warming. How do we debate alternative responses without lapsing into "either-or" dead ends?
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caniscandida Posted 1:49 am
20 Jan 2007
Chickens are our cousins!
So are other sensitive animals!
Enough is enough!
No more factory farms!
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leszekp Posted 2:24 am
20 Jan 2007
Your argument that the computer mileage gauge is somehow more accurate than that actually calculated by dividing the total mileage by gallons consumed isn't correct. Electronic sensors can be used as a general guide, but they can be thrown off by any number of factors. When the EPA says that the computer numbers are reasonable, they figure that out by averaging those numbers over a long distance, and then comparing them to the correct number, which they calculate by taking the total mileage and dividing that by the gallons consumed! That's also how they calculate the mileage in standard EPA tests - because they know there's no way to get an accurate results from standard auto electronic sensors. If the electronics give you one number for MPG, but mileage divided by gallons consumed gives you another MPG number, it's the latter number that's real, and correct.
Your argument that being a quart off on the fillup could change the MPG number calculated by 12.5 MPG is mathematically wrong. The gas tank capacity of the Prius is just shy of 12 gallons, or 48 quarts; if you're off by 1 quart, that will change the mileage calculated by 1/48, or a bit more than 2%. So, for the USA Today example, if the fillup were off by two quarts, more than the amount you state, it would still only affect the MPG calculated by less than 1 MPG, not the 12.5 you claim.
You may well average in the 50s for your Prius driving, and that's great, but you are the exception rather than the rule. For standard cars, the EPA reports that most people get about 14% poorer mileage than the sticker numbers, but they report that people get about 35% less than the sticker numbers for hybrids. There's a whole bunch of reasons for that, including the need to keep a hybrid engine running at stops when you're using either the A/C in summer, or the heater and defroster in the wintertime. Driving from Detroit to Washington in June, as the USA Today guy did, he was probably using his A/C, which certainly had an impact. That's one of the reasons the EPA will be changing their MPG testing procedures shortly - the old ones didn't take A/C, defroster, heater, low temperatures, hilly conditions, etc. into account, and gave a value higher than what most people get. Yes, you can meet or beat EPA numbers if you drive right, or in the right conditions - I get 15% better average mileage than the EPA numbers in fairly challenging conditions (cold weather, hilly terrain). But you judge typical mileage by the average, not the exceptional.
After badmouthing the USA Today argument that the Prius might not make sense from a financial standpoint, you then segue into an argument that financial issues don't matter, that a few hundred, or a few thousand, dollars over the lifetime of a car isn't going to make a difference to most people, and that people should buy a hybrid as a status symbol. Boy, that frosts me! First off, I'm not going to pay hundreds or thousands of dollars for a status symbol, especially if the environmental benefits aren't as good as advertised; I'll put the money into things like better insulation for my house, a new furnace, fluorescent light bulbs, etc., items that have the potential to save far more energy than any hybrid. Secondly, how is spending more to buy a hybrid as a "status symbol" that much different philosophically than buying a Hummer, or Ferrari as a status symbol? You're not doing it because it benefits the environment, you're doing it because you think the people will see you driving the car and be impressed because it's "cool", it's "trendy". That's consumption for consumption's sake, and I thought we wanted to move past that kind of lifestyle. I especially dislike this attitude in the celebrity environmental enthusiasts like Laurie David, who make a fetish of driving a Prius, but otherwise live a lifestyle of significant consumption and multiple McMansions that collectively consume far more energy than any potential savings from driving a Prius.
Hybrids are a useful first step towards environmentally-sustainable personal transportation, and I'm glad they're there. But overselling their advantages, and ignoring reality because it doesn't jibe with your philosophy, doesn't do anyone any good at all.
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David Roberts Posted 2:33 am
20 Jan 2007
Yeah, who would ever do that?!
www.grist.org
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econoclast Posted 2:40 am
20 Jan 2007
EPA mileage estimates for all automobiles are misleading. The EPA obtains these estimates by running a car on a treadmill at 45 MPH w/o AC, stereo etc.
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amazingdrx Posted 2:57 am
20 Jan 2007
That puts the plugin Prius mileage average well over 200 mpg. Clearly beating the diesel or any other comparable internal combustion vehicle.
Calcars or some other group will most likely come out with a plugin kit long before Toyota does it officially. Why is that?
I think Toyota (and other foreign companies)is being bullied by the Cheney administration. Threatened with trade barriers if they do not delay any release of a plugin vehicle.
http://amazngdrx.blogharbor.com/blog
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leszekp Posted 3:56 am
20 Jan 2007
Is this a socially or environmentally responsible way to spend your money?
Is it more important to show the world that you're someone that cares about the environment, or to actually be someone who cares about the environment?
Does it do any good to ignore or disparage the facts if they conflict with your preconceptions, even if your heart is in the right place? Hybrids are overall a good thing, but overhyping their attributes is not.
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sunflower Posted 5:31 am
20 Jan 2007
There is much more to the Prius than the battery. These cars are well engineered, carefully manufactured, and are very reliable. Our original Prius continues to appreciate in resale value, unheard of excepting exceptional vehicles. I recommend this car beyond just gas mileage. And it is sexy.
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Tod Posted 6:34 am
20 Jan 2007
"Because the world doesn't matter if you don't have the strength to go ahead and choose something that's really true." - Julio Cortazar, Hopscotch
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David Roberts Posted 7:16 am
20 Jan 2007
www.grist.org
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willa Posted 9:57 am
20 Jan 2007
As for killing the mileage on a Prius: Driving back and forth to feed my horses is freakin' killing me, especially when it's cold. It's only a few miles, so the car barely has a chance to get warmed up, and something about the specific arrangment of hills and turns seems designed to cause the car to get the worst mileage possible anyway. I've barely driven anywhere else in the last few weeks, so the average is now--gasp!--down below 40. I'm so embarrassed!
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Biodiversivist Posted 12:31 pm
20 Jan 2007
In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world
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Biodiversivist Posted 3:40 pm
20 Jan 2007
http://www.hybridcars.com/gas-saving-tips/maximizing-mile...
Take what it says with a big grain of salt. If the following were true, the Prius would be the first ever perpetual motion machine:
"Don't be concerned about hills, especially routes with short steep uphills and long gradual downhills. The glide or coast on the way down--especially if it's uninterrupted--will more than make up for the extra energy to get to the top. And the downhill stretches will give you a chance to recharge your battery through regenerative braking."
In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world
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ErikB Posted 4:18 pm
20 Jan 2007
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Erik Hoffner Posted 12:10 am
21 Jan 2007
But my real point is this: I can't afford a Prius. Period. Not even a used one.
If you want to do the right thing, have to drive a car, and have the typical salary of the non-profit activist, you have to look hard at a used diesel. And enjoy your 50 mpgs.
The Orion Grassroots Network is a meeting place for 1000+ great grassroots organizations working for conservation and more: http://www.orionsociety.org/ogn
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sunflower Posted 12:17 am
21 Jan 2007
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Nucbuddy Posted 12:46 am
21 Jan 2007
Life of soot:
http://www.google.com/search?q=diesel+pollution
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donee Posted 1:01 am
21 Jan 2007
I have been looking at the hybrid thing for years. I had a seminar in college back in the late seventies about Hybrid cars. One of the electrical engineering professors got a Vega with a blown engine from GM, and made a series hybrid with a Yamaha motorcycle engine from it. This got me interested.
Hybrids are ideal slow and go vehicles of the mass produced vehicles sold right now. Slow and Go is kinda like the EPA City test, which is more like suburban real life driving, than metropolitan inner city.
So, testing a Hybrid against the most common and developed over-the-road mileage technology of the turbo-diesel (most 18 wheel truck tractors are turbo-diesel, some even compounded turbos) is not going to be an even match.
Even so, the Prius did alright, as detailed above. And considering that the Prius was using a fuel with only 88 % of the energy content the Jetta was using, the Prius actually won.
As I remember when I read this test originally, the test was done in the spring between Detroit and Washington DC. The Jetta was driven to Washington DC, and the Prius back. Now any of you Bonneville "Speed Week" guys will spot the test methodology flaw right off. For the test to be legitemate, both vehicles will need to go both ways, just like they do for speed runs. Since the test was in the spring, when there are strong prevailing east to west winds, the Prius was setup. It was probably bucking head winds all the way back from D.C.
A properly run test was done by Mercedes. They took Turbo-Diesel SUV, and a Lexus Hybrid Synergy Drive SUV(same system as the Prius) and drove them a few hundred yards apart down the same roads at the same time. In the end, the Turbo-Diesel SUV edged out the Lexus in mileage. But in energy consumption the Lexus edged out the Mercedes Turbo-Diesel (which has a claimed 45 % effiency engine). So, this shows the value a systems approach to designing a vehicle, rather than a component centric approach.
After reading the about the Mercedes Test, that convinced me the Hybrid Synergy Drive technology had matured to the point where it was yielding similar operational efficiency to the turbo-Diesel. And the HSD brakes last nearly forever, and HSD does not have alternator, engine starter or bands in the automatic transmission to ware out. So I went out and bought a Prius.
Now as to global warming, I hold out hopes for Biobutanol. Butanol can be made from similar bio feedstocks as Ethanol, can be stored and transported in existing gasoline infratructure, has nearly the same energy content and similar octane to gasoline, and can thus be used as a high fraction of present day vehicle fuel. The processing is similar to bio-ethanol (a differnent bateria is used than yeast for ethanol), but you end up with a product with allot more energy per gallon processed.
I like the idea of a Diesel, but I have been behind so many different sulfur spewing and particulant laden exhaust black stained diesel cars (Jetta's, Pasats's, Mercedes E series!) that I just do not want to join that club. Better diesels are on the way in 2008 we hear, from Honda, VW and possibly DiamlerChrysler. If you need a panel van, its hard to beat the Dodge Sprinter turbo-diesel right now.
In my daily driving I can spot by smell up to a half mile ahead two types of cars. 1980's GM V8's with suken carborteur floats, and VW diesels.
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Erik Hoffner Posted 1:55 am
21 Jan 2007
"B100 has shown about a 50% reduction in particulate matter (PM or soot) emissions."
http://www.ucsusa.org/clean_vehicles/big_rig_cleanup/biod...
I'm not interested in seeing more people drive diesel cars unless they're using biofuel.
The Orion Grassroots Network is a meeting place for 1000+ great grassroots organizations working for conservation and more: http://www.orionsociety.org/ogn
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Nucbuddy Posted 2:30 am
21 Jan 2007
When it comes to buying a new car, gasoline-powered models are better than diesels on toxic soot and smog-forming emissions. The downside to current diesels is that they produce 10 to 20 times more toxic particulates than their gasoline counterparts, more than can be made up for with the use of biodiesel. Diesels fair even worse when it comes to smog-forming nitrogen oxide emissions, with greater than 20 times the emissions of a comparable gasoline vehicle.
Half of 20 times the pollution levels is 10 times the pollution levels.
Biodiesel. It's totally killer.
ncbi.nlm.nih.gov/entrez/query.fcgi?CMD=search&DB=pubmed&term=biodiesel+toxic
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amazingdrx Posted 3:10 am
21 Jan 2007
I think utility rate structure reform that encourages investment in distributed renewable generation and storage might make this possible. The coop could pool small investments by consuming members with subsidies to provide low interest loans for members who install renewable energy systems.
Eventually as standard generating plants are no longer needed, coops could aquire the majority share in local utilities and buy them out.
Another great feature for coops would be conversion of standard vehicles to plugin serial hybrid that then could be leased to members. some long term leases and some just for a few hours when someone needs a vehicle only ocasionally.
http://amazngdrx.blogharbor.com/blog
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Nucbuddy Posted 3:54 am
21 Jan 2007
If standard generating plants were no longer around, how would wind and solar mining machinery be manufactured?
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Biodiversivist Posted 4:19 am
21 Jan 2007
You spent a lot of time explaining why real world mileage varies so much from the EPA ratings, but let me point out that my original post has nothing to do with that topic. That would make an interesting subject though.
When the EPA says that the computer numbers are reasonable, they figure that out by averaging those numbers over a long distance, and then comparing them to the correct number, which they calculate by taking the total mileage and dividing that by the gallons consumed! That's also how they calculate the mileage in standard EPA tests - because they know there's no way to get an accurate results from standard auto electronic sensors.
Actually, not. The cars are run on a dynamometer and the carbon content of the exhaust is measured with an electronic sensor. That measurement is later converted to fuel flow with a math formula. The test stand odometer reading is then divided by that fuel flow to get MPG. The test driver accelerates, brakes, and idles the car according to a prescribed routine where the average city speed is about 20 miles an hour. The city driving test cycle simulates an 11-mile, stop-and-go trip that takes 31 minutes and has 23 stops. About 18 percent of the time is spent idling, simulating stop and go traffic at rush hour.
The highway mileage is obtained by driving the car (on its dynamometer) 10 miles, with a maximum speed of 60 mph and no stops, in total, averaging 48 mph.
And trust me, if you get in your Prius and go outside and simulate the EPA simulation, you will get the same results on your car computer within a few percent one way or the other.
The electronic sensors measure fuel consumed and tire rotation very accurately. If you were to measure how much fuel is missing from the tank at the end of the test, and divided it into the odometer reading, you would get the exact same MPG. And, if you were to compare what the EPA had measured to what the Prius computer measured, they would be within a few percent of each other. Why is that? Well, first, because the Prius odometer reading will read to within a few percent of the test stand, and since the gas mileage calculation involves only two variables, that leaves the fuel flow rate. The Prius measures flow at the fuel injectors and gets results that are also within a few percent of the EPA measurement using carbon in the exhaust.
If you manually calculate your mileage you are also relying on other electronic sensors in the fuel pump to tell you how much gas you put in--a flow meter hooked to a transducer hooked to a digital read out.
You may well average in the 50s for your Prius driving, and that's great, but you are the exception rather than the rule.
I believe I said that we have yet to average less than 48 for a tank of gas and get in the low 50's on the highway. Note on the link I reference that the Prius is averaging 48 MPG for a sample size of 1,016 cars with a standard error of 0.1, and that is not just for highway miles. So, saying that I am the exception was not very ...ah, accurate. I am in fact, the rule. City driving, as all new Prius drivers quickly realize, is where you get the lowest mileage. Since most of our miles are on the highway, our average tends to stay high. If we drove exclusively in the city it would be much lower. Even Consumer Reports gives the Prius a 50 MPG highway rating.
The USA article is typical of what is so wrong with traditional print media. My blog post had a glaring alcohol induced screw up (and if I hadn't caught it, a commenter would have and in fact did) and it was easy to rectify. Here is the comment from the USA article that made it all crystal clear to me:
The gas-tank warning light flashed after 422 miles. I drove 10 miles to the next gas station and filled up, putting 11.1 gallons into the 11.9-gallon tank. That would indicate 38 mpg, far short of the 51 mpg government rating. The car's trip computer told me it had been getting 51.7 mpg.
If that 51.7 reading was the average for the 422 miles he just drove, then that was his real mileage, regardless of road conditions, air conditioning use, or headwinds.
I have calculated my car's mileage by hand only twice. Both times it came out very close to the computer, one high, one low, so I quit doing it. You don't really think Toyota is trying to hoodwink half a million Prius drivers do you? Logically and statistically, the 38-MPG calculation was the one in error. How he screwed up will never be known. The ways he could have screwed up are many.
After badmouthing the USA Today argument that the Prius might not make sense from a financial standpoint, you then segue into an argument that financial issues don't matter, that a few hundred, or a few thousand, dollars over the lifetime of a car isn't going to make a difference to most people
Let's run some math. You pay 26K for your Prius instead of, say 14K for a, let's say, a Scion, and save, lets say 1K over ten years. That is 100 dollars saved per year, or $8.30 per month. If you save 2K, that's $16.30 per month and so on.
Secondly, how is spending more to buy a hybrid as a "status symbol" that much different philosophically than buying a Hummer, or Ferrari as a status symbol?
Uh, the Prius releases from its tail pipe five times less CO2 into the atmosphere than the Hummer?
You're not doing it because it benefits the environment, you're doing it because you think the people will see you driving the car and be impressed because it's "cool", it's "trendy".
Wrong. Most do it for both reasons. People are replacing their gas-guzzlers with a Prius for both reasons. High gas mileage alone doesn't cross the purchase threshold. That is why so many rich people are trading in their gas guzzling luxury cars for a Prius but are not so tempted by a Chevy Aveo ($11,000). Why they go for a high mileage car isn't what matters. The fact that they do is what matters.
In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world
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ottavio Posted 4:59 am
21 Jan 2007
My partner, however, is not as lucky. She works in a neighboring town and has a 30 mile round trip daily commute, because our local mass transit district would be a joke in most Third World countries. She carpools, which helps. We are now on our second Civic hybrid, which we bought specifically for her commuting needs.
Our mileage experience echoes what a number of posters have reported: the difference between what the computer told us and what our hand computations revealed varied plus or minus 10 percent.
But I wanted to add one twist to the discussion about the overall cost of owning a hybrid, which is always conveniently left out of the hybrid-bashing articles I've read in the mainstream press: tax credits.
Our experience with our first Civic hybrid is illustrative. We purchased the car new in 2003 for $19,300. The state and federal tax credits reduced our out-of-pocket costs to $15,800, which made the price only slightly higher than a standard Civic. We drove the car for three years (35,000 miles), and decided to get the redesigned Civic hybrid in 2006. We sold the 2003 hybrid in short order for $17,900, which was $100 under Kelley Blue Book.
So we purchased a new car, drove it for three years, and sold it for $1,400 more than we paid for it (factoring in tax credits).
Of course not every state has tax credits, and the status of federal hybrid tax credits under the Bush Administration is sketchy at best, but they do exist. Yet I still have to wonder why all these "real world" hybrid cost analyses fail to mention them.
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donee Posted 7:11 am
21 Jan 2007
Your comments are ignorant of a basic fact about the Prius. It has a low emission gas tank, which colapses as the fuel leaves the tank. Yes, that is right, its rubber lined. Now rubber changes size with temperature. In my Prius owning experience the change is most apparent filling up at 20 F in the morning, and then filling up at 55 F on a sunny afternoon. The difference for the 11.9 gallon tank is about 1 gallon between these two situations. How is the amount of gas pumped going to be anything close to accurate for the purpose of a mileage test?
Being rubber, it also stretches depending on the back pressure needed for the gas pump to click-off. Unless the fill-ups were at the same pump, the pump measured gas volume is going to be inaccurate for a mileage test purpose.
Additionally, several Prius drivers who have done long term pumped gas/ mileage display computed gas consumtion comparisons, and invariably the results are within 1 to 2 percent - the legislated accuracy of gas pump. But, looking at the data, there can be a 10 or even more MPG variation between that tank's pumped gas computed mileage and the computer mileage. This variation is my experience too. It was especially variable when the car was less than 6 months old, presumably due to the rubber mechanical memory. As it takes me two weeks to burn through 9.5 gallons in my Prius, the tanking temperature can be quite different too.
VOC's, such as vaporized gasoline are the catalytic agent in air which causes carbon monoxide, NOx and unburned HC to transform into Smog, and the highly reactive Ozone component of Smog. Its a shame unscrupolous, or ignorant journalists would have that worthy feature cause a misperception of the Prius capability.
Also, the EPA does not measure gasoline consumption by the volume of the gasoline pumped into the vehicle. This is not accurate as gasoline changes volume with temperature. They actually, get this, collect ALL the tail pipe emissions, and measure the number of molecules of the combustion products to determine how many gallons of gas were burned. Clearly this is the laboratory standard method.
The USA today article was obviously a faulty evaluation to any engineer/test technician/scientist. My opinion is that it was a outright setup to make the Prius look bad. And even in trying to make the Prius look bad they screwed up.
As to the average/peak comment, take a look at http://www.greenhybrid.com web site. There are year round AVERAGE car mileage reports on that site for a variety of vehicles including the Prius. The 1017 reporting Prius drivers indicate a real-world average of 47.5 mpg, with a range from 45 to 50.4 mpg. Let's see, 47.5 compared to 55, umm, why that is 13.6 % less than the EPA combined for the Prius. Very close to what you claim the EPA says is the the typical difference for non-hybrid cars (14 %), and WELL above what you say the EPA claims for hybrids (35 %). In a Prius, that 35 % down would be 35.8 mpg. To anybody who drives a Prius doing less than a sustained 90 mph, or in temperatures warmer than 0 F, the EPA comment is laughable.
Why are "car" people so anti-Prius? I think it comes down to a few reasons. It handles dangerously, stock. Allot like an SUV actually. There are ready modifications to fix that however, developed by a guy who preps racing Corvettes. Allot of car people who are tasked with evaluating a car in a week, do not have the time to conclusively figure out the problem.
It takes a while to learn how to drive. With a standard car the car evaluator has years of experience, with the Hybrid Synergy Drive, its a little like being 16 again, only without the Driver's Ed teacher in the next seat over.
These things result in a bad first impression. I had it too, admittedly. But I studied up on the car for some months, and cleared each issue I had in my head.
The media car evaluator only has 3 days with the car and a deadline. "How dare Toyota give me something to do in three days that takes six months? "
The end result is the media car evaluator either references stuff from on-line, from other media guys in the same boat, or write a negative reveiw. They come to form a "if this is the future, I want no part of it" attitude.
And with all the shenanagins going on out there by the counter-marketing offices at the Big Three, the result is just one big confusion. This is dying away now as the big Three now ready their own blank-sheet 21st century cars. And guess what? These are hybrids cars (some with other kinds of prime movers). Even the Fuel Cell cars are being hybridized to make reduce the required Fuel Cell size/cost.
The people with Prius's love the cars on whole. This is why it was rated right up there with the Corvette in customer satisfaction (first and second in 2005).
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Nucbuddy Posted 7:24 am
21 Jan 2007
...Which might be thought strange, considering that...
http://epa.gov/fueleconomy/420f04053.htm
After the vehicles have been tested, the results are adjusted downward to account for conditions that occur on the road that can affect fuel economy which don't occur during laboratory testing, such as cold temperature, aggressive driving, excessive use of power-hungry accessories, among others. The city is adjusted downward by 10 percent, and the highway by 22 percent.
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sjg Posted 9:37 am
21 Jan 2007
I am also a hybrid car owner, of a 2003 Civic with manual
transmission. I have some arguments with the initial post (thank you
leszekp), but I also agree with a lot of what has been said here. The
EPA is not some cheat. I have actually exceeded their highway estimate
with my overall mileage, and I do drive under adverse conditions some of
the time (in the city, below zero temperatures, snowstorms, mountain
passes, short trips and excessive speeds). I average 52 miles per
gallon over 66 tanks, when the car is only supposed to get 51 on the
highway. Individual tanks vary from 42 to 60 mpg, manual method, and
the trip odometer usually reads about 4 mpg higher than that. I agree
that individual gas purchases (shut-off valve, temperature, etc) can
cause inaccuracies, but I really do think that the manual method is the
accurate one when you average many tanks. The miles are the same in any
case, and the gas pumps are required to deliver gas accurately, so I
don't think they could all have the same bias. I get good mileage
because I drive rural highways at very modest speeds and I use the
cruise control most of the time. I keep the tires at 40 PSI, and I
don't run the A/C often.
I purchased the Civic because I wanted a car that handled well and got
good highway mileage (in 2003 the Prius didn't rate quite so well). I
also didn't want to make a fashion statement, it's just not my style. I
don't like extra blinky lights on the dash to distract me. I do not
think we as environmentalists should get huffy about fashion statements.
It's a wonderful thing that the Prius has become so trendy, because it
will result in less pollution and more fuel being saved. I also think
it's silly to disparage hybrids as being not the single best choice.
There are dozens of ways to reduce our environmental impact, and they
are not equally relevent to the diversity of people who read the Grist.
I couldn't get such good mileage if I didn't ride my bike to work every
day. Almost all conservation isn't an either/or proposition. I also
have a solar powered and solar heated house. I am fortunate to be able
to afford these things. Part of that fortune I created myself by living
carefully, and having no children. The Civic replaced a 1982 Subaru
that I had reupholstered by hand, and painted after fixing the rust. My
husband drives a 1983 Subaru when he drives at all. Our solar house is
also a mobile home.
My Honda got us an $1815 Colorado HEV tax credit, supposedly 75% of the
price difference. We also got a $2000 tax deduction. Without those it
cost about $2420 more. It gets 52 miles per gallon, and a regular Civic
gets about 38 miles per gallon. That's a 27% fuel savings. The regular
Civic might be expected to use about 2631 gallons in a 100K lifetime.
The hybrid Civic would use 1923 gallons, a savings of about 708 gallons.
Without any tax breaks, the break-even gas price is $3.42 a gallon. The
tax deduction saved us about $500. Including the deduction but not the
credit our break-even gas price is $2.71, and with the tax credit and
the deduction the break-even gas price is 15 cents a gallon. Clearly we
made money on the purchase, but we would not have lost much, even
without the tax credit. I love my car and would have chosen it even if
it were not a money-maker.
Cheers,
Susanna
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Erik Hoffner Posted 10:01 am
21 Jan 2007
Boy do you hate particulates. So I have another burning (har har) question for you. Would you prefer that I stop heating my home with the carbon neutral wood I cut from my woodlot here, or just let the backup "clean burning" forced air propane heater come on? I mean, it's clean so far as THIS guy can tell. Don't ask my neighbors, they don't care, they all have woodstoves too. Just interested in your opinion. Sincerely,
A Little Sooty
The Orion Grassroots Network is a meeting place for 1000+ great grassroots organizations working for conservation and more: http://www.orionsociety.org/ogn
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Erik Hoffner Posted 10:10 am
21 Jan 2007
The Orion Grassroots Network is a meeting place for 1000+ great grassroots organizations working for conservation and more: http://www.orionsociety.org/ogn
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willa Posted 10:51 am
21 Jan 2007
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Laurence Aurbach Posted 10:56 am
21 Jan 2007
An advanced, efficient woodstove used in a low-density, rural wooded area is probably not a problem. Extra fine particulates emitted by thousands of vehicles on heavily-traveled expressways running through residential areas is a big problem.
Particulates near heavily traveled routes are responsible for hundreds of deaths per year in every large city; particulates lead to greater chances of cardiac or pulmonary disease; excess particulates from vehicles make childhood asthma two and a half times more likely.
Here are some sources you can check out:
Clearing the Air: How epidemiology, engineering, and experiment finger fine particles as airborne killers
Ultrafine Particles: The Science, Technology, and Policy Issues SCAQMD Conference
And, for Massachussetts residents: Somerville Transportation Equity Partnership
I also have an annotated bibliography of 28 scholarly studies I can send to you if you'd like to research this topic in more detail.
On a related note, ten years ago Sen. John Dingell was one of the leading opponents of higher EPA standards on particulates. Dingell characterized the research by saying, "In point of fact, the scientific record is unambiguously ambiguous." The language is almost identical to the current stonewalling on efficiency standards and CO2 regulation.
Another note: Your woodburning stove is only carbon-neutral if you are growing wood just as fast as you are burning it. I'm sure you knew that already.
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spaceshaper Posted 11:05 am
21 Jan 2007
This has to be one of the most commented threads in recent Grist history. Can someone tell me why marginal improvements in what is inherently a highly problematic technology attract so much attention in the community of environmental activism, while infrastructure adjustments that could provide far more profound benefits attract so little? Could it be because the Prius is a nice shiny consumer product that we can just go out and buy (providing of course we have the moolah), and infrastructure changes actually require concerted long-term community effort?
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JMG Posted 11:11 am
21 Jan 2007
The private auto is the problem, and its days are numbered, no matter what it's fueled with.
The more energy that enviros spend trying to prop it up with slightly-less-bad-alternatives, the more the needed shift towards relocalization and mass transit/rail is stymied.
Here's an analogy that ought to be on every SAT:
Prius:environmentalism ::
"low tar cigarettes":health
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Erik Hoffner Posted 11:20 am
21 Jan 2007
Yep. I've got 7 acres of early secondary forest and it's got issues.
Anyhoo, I'm with spaceshaper. Splitting these hairs over a few individuals' choices is a waste. The big picture of what we can envision going forward is the big thing. No one I know that owns a biodiesel car will argue with me that their vehicle is the future we're looking at: it's just a bridge to a better place.
The Orion Grassroots Network is a meeting place for 1000+ great grassroots organizations working for conservation and more: http://www.orionsociety.org/ogn
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thollandpe Posted 11:31 am
21 Jan 2007
Next, consider that the GENIUS of hybrid drive is recovering the braking energy and using it for propulsion. Now wouldn't that be great to do with a VW TDI? How about NASCAR or Formula 1? To capture and use a significant source of energy that is currently being wasted (as heat) is the real advance, and for that Toyota should be applauded.
I also have access to a Honda Civic Hybrid fleet car, and have gotten 49-51 mpg. That feels great, certainly as much fun as 4WD or heated seats, and nobody asks what the payback is for those trinkets.
Who cares if a VW TDI gets better mileage . . . they're both great cars with efficiency that should embarrass most others on the road. The vee-dub diesel may take the cake with mileage and range, but the hybrid's trick is tapping a free and heretofore wasted energy source.
Toad the 12 sprocket
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thollandpe Posted 11:53 am
21 Jan 2007
Same conclusion, one additional comment. How about hybrid synergy drive for my bicycle?
Toad the 12 sprocket
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amazingdrx Posted 2:03 am
22 Jan 2007
Wisconsin has a long tradition of coops, that might help here. I think reforming the utility rate structure towards distributed renewable storage and generation is a must.
I'm thinking referendum on the '08 ballot here. A lot of progressive states could do this.
http://amazngdrx.blogharbor.com/blog
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amazingdrx Posted 2:20 am
22 Jan 2007
Coop members get a rebate, say 1 cent per kwh from the coop in return for their membership fee. The coop helps fund individual systems for members with low interest loans from the membership fees.
The extra 5 cents the individual homeowner with the solar panel or wind system gets goes to pay the loan down.
http://amazngdrx.blogharbor.com/blog
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leszekp Posted 3:47 am
22 Jan 2007
You are correct - read the wrong reference (and can't blame alcohol). But the quality and calibration of the EPA sensors is going to be of a much higher caliber than that of a standard off-the-showroom floor. That's why Consumer Reports uses actual gas consumption instead of the vehicle's sensor data to calculate the true MPG. If the sensor numbers don't agree with the actual mileage/gas consumption numbers, the sensor numbers are wrong. Reality always trumps any measurement of reality.
Here's a link to a guy who monitored both his electronic mileage, and fuel consumption mileage, over several years for his 1st-generation and 2nd-generation Priuses, and found that the electronic mileage consistently overstated his true mileage (about 5%, averaged over time).
http://john1701a.com/prius/prius-data11.htm
"And trust me, if you get in your Prius and go outside and simulate the EPA simulation, you will get the same results on your car computer within a few percent one way or the other."
Uh, this is a meaningless statement - the test is not representative of true driving conditions, and there's no way to do this test in the real world, which is why the EPA is finally changing its test conditions. The testing conditions are a climate-controlled facility, no A/C, defroster or heater on, on a dynamometer so there's no hills either. Then the results are modified based on 1980s data to try and compensate for real world effects - the city mileage is decreased from its test value by 10%, the highway by 22%. And even these aren't enough - the EPA says that on average, people get about 14% lower overall mileage than the sticker numbers, and you can get as much as 25% less without there being anything significantly wrong with the car. Yes, you can get better numbers by changing your driving style - I get about 15% better combined mileage in my car than the EPA sticker values because I drive the right way. I wish everyone would drive the right way, but they won't. It's the real-world numbers that matter, not what people might be able to achieve if they drove the right way.
For that matter, the Prius's sensors and measurement system are different than that used by the EPA, so you have no basis for saying that you'll get the same numbers.
"Note on the link I reference that the Prius is averaging 48 MPG for a sample size of 1,016 cars with a standard error of 0.1, and that is not just for highway miles."
That's not unreasonable. However, in order to determine whether these numbers accurately reflect the true mileage, you would have to know:
The mix of city/highway driving percentages
The conditions under which the driving are done
Most importantly, is this a representative sample? In other words, if you post your mileage at greenhybrid.com, are you a representative driver, or are your numbers skewed too high, or too low?
I don't know the answers to these question, but then neither do you.
"City driving, as all new Prius drivers quickly realize, is where you get the lowest mileage."
After touting the EPA tests as reliable, it's odd you'd say something like this. Based on the EPA tests for the Prius, they assign it a city MPG of 61 MPG, a highway MPG of 51 MPG, and a combined MPG (weighted harmonic average) of 55 MPG. The touted advantage of hybrids is not their improved highway mileage, but the supposed fact that they get superior mileage in city driving conditions, which account for the majority of miles driven in the US (latest figure I heard was over 60%).
"If that 51.7 reading was the average for the 422 miles he just drove, then that was his real mileage, regardless of road conditions, air conditioning use, or headwinds."
In order for that to be true, there would have had to be a 3-gallon discrepancy in his consumption numbers. That's not realistic.
"The ways he could have screwed up are many."
Uh, this isn't rocket science. Fill up in Detroit, drive, fill up again, fill up at the end, add up total mileage, divide by gallons. The onus is on you to show that he screwed up; just because you don't like his numbers doesn't mean he got it wrong.
"I have calculated my car's mileage by hand only twice. Both times it came out very close to the computer, one high, one low, so I quit doing it."
Well, I've done it hundreds of times, even set up a spreadsheet to do it automatically to track my mileage. The hand-calculated mileage does vary a lot, but you'd expect it to, and that's consistent with the results from the link above for the Prius. Your city/highway mix will change, weather conditions will change, your driving habits can change, and so on. I'd view an unvarying electronic mileage as more suspicious than a varying hand-calculated mileage.
I recall the Mythbusters episode where they looked at the effect of A/C on vs. windows open on fuel economy. Their electronic sensors showed that fuel consumption was lower with the A/C on vs. the windows open, while their actual driving test results (and those of GM and others) showed the opposite result - windows open is better than A/C on, even at highway speeds.
"Let's run some math. You pay 26K for your Prius instead of, say 14K for a, let's say, a Scion, and save, lets say 1K over ten years. That is 100 dollars saved per year, or $8.30 per month. If you save 2K, that's $16.30 per month and so on."
You need to re-think your math again. The average car in the US drives about 12,000 miles a year. Let's say the real-world MPG for the Prius is 48 MPG, and 22 MPG for the Scion. If you assume gas averages $4 a gallon over the next ten years (probably a low figure), you'll spend about $1000 a year on gas for the Prius, and about $1818 a year for gas for the Scion. If the Prius numbers are correct, you'd save about $65 a month, not the $16.30 you state. Over 10 years, that's a total of over $8000 in gas savings. If the Prius numbers are lower than that, particularly for the kind of driving you do, that could impact those savings tremendously.
But that's sort of irrelevant, because you have to figure in that you paid $12,000 more for the Prius than the Scion, not a trivial amount of money for most people. At the end of ten years, the depreciated value for both cars is going to be far lower, and the differential is going to be far less than the original $12,000. So the Prius costs you a non-trivial amount of money upfront, you save a non-trivial amount in gas cost every month, but at the end of the line you're lucky to break even financially. In terms of both money and environmental consequences, you'd be better off putting the money into efficient appliances and heating/cooling equipment, better insulation, etc..
"Uh, the Prius releases from its tail pipe five times less CO2 into the atmosphere than the Hummer?"
"People are replacing their gas-guzzlers with a Prius for both reasons."
Yeah, and a standard Honda Civic releases 3-4 times less CO2, and costs less. If you're like Laurie and Larry David, have multiple large houses at opposite ends of the country, and consume more than the average American as part of your standard lifestyle, than driving two Priuses doesn't compensate enough for your other excesses, and isn't enough to qualify you to preach to others about the dangers of CO2 and global warming. For these people, the Prius is a cloak to wear to hide their true impact on the environment from themselves and others. If you've already done everything else you can do in your home and lifestyle to cut energy consumption, then go buy yourself a hybrid and show off to the world. but if you haven't, then buying a hybrid as a sign that you care about the environment is fundamentally dishonest.
To donee:
Yes, I'm aware of the bladder, and how it can affect the gas tank volume. And yes, it is a good thing since it does reduce the VOC emission.s But this gas tank volume problem only occurs during periods of cold weather, when the bladder plastic becomes stiff and inflexible, and temperature differentials between different times of the day can be as large as your experience. The USAToday test was done in May or June, driving from Detroit to Washington DC, so the temperature effect would be minimal. In any case, the bladder effect would have to account for a 3-gallon discrepancy, and AFAIK, the most anyone has reported for this effect is one gallon, similar to what you report.
Once again: if your long-term overall mileage computed from gas consumption and distance driven differs from the electronic figures, then it's the electronic number that's wrong. Reality trumps any measurement of reality that doesn't agree with it.
"Why are "car" people so anti-Prius?"
First off, I don't know. I could guess that they see it as a threat to the concept of cars as expression of personality or power. Secondly, I'm emphatically not anti-Prius, or anti-hybrid. I think Biodiversivist's beef with the Weekly Standard and USA Today's articles is misplaced. He shouldn't be mad at the argument that hybrids get significantly lower mileage than the EPA claims; heck, he admits as much himself when he says that he gets lower mileage in city driving versus highway with his Prius, when the EPA numbers say the exact opposite. The argument he should be going after is the one in the Weekly Standard that says that the government shouldn't offer incentives for hybrid purchases and development. Long-term, hybrid, plug-in hybrid and full-electric vehicles are the only practical and sustainable solution for personal transportation. The government offers huge incentives, tax credits and deductions for non-sustainable fossil fuel technologies, which the Weekly Standard doesn't complain about - why should they now complain about far smaller financial incentives that move us in the right direction? I believe that one of the government's main roles should be to look 5, 10, 20 years down the road, see what the problems might be then, and work on encouraging technologies and behaviors that will forestall those problems.
There are also a lot of other factors in favor of the hybrid that time and space don't allow me to talk about. For example: if you argue financial savings based strictly on the current and projected future pump price of gas, hybrids have a tough time justifying their increased cost to you on a personal financial level. But the true cost of gas to you isn't the pump price: you have to figure in tax credits and deductions to oil companies, the cost of a military intended at least in part to defend access to energy supplies, pollution effects and cleanup costs, the effective cost to replace gas as a source of energy when it runs out in the future, etc.. By one estimate made about 5 years ago, when the pump price of gas was roughly $1 a gallon, the true cost per gallon of gas was anywhere from $5 to $15 a gallon. Figured that way, the government should buy everyone in the US a hybrid vehicle, and the payback time for that expenditure would be surprisingly short. But nobody figures stuff that way, even if they should - too complicated to explain, I guess.
The problem I have with evangelists for any of the alternative transportation technologies is that instead of realistically presenting the benefits, and there are many, they will exaggerate those benefits and become incredibly hostile to those that point out that they are exaggerating. Hybrid evangelists are actually pretty good in that respect. Try telling a corn ethanol enthusiast, or a biodiesel enthusiast, or a hydrogen economy enthusiast, that there are serious issues with their "solutions", and stand back to avoid getting hit by the vitriol. Ignoring reality because it conflicts with your enthusiasm for an idea, or exaggerating the benefits of a "solution", is always going to wind up being a bad idea (c.f. the neo-cons and Iraq).
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EcoSpeak Posted 4:51 am
22 Jan 2007
---
There are approx. 243,023,485 registered passenger vehicles in America today, which get around 17 miles per gallon and drive an average of 24.3 minutes to get their owners to and from work each morning. Going 55 miles per hour, that means each car is traveling approx. 22.3 miles to and from work each day.
This means an average car in America is eating up 1.3 gallons of gas each day for the commute to work.
Let's say half of the total number of registered passenger vehicles in America make this average daily commute. This would mean 157,965,265.25 gallons of gas are being consumed each day just to get Americans to and from work.
Each gallon of gas burned emits 19.4 pounds of CO2. So this means that Americans' daily commute to work emits 3,064,526,145.85 pounds of CO2 into the atmosphere. Each day.
OK, now say that by some act of god or Congress half of all registered passenger car-owning Americans switched in their current cars for hybrids and made the daily 24.3-minute commute to work each day, averaging 40 miles per gallon, a low estimate for hybrids.
Each hybrid would use just over half a gallon of gas for its commute. So each day American commuters, in their "sexy" hybrids, would expel 1,320,103,570.5 pounds of CO2 into the air, a 67% reduction.
Of course such a scenario is hardly on the horizon (I am in no way suggesting that such a scenario is possible); and even the CO2 emissions of the hybrids are a jaw-droppingly large number. But get enough individuals to make the same small change and it adds up to massive numbers.
You and I cannot control the actions of 300 million other Americans; we can only control our own actions, and our own emissions. But I suspect that most other Grist readers have to make that daily commute to work, regardless of whether or not we want to or feel bad about participating in such a wasteful system. Driving a hybrid to work at least reduces our output, since we cannot eliminate it altogether.
Agreed, the focus should be on society-wide changes, not on the miniscule habits of individual consumers. But certainly we should all do what we as individuals can do, and hope that enough of us are doing it to make a difference.
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sunflower Posted 5:06 am
22 Jan 2007
There is so much not being done. Why?
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sjg Posted 7:35 am
22 Jan 2007
I think I sort of see your analogy. Since
hybrid cars do still burn some gasoline, they
are not 100% wonderful, and therefore they are
bad, should be gotten rid of, not improved at
all. You compare them to the recreational drug
tobacco, which causes cancer. I don't think the
comparison is very apt, since all recreational
drugs are optional, and transportation is not.
I would be delighted if there were better mass
transit in the places I live, but I cannot create
it by myself. You use zero-sum reasoning too. If
I had no car I would have less energy/funds to
devote to conservation, because I would have no
job. My resources are not zero sum it's not a
choice between cars and activism. I am not an
activist and couldn't become one if I tried. It
would be completely unnatural to my personality.
I guess your choice for all of us would be to be
unemployed, so we don't consume any gasoline.
But it's not a humanly realistic choice. It is worth
thinking about what car to own if one must
own a car. Life is full of imperfect choices,
trade-offs that compete for our resources and
effort. Since a hybrid car more than pays for
itself, it cannot be accused of wasting those
resources. If I had the potential to be an
activist, owning a hybrid car would not impede
that in any way, it would get me to those rallies
cheaply and with less pollution. Similarly, if I
buy the car it lets me purchase more CF lightbulbs
than if I had not bought the car. There is no
trade-off between CFs and hybrid cars.
Cheers,
Susanna
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spaceshaper Posted 11:00 am
22 Jan 2007
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Biodiversivist Posted 11:27 am
22 Jan 2007
Uh, this is a meaningless statement, to borrow a phrase. The Consumer reports guys use a digital flow meter to "measure reality" because it is freshly calibrated and known to be accurate. Of course they don't use the Prius reading for an official test because there is a small measure of variability when you produce half a million cars. Also, the gas pump "measures reality" as well.
I went to the link you provided. I opened his lifetime spreadsheets for his 2001 and 2004 Prius. I inserted an equation at the bottom of his MPG columns (=(SUM(C4:C174))/171) and =(SUM(C4:C182))/179 and calculated the lifetime difference between his computer calculated MPG and the hand calculated one. The computer was 2% higher for the 2004 Prius and 4% for the 2001. In other words, it would show 51.2 MPG instead of 50 MPG for the 2004 and 51.9 instead of 50 for the 2001. Pretty damn good wouldn't you say? And if the tiny difference is because the computer is using three decimal places for the odometer when the manual method uses two, then the computer is actually more accurate, not that it matters, it is more than close enough and would not explain the 38/51.7 difference at all.
Uh, this is a meaningless statement - the test is not representative of true driving conditions, and there's no way to do this test in the real world
Oh contraire. If you perform the EPA test driving regimen on the Bonneville salt flats on a day that has the EPA temperature, humidity, and no wind you will obtain results that are within a percent or two of the dynamometer in the lab.
After touting the EPA tests as reliable, it's odd you'd say something like this. Based on the EPA tests for the Prius, they assign it a city MPG of 61 MPG
That is another topic as I have said before. That fact is in no way related to the accuracy of the Prius MPG calculator. You seem to have irreversibly confused the two issues. I will try one more time. If you perform that same EPA regimen on the Bonneville salt flats on a day that has the right temperature and no wind, you will find your Prius computer will calculate 61 MPG, give or take a percent or two. Now hang on to your hat because this is going to be real hard to understand, but 61 miles for every gallon is exactly the mileage the car would actually get under those conditions... do you understand that? Yes, no?
The EPA changing their test driving regimen to better reflect city driving has nothing to do with the discussion of the accuracy of the on board computer. The variables associated with city driving make it difficult to simulate. The variables on a highway are far fewer, which helps explain why the EPA and Consumer reports and the Prius computers are all within a percent or two of each other for highway mileage. City mileage will always and forever be far more variable, depending on your city, and how you drive in it.
In order for that to be true, there would have had to be a 3-gallon discrepancy in his consumption numbers. That's not realistic.
Really. What is more realistic, that he screwed up or he just happened to be driving a Prius that has a computer that's was miscalibrated to the tune of 30%? If that one Prius was miscalibrated that much then the owner will be seeing an MPG of 65 instead of 50 on typical highway trips. Again I am repeating myself. I have learned that once you start repeating the same points, your opponent has either simply stopped listening or can't comprehend what you are saying and it is time to stop.
Uh, this isn't rocket science. Fill up in Detroit, drive, fill up again, fill up at the end, add up total mileage, divide by gallons. The onus is on you to show that he screwed up; just because you don't like his numbers doesn't mean he got it wrong.
Actually, uh, I would say the onus is on you to explain why the computer decided to go bonkers that day and be off 30%. Human beings are far more prone to error than machines. Obviously, he did something wrong, like, fail to reset his trip odometer. Again, I repeat myself.
Well, I've done it hundreds of times, even set up a spreadsheet to do it automatically to track my mileage. The hand-calculated mileage does vary a lot, but you'd expect it to, and that's consistent with the results from the link above for the Prius. Your city/highway mix will change, weather conditions will change, your driving habits can change, and so on. I'd view an unvarying electronic mileage as more suspicious than a varying hand-calculated mileage.
Why don't you shared with us the results of your spreadsheet? How much is your car computer off from your calcs after hundreds of fill ups? Is it 2%-4% like the cars on the link you provided or 30 percent as in the USA article? And if it is off more than the 2%-4% maybe you need to drop in to the dealership and get recalibrated.
I recall the Mythbusters episode where they looked at the effect of A/C on vs. windows open on fuel economy. Their electronic sensors showed that fuel consumption was lower with the A/C on vs. the windows open, while their actual driving test results (and those of GM and others) showed the opposite result - windows open is better than A/C on, even at highway speeds.
This really isn't rocket science. All of those variables would be reflected in the mileage calculated by the Prius, but I repeat. You seriously don't undeerstand why that is so do you?
So the Prius costs you a non-trivial amount of money upfront, you save a non-trivial amount in gas cost every month, but at the end of the line you're lucky to break even financially
Odd, isn't that pretty much what I said in my original post?
I think Biodiversivist's beef with the Weekly Standard and USA Today's articles is misplaced. He shouldn't be mad at the argument that hybrids get significantly lower mileage than the EPA claims; heck, he admits as much himself when he says that he gets lower mileage in city driving versus highway with his Prius, when the EPA numbers say the exact opposite. The argument he should be going after is the one in the Weekly Standard that says that the government shouldn't offer incentives for hybrid purchases and development
Last time. I am not concerned at all with the fact that Prius drivers get lower mileage than those obtained with the EPA simulation. The reason for that is easy for some to understand, impossible for others. Go back through my posts and count how many times I have said that. It is just a simulation. The argument is that a Prius does not really get lower mileage than a Jetta as the articles infer, more specifically, it did not get 38 on that one trip because the computer could not have been off 30%.
I have also repeatedly criticized the government subsidization of hybrids. All that does is give ammunition to the libertarians like the one who wrote the hybrid hoax article. Life's a box of choclits
Donee,
As I just tried for the last time to explain to leszekp, the Prius got 51.7 MPG, not 38 MPG. Headwinds, air conditioning, and everything else was already accounted for in the 51.7 MPG because all the Prius does is measure fuel flow and miles driven and if the fuel flow was greater due to headwinds or air conditioners it would have been accounted for. If the computer was wrong on that day, it is always wrong, and if that computer was wrong when it matched the EPA and Consumer report estimates to within a percent or two, then all Prius computers are wrong, but they aren't, that's a fact. They exhibit a reasonable amount of variability with some being a tad high, some a tad low but that is irrelevant. If it is an inherent distrust of technology, then people shouldn't trust the odometer reading or the gas station pump reading either.
Why does everyone assume his calculation of 38 MPG was correct? What are the odds the Prius system would fail for this one test? Note also that the trip was 549 miles long but he called it at 422 miles. Why was that? Did he not know that a 2004 Prius would automatically reset the computer with a tank fill up? When he filled it up and started driving, how long did it take for him to realize his computer had reset? What else did he do wrong?
I too can smell diesel a mile away, especially biodiesel. Even my daughter now will tell me we are behind a biodiesel car before I smell it (her nose is younger and more sensitive). We have a lot of them here in Seattle (biodiesel cars and noses).
Nucbuddy,
Biodiesel. It's totally killer.
Maybe not the best analogy. Look at what it is doing here. Also, keep in mind that although biodiesel is certainly cleaner in most respects than regular diesel, there are compromises. Replacing a gasoline car with a biodiesel burning one is not cleaner at all and if you are using soybean oil instead of recycled, then you are also removing from the vegetable oil futures market 15 acres of soybean oil annually to feed your car.
Which might be thought strange, considering that...
Easily rectified. Just multiply your Prius computer mileage obtained by your simulation drive by those same factors, or inversely, divide the EPA ones by them. I didn't mention those factors for the sake of simplicity, but your point is valid.
Sunflower,
Nice link,
the average American does more to reduce global warming emissions by going vegetarian than by switching to a Prius.
One can make a similar argument for all kinds of things. One can forgo hot showers, a single family home, a car, washers and dryers, 70 degree room temperatures, vacation trips, and on and on. The people in our culture with the lightest environmental footprints are our homeless. They also are at the bottom of our status hierarchy. They are not envied (although, I have wondered on occasion if it might be better than bills and jobs). People will accept hardship if there is enough status to be gained. Like summating Everest and displaying the fact by hanging Tibetan prayer flags on your porch and a big framed picture of the event over your mantle. Find a way to make vegetarian diets popular. If you try to do that by making them high status you need a way to display it and make it envied by a large pool of people. The motivation to go vegetarian for most people isn't there. And if you can't find a way to motivate them, then find a way to make meat production less environmentally destructive --cow version of Beano, free range bison grazing on prairie grasses instead of feeding it to cars?
Spaceshaper,
This has to be one of the most commented threads in recent Grist history.
Not yet and I think you answered your own question better than I could have.
In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world
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JackSatan Posted 11:47 am
22 Jan 2007
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sunflower Posted 12:43 pm
22 Jan 2007
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Nucbuddy Posted 12:53 pm
22 Jan 2007
You need to re-think your math again. The average car in the US drives about 12,000 miles a year. Let's say the real-world MPG for the Prius is 48 MPG, and 22 MPG for the Scion. If you assume gas averages $4 a gallon over the next ten years (probably a low figure), you'll spend about $1000 a year on gas for the Prius, and about $1818 a year for gas for the Scion. If the Prius numbers are correct, you'd save about $65 a month, not the $16.30 you state. Over 10 years, that's a total of over $8000 in gas savings.
The Scion xA 4dr Hatch real-world averages 32 MPG.
http://www.truedelta.com/fuel_economy.php?stage=powertrai...=
The $12,000 extra for the Prius turns into $31,124.91 extra after ten years, assuming a 10% discount rate.
http://www.moneychimp.com/calculator/compound_interest_ca...
At $2/gallon, that would purchase over 15,000 gallons of gasoline, with which one might fuel a bonfire of the vanities.
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Biodiversivist Posted 1:11 pm
22 Jan 2007
http://gristmill.grist.org/story/2006/9/8/82015/17778...
In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world
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Biodiversivist Posted 1:53 pm
22 Jan 2007
In the end, it all comes down to biodiversity. Poison Darts--Protecting the biodiversity of our world
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amazingdrx Posted 12:00 am
24 Jan 2007
A plugin series hybrid (like the GM volt)substitutes an electric motor for the gas engine and transmission. The low speed torque and high RPM range of an electric motor makes a transmission unecessary.
By putting in enough battery capacity to match the average driving distance between charging opportunities, the plugin series hybrid can eliminate most gas consumption. The average distance is around 24 miles per day.
That range is affordable in dollars and weight with several different battery types now available, even without mass production anywhere near the level of mass production of internal combustion vehicles.
Yet another parallel hybrid is a waste of scarce time and capital. It is (past) time for some auto company that has not invested in parallel hybrids to go serial hybrid and skip the parallel hybrid path altogether. Or for the leaders in hybrids, like Toyota or Honda to dump the parallel hybrid and go serial.
Toyota seems commited to the parallel hybrid with sales of the Prius growing and new parallel models coming out. Honda is not doing as well with their parallel hybrid. And Honda is a world leader in generators, a necessary component of a serial hybrid.
I think it will be Honda that re-evolutionizes transportation energy with the first mass produced plugin serial hybrid.
The Prius brand could be preserved in plugin serial version, but it would be a whole new drivetrain. Come on Honda and Toyota bury the gas guzzler industry, these antiquated monopolies aren't helping anyone anymore.
With Tesla motors move to Detroit, trying to revive it, it will be an exciting contest.
From the Tesla blog http://www.teslamotors.com/blog1/?p=46
"while I was in Detroit, we opened our new Motor City engineering office in Rochester Hills, Mich., with a WhiteStar (our planned four door sports sedan) design review. We already have a dozen employees there, busily working on WhiteStar. We plan to continue hiring in Detroit, aiming for around 50 people there by the end of 2007."
Will Tesla wise up and go serial hybrid? We'll see.
http://amazngdrx.blogharbor.com/blog
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gmcjetpilot Posted 11:31 am
25 Aug 2008
First the EPA est for the prius are about 10% high and the EPA came out and admitted that. Also the EPA est for the VW TDI is woefully low, like 10 mpg lower. Most TDI drivers get near 50 mpg on highway, some way more, but most TDI drivers say they have to try hard to get less than 44 avg. The Prius in typical use does not get close to its inflated EPA est milage.
A new You Tube Video shows the TDI VW Jetta going from Auburn Washington state (just south of Seattle) to SanFran, about 733 miles. The drove the trip side by side with a Prius. Not only did the VW do it in one tank (prius did not) it did it like a real car. The VW has better feel and went over mountain the mountain pass with out breathing hard. The Prius not so much. All drivers loved the feel of the VW and the Prius was boring and had no rear window. Plus it got worse milage, ha ha ha ha ha. The new TDI VW may only use 5% Bio-diesel (fuel made from used veg oil) but that may go up. Even if that is all it ever takes the VW TDI is a real contender at 50/40 mpg.
Another milage round up with a popular car magazine (also a youtube video) with the VW, Prius, Mini Car and a small Ford, tests average, city driving and highway. The VW came in first milage but only because fuel price was factored in (Diesel cost about $0.05-$0.45 more). Based on pure energy use or MPG the VW was the winner.
The Prius is a nice car for around a small town with surface roads, stop and go, short distance lower speed where the elec part comes in more. That is a fact. Deal with it, the Prius is NOT A Panacea, it is a stop gap at best and an over priced status symbol for Greene's.
I test drove one, quiet, smooth, powerful, clean and better milage than the PREEISS. Who cares? I do.
After 5-7 yrs of Prius you have a $3000-$5000 battery bill with the prius, what land fill will that go in. The NEW common rail injected and regenerative NOX + particle filter after treatment in the new TDI VW plus low sulfur diesel fuel, makes is a winner. The Prius is s status simple for snobs to say LOOK AT ME AND HOW MUCH MONEY I SPENT TO SAVE THE PLANET.
What an author starts out with I DON'T CARE IF THE VW GETS BETTER MILAGE THAN HE SHOULD BE DICOUNTED. I on the other hand have an engineering back ground and can actually do MATH, that the liberal art major dreads.
With that said I embrace the Prius but the Diesel more. The defend the know weakness and hype it more than it deserves while putting down new diesel technology which is better in may ways is childish or emotional. As a person of science and numbers they don't lie. Sorry if you wasted you money on a Prius. May be a diesel elect hybrid will be better, or all elect when it time comes.
If we go elect car, we NEED NUKE POWER. Again it is emotional BULL that people oppose NUKE POWER. It has been very safe for the number of plants even including third world Chernobyl and 3-mile. No one died from 3-mile or any USA Nuke plant. Those where the early days. With standard design and more knowlege I would live next to a nuke plant. NUKE IS ZERO GREEN HOUSE AND WOULD CHAGE CARS ALL DAY AND NIGHT. Cheers
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