Illusion of MPG

We have a winner for the stupidest thing I've read all day. Congratulations.

Statistics allow us to see through the noise and see what is really happening. Anyway, this isn't stats, this is grade 4 math.

Here is the original article for those that are interested.

I've always felt that giving a tax break to Prius owners is like lecturing to the converted. A lot of people who buy Prius's would have bought a relatively fuel efficient car anyway so is it really a good use of tax payer money to subsidize such a purchase? This article suggests that tax credits should actually go to the SUV hybrid owners. I never considered that before but after reading the article it does make sense. Interesting read.

 

Has your wife talked to my wife? The first thing I hear when my wife arrives home with bags in her hands is how much $$$ she saved. Now that I am driving a Prius versus a Highlander SUV I found her logic to be completely clear, however I still get the urge to hide the credit cards.

 

I thougt about getting a beater for a short time (btw, the ford dealer will only give you $1,500 for a 5 year old expedition, so there ARE great deals out there). Say for example I needed to move 50 sheets of drywall from Home Depot to our home, just 4 miles away. But Home Depot will rent me their mongo truck (for just $19.00) at 75 minute increments. Heck, I might be a little slow sometimes, but the Home Depot truck will do the trick just fine ... for a lot less than the cost of insurance and registration.

Subsidizing only makes sense if it's a giant tracter trailer rig. They HAVE to be that size. But mom & the kids will fit fine in any ol car. That's why you don't see land barges all over the landscape in europe & asia. I'm not talking about their better mass transit programs, rather the folks who drive. They do it. We can do it.

 

I think part of what people are saying is that a vast majority of people buying SUVs don't need them. My wife very much wants a HiHy and her reasoning is that when family visits and we want to go out to dinner, or if we want to buy something at Ikea, it would be really nice to have. So maybe 3-4 times a year.

Instead we could save money and get a second prius and save even more gas. Sure saving 333 gallons of gas is impressive by going from 10-15 mpg... But saving 778 gallons by going from 10-45 mpg is even better. Thats an additional 445 gallons of gas a year.

I think thats what TonyP was trying to get across with his light hearted comment about statistics. Stats are just raw data and can usually be manipulated to show what the presenter wants them to show. That article used them to show that hybrid suvs save more gas over standard suvs than hybrid cars do over other fuel efficient standard cars. You can use the same data to show that the hybrid suvs aren't really fuel efficient and you can save a lot more gas by going with a prius/civic hybrid.

 

Sorry, that's incorrect, raw data are not statistics; raw data are just that: data. Statistics is the field of analysis and interpretation of data - it's quite different. What the article is saying is that the common statistic - MPG is frequently interpreted incorrectly due to the curvilinear relationship with gas usage and distance travelled - and suggest that it be switched to volume per distance (L per which does not exhibit this relationship. If this is done, people (and in particular policy makers) can make decisions based on the correct interpretation of a statistic to reduce overall fuel consumption - on a country wide level.

I threw in that for people who insist on buying SUVs - they are out there - that encouraging them to purchase hybrids (something they normally wouldn't do) should be encouraged by giving them HOV stickers. Prius-pron (for lack of a better term) people will buy one anyway (hence the waiting lists) so there is no reason to give them tax payer subsidized incentives.

 

I think we are maybe a little guilty of that, but it's more from the number we see being driven to and from work with just one person in them.

An interesting calculation (I got the idea from a pro-carpooling site years ago) is to figure out mpg based on the mpg of the vehicle times the number of passengers. A 13 mpg SUV (like my old Blazer) is getting the equivalent of 26 mpg if I carpool with one person(and thus split the gas and wear and tear two ways). If I vanpool in a 15 mpg minivan carrying 4 people, we are getting the equivalent of 60 mpg.

Of course, my carpool continues, so now I get 108 mpg which is really nice. And just think what a carpool of two does for your carbon footprint!

Even that single driver in an SUV may normally be a member of a carpool, but have a medical appt, or their carpooler may be ill or on vacation.

 

Very good point.
For me, it isn't so much about bashing the SUVs. Just as said above, it is a matter of the SUV drivers that don't need them.
And the stupidity of those driving the biggest of SUVs, that don't need them and then complain about gas prices. Those are the ones that really get my goat.

 

You must think PC members are a fairly stupid lot. I think most of us got the thrust of your original post - it's not particularly hard to understand, even obvious to a non-statistician if they stop and think about it for a bit.

Some members of this board have a sense of humor. Tony is one of them. I believe the quotation for which he was searching is this one: "There are three kinds of lies: lies, damned lies, and statistics." This saying was popularized by Mark Twain, and generally attributed to Benjamin Disraeli.

Obviously, formal statistics are mathematically sound. The problem lies with what is passed off as statistics by the media. Statistical figures are printed and quoted without any reference to the data and methods used to generate the results, and as a result are about as useful as warts on a pickle. My father was a master of that sort of thing. He would stick his head into the room on Saturday morning while we were watching cartoons and ask us which one of two designs we liked. Three of us would pick design A and one design B. His report would then state: "Of the people surveyed, three out of four preferred design A over all other designs." It was entirely true, and mostly useless. He never said there were only two designs, four people, and that we were all kids.

Lighten up and enjoy the humor a bit. Besides, it's a well known fact that 96% of all statistics are made up on the spot.

Tom

 

Is that a corollary of the saying -- there are 3 types of liars: liars, damned liars, and politicians? But, let's not stop there. We need to also include lawyers, political analysts, journalists, reporters, and Art Spinella (of CNW Research), all of whom are adept at manipulating statistics for their own agenda.

 

Exactly! Here in SoCal I continually see the majority of SUVs and Pickups hauling 1 person. I really like Narf's reference to the term "false dichotomy", which is especially relevant to this whole discussion. It's all about options -- evaluating all the options. Options like caravaning with multiple small cars when the need arises, or renting a van or pickup by the hour or day, or installing a roof rack or trailer hitch. Granted, there will always be a percentage of people whose only legitimate option is a large or powerful vehicle for whatever reason. But for the vast majority, there are usually many other options that get brushed aside in favor of convenience.

There's a guy I work with who drives a huge extended cab diesel pickup that gets about 15mpg downhill with a tailwind. After many conversations I was able to gather that he actually uses it about once a month to haul something. 95% of its utilization is to drive solo, 60 miles round trip each day. I did the math for him, using actual local fuel prices for diesel and RUL, 15mpg vs 50mpg for a Prius, and his fuel savings would be $253/month. I mentioned to him, and he agreed, that's plenty enough money to occasionally rent a big vehicle. The next words out of his mouth were, "well it's too late to trade it in now, I'll lose thousands of dollars on the deal. Big vehicles just aren't selling these days."

 

My dad used the saying "Figures don't lie, but liars sure can figure.".

 

Yup! That is what I just did. I went from a V8 Tundra to a Prius - by the way, every tank I have consumed thus far has been a 50mpg average, not 45.

 

You bring up a very interesting point. I did some figuring based on my commute-only mileage. If I drove strictly for commuting and did no errands, I would be using just under 5.3 gallon/month. I arrived at those figures by taking my gallons/day(90+mpg X 5 X 4.25). 90mpg is .244 gallons for my 22 mile round trip and I have been over 90 for the last 37 days with close to a dozen days over 100mpg sprinkled in.

 

The opposite just dawned on me this weekend. I've been monitoring the Avalon with the SGII. We've been averaging ~18 mpg per tank, but ~25mpg on the weekends. My wife commutes 4 days a week ~30mi/day or 120mi/week. It just dawned on me that if I'm getting ~25 on a tank, fillup ~15gal/week for ~270mi/week, then my wifes commute is using over twice as much gas to go less than half of miles.
(270m/t)/(15g/t)=18/m/g/tank
(150m/wknd)/(25m/g/wknd)=6g/wknd
(15/g/t)-(6g/t)=9g/cmut
(120m/cmut)/(9g/cmut)=13.3m/g commuting
Terrain not that different. Start/Stop traffic major difference. No, flex times won't work. She's an RN at a hospital outpatient clinic. Work hours are determined by Clinic's and Doctor's hours. She'll drive the Prius. I'll get the Avalon. Retire the Ford Club Wagon. I have my own business and work from home, so very low mileage for me, should bring average mpg closer to the ~25mpg weekend average. We're anxious to see what kind of mileage the Prius will give us under these Metro Atlanta driving conditions. We know it's got to be better than the Avalon.
We are actually back to ~18mpg on the Avalon. We had it up to ~21 after switching to Mobil1, 42/40psi, and smarter driving habits. We got the ~21 for 5 tankfuls. Then along came E10, and now we're back to ~18mpg. Oh Well! That's better than dropping to ~15mpg.

 

Interesting. 34 posts and no mention that the USA should adopt the metric system (L/100km in this case) and forget about this confusion (which, IMHO, was the point of this study/video clip).

 

USAmericans now are too stupid to learn the metric system. Maybe in another generation, after most of those suffering from the effects of childhood exposure to leaded gasoline and paint have died.

 

People can say that they bought their SUV for space all they want but the truth is that I can fit just as many people in my Prius as I could in the Explorer we had. Explorer got 15 MPG and I usually average about 58 MPG in the Prius. An SUV is just such a waste unless you are seriously using it to haul. The two or three times a year that I actually need a large vehicle (bought a new fridge, TV, etc...) its easier to just borrow a truck from a friend or relative or pay the $30 for the delivery.

 

Forget that. After we go the ones who have been protected from everything will take over. You know the generation I mean. They even wear helmets during sex in case they fall off. Changing to the metric system will be way to traumatic for them to even consider.

 

Older SUVs bought in "better times" and being nursed through these
lean times out of necessity is one thing. A brand new SUV is another.

More is involved in a vehicle purchase than simple utility and pure
economics. Ego, perceptions of self worth, comparison's with past
generations (or the "Joneses," other ethnic groups, family members,
the list goes on and on), plain old one-up-manship, a sense of
entitlement to the "good life" what ever that is, and plain old outright
denial.

Clearly this is not hard science, it's psychology, and it's mushy as hell.
A corollary would be that this kind of rationalization is highly
susceptible to manipulation.

I reject the car maker's contention that they didn't create the SUV
demand, that they were just responding to consumer demand. SUVs
are high profit units, their investors demanded high short term
returns, they took the easy and profitable way out; they created the
market to which they then responded... and laughed all the way to the
bank.

Can the majority of car buyers' perceptions of the desirability of
smaller, more fuel efficient vehicles also be manipulated? Yes, but by
whom? It is a long, costly process.