"Between 1980 and 2006," the MIT report begins, "the average gas mileage of vehicles sold in the United States increased by slightly more than 15 percent -- a relatively modest improvement."
The study by MIT economist Christopher Knittel seems silly to most of us; we KNOW the answer here. Without looking at the spoiler photo above, those of you reading Inside Line, who've spend more man-hours researching car information for fun than Knittel ever will for his profession, know why our fuel economy numbers haven't risen as high as they could.
Weight. Power. (Damn, I miss that G8.)
Knittel explains that during that time the average car has seen an increase in curb weight of 26 percent and has 107 percent more horsepower. He goes on to explain that if we had modern engines in cars that were the same size, fuel economy would have jumped to "roughly 37 mpg, well above the current average of around 27 mpg."
"Most of that technological progress has gone into [compensating for] weight and horsepower." said Knittel.
Again, I think anyone reading this knew that weight (from safety features, buyer preferences, etc) and power were behind this, but sometimes it takes a critical eye from a respected researcher to get the public's attention.
Knittel, however, doesn't trust the public to see the problem and do anything about it. "When it comes to climate change, leaving the market alone isn't going to lead to the efficient outcome. The right starting point is a gas tax."
According to the report, the total transportation sector is responsible for 30 percent of greenhouse gas emissions.
(MIT)
throwback says:
09:53 AM, 01/ 6/12
I thought only smart people worked at MIT, his answer to cars gaining weight and getting more powerful engines is a gas tax? It's sad that reducing weight and thus reducing engine power isn't an option to him. Perhaps he should spend some time at the engineering school. He must be from the school of, "the answer to every problem is more taxes."
exnevadan says:
10:05 AM, 01/ 6/12
well, MIT is located in Taxachusetts
sniperruff says:
10:10 AM, 01/ 6/12
@throwback:
"reducing weight and thus reducing engine power isn't an option to him"
- It's not an option for US consumers, not him.
"Perhaps he should spend some time at the engineering school."
- He is an economist.
"the answer to every problem is more taxes"
- Read this: http://en.wikipedia.org/wiki/Fuel_taxes_in_the_United_States#Public_policy
creeper says:
10:14 AM, 01/ 6/12
he's an ECONOMIST, not an engineer. therefore the only logical solution for him to come to is to affect a change in the public's desire for bigger, heavier and more powerful vehicles is by making them more costly to obtain and operate.
zimtheinvader says:
10:17 AM, 01/ 6/12
so a gas tax is going to get people to go backwards into little, loud inside, deathtraps?
greenpony says:
10:20 AM, 01/ 6/12
Interesting. So, after reading this and a similar report posted on the EPA website (comparing years 1990 through 2009) you can conclude:
- Fuel economy improved DESPITE substantial increases in both weight and power
- Of the "transportation" sector, "nearly 65 percent" of these emissions are from "personal vehicle use" (that's actually higher than I thought)
- Emissions increased by 16% since 1990 despite an increase in vehicle miles traveled of 39%
- Transportation sector emissions actually decreased by 9.2% between 2007 and 2009, while overall emissions decreased by 10.0% in the same period
- Overall emissions in 2009 are actually BELOW 1996 levels
That looks like significant progress, especially in the last three years of data where the bar graph plummets. I would like to see 2010 and 2011 data to see if the trend continues. What about the study that contains data only through 2006? Take from it what you will, but I give little credence to a study whose most recent data is six years old, especially since it omits the dramatic improvement shown between 2007 to 2009 in the EPA report.
chewieyak says:
10:33 AM, 01/ 6/12
Actually, his analysis makes sense from an economic point of view. Think of it this way: When gas prices go up, people want more fuel efficient vehicles. When gas prices were at or near $4 a gallon, lots of people moved away from their SUVs to get hybrids or more fuel efficient vehicles. As such, the Big 3 scrambled to get more efficient vehicles on the road to meet demand.
I don't like taxes anymore than the next person but his suggestion is valid.
e30bmw says:
10:51 AM, 01/ 6/12
Throwback, do you not understand that your asnwer is the end result of a gas tax. What he is proposing is to tax people in order to force people to give up the horsepower and downsize vehicles. Maybe you should think before you insult someone.
autoboy1 says:
10:57 AM, 01/ 6/12
Adding lightness costs money. Lots of it. Returning to 80's weights would also compromise safety. Once again the environmental idiots focus on the boogeyman global warming rather than the real world benefits the added weight did to vehicle safety. They seem to want to kill us all in their quest to save us from ourselves.
lostboyz says:
11:28 AM, 01/ 6/12
What's more important safe cars or efficient cars? NHTSA says safe, EPA says efficient, so we have to somehow try and do both.
Beyond that, if you want to increase true fuel economy as in, what the cars actually achieve I say we need to scrap our current driver's education. I can't say that even 10% of drivers have a clue of what they are doing out there.
duck87 says:
11:49 AM, 01/ 6/12
He's an economist/beancounter, not an engineer. I wouldn't have expected an engineering oriented solution out of him.
kain77 says:
12:24 PM, 01/ 6/12
In other news: snozberries taste like snozberries
julianb says:
12:42 PM, 01/ 6/12
First of all, increases in horsepower are due increased fuel mileage. Someone in the science or engineering department at MIT should have told this guy that reducing engine friction, optimizing combustion, engine downsizing accompanied by turbocharging and other fuel efficient improvements ALL increase Fuel Mileage and Horsepower simultaneously! As powertrains become more efficient both will always increase together. Energy Efficiency=Eout/Ein. Energy efficiency is basically Fuel Mileage in this case and HP is Eout. That equation shows that both increase together!
Also increased weight is due to increased safety regulations. Obviously those cars in the 80's lack a lot of the safety equipment that are on today's cars.
I know this Economist is Obviously NOT a Scientist but politicians, economist, journalist, business men and women are losing the leverage to comment on or make technical decisions due to their lack of scientific education. This is a prime example of that.
stoppre75 says:
12:56 PM, 01/ 6/12
@Throwback:
No, his answer to transportation being responsible for 30% of greenhouse gas emissions is a tax. This story was written with a slant so great, filled with "duh, no kidding's" as a further way to discredit him, I'm surprised the words stayed on the screen.
If you actually read the M.I.T new or the paper (http://pubs.its.ucdavis.edu/download_pdf.php?id=1305) you'll see he's actually an economist who values the future of Earth.
"And considering that the transportation sector produces more than 30 percent of U.S. greenhouse gas emissions, turning that [automobile] innovation into increased overall mileage would produce notable environmental benefits. For his part, Knittel thinks it is understandable that consumers would opt for large, powerful vehicles, and that the most logical way to reduce emissions is through an increased gas tax that leads consumers to value fuel efficiency more highly."
I don't agree with his position. Simply because transportation accounts for 30%...but semi-trucks are the majority of that. Passenger cars are 12% of the total problem...Why are we focusing so much energy on 12% of the problem??? Force semi's to run on CNG, force coal fired power plants to scrub the exhaust - don't force the smallest minority to shoulder the majority of the responsibility. To combat energy needs while acting responsibly requires us to stay local and use the most suitable alternatives for our specific region. (Solar in the SW, Wind in the northern Plains, tidal in NYC) coupled with a cleaner form of whatever currently powers our electric needs. From there you can actually make an impactful difference on total emissions.
Reducing passenger car emissions by 50% would mean a 6% reduction in overall CO2 emissions in the US. Reducing the emissions of electricity generation and industrial use by just 9.15% would net the same reduction. That's how you fix the problem, not by taxing the relatively clean unleaded gasoline.
http://epa.gov/climatechange/emissions/downloads11/US-GHG-Inventory-2011-Executive-Summary.pdf
mcesarey says:
12:08 AM, 01/ 7/12
Of course, this economist's opinion won't go over well in a forum full of gear-heads, but he is absolutely correct.
I don't want gas to be more expensive, but it absolutely changes the buying behavior of the public. I'm in England at the moment, where you can buy cars that get 50-60 mpg all day long, because gas is about 2.5 times as expensive as in the states.
There is a ton of room for greater efficiency in the American vehicle market, but it's driven by buying behavior. For example, we can't even buy a diesel F-150, and Americans bought over a half-million F-150s last year. Even performance cars here have a diesel option and we can't get it in a truck? To me, that is beyond stupid.
transpower says:
06:13 AM, 01/ 7/12
Here are some ideas for better fuel efficiency:
1. Use higher compression ratios in Diesel and Otto-cycle engines.
2. Use real Atkinson-cycle (complete expansion) engines.
3. Develop the Satz rotary positive-displacement hot gas regenerative engine--this solves the gas turbine temperature problem.
4. Use more gears or make more use of the CVT.
5. Use lighter weight body materials.
6. Develop more efficient tires.
7. Lower the aerodynamic drag coefficients.
8. Convert exhaust heat into electricity to power accessories on-board.
9. Develop more efficient battery technology for hybrids. Keep the batteries at their optimal temperature.
acbayard says:
06:36 PM, 01/ 7/12
It isn't exactly the "public's fault."
There's an inherent prisoner's dilemma in the race for better crash standards. If all manufactures got together and agreed to weight limits, standard impact height/zones - we'll be all safer.
But there's no such gentlemen's agreement - but plenty of crash testing.
chochmastergen says:
08:30 AM, 01/10/12
Fuel economy could be improved a lot if people were taken out of the driver seat for daily commutes. If cars had some sort of networked auto pilot to and from work, using the same cars and the same roads in the same or less time, everyone could get to work with much better mileage.