Study finds that increased vehicle travel and decreased occupancy have undercut the impact of improving fuel economy over last 40 years
06 March 2013
A new study by Dr. Michael Sivak, Director, Sustainable Worldwide Transportation, University of Michigan Transportation Research Institute (UMTRI), has found that from 1970-2010, an increase in vehicle distance travelled in the US, coupled with a decrease in the number of occupants in the vehicles, combined to undercut the impact of advances in vehicle fuel economy during that period.
From 1970 to 2010, vehicle distance travelled in the US increased by 155% (from 1.674 trillion km to 4.260 trillion km); however, because vehicle load (i.e., occupants carried) decreased by 27% (from 1.9 to 1.38 persons), the occupant distance travelled increased by 84% (from 3.182 to 5.867 trillion km). Sivak found that while the vehicle fuel economy of the entire light-duty fleet improved by 40% (from 13 mpg US to 21.6 mpg US, or from 18.1 l/100km to 10.9 l/100km), because of the decrease in vehicle load, the occupant fuel economy only improved by 17% (from 24.8 mpg US to 29.8 mpg US, or 9.5 to 7.9 l/100km).
As a consequence of the changes in vehicle fuel economy, vehicle distance travelled, and vehicle load, the total amount of fuel used increased by 53% (from 303 to 463 billion liters).—Sivak 2013
|According to the 2011 American Community Survey by the US Census Bureau, 79.9% of workers not working at home drove to work alone.|
The study includes a brief discussion on the effects of potential future changes in vehicle fuel economy, vehicle distance travelled, and vehicle load on the amount of fuel used for personal transportation.
Sivak notes that:
Nominal reductions in fuel consumption due to improved fuel economy need to be adjusted downward due to the rebound effect. (EPA recommends a 10% decrement.) In other words, a 20% increase in fuel economy would result in a net 18% reduction in fuel consumption.
Because changes in fuel economy take a long time to percolate through the entire fleet, an 18% reduction in fuel used by vehicles purchased in a given year (due to a 20% improvement in their fuel economy) would result in only about a 1% reduction of the fuel used by the entire fleet.
(This has led some researchers to argue that the policy emphasis should be on reducing vehicle distance traveled through an increased fuel tax—with fleet-wide effect.)
Because the amount of fuel consumed is directly proportional to vehicle distance traveled (holding everything else constant), a 20% decrease in vehicle distance traveled would translate into a 20% reduction in fuel used.
Increasing occupancy (e.g., through ride sharing) reduces vehicle distance traveled, and also slightly worsens fuel economy due to the extra weight. In a scenario of increasing vehicle load by 20% from the current 1.38 to 1.66 occupants, vehicle distance travelled would be reduced by about 15%, while vehicle fuel economy would worsen by about 1%. Combining these two effects yields a reduction of about 14% in the amount of fuel used.
The study was supported by Sustainable Worldwide Transportation. The current members include Autoliv Electronics, Bridgestone Americas Tire Operations, China FAW Group, General Motors, Honda R&D Americas, Meritor WABCO, Michelin Americas Research, Nissan Technical Center North America, Renault, Saudi Aramco, Toyota Motor Engineering and Manufacturing North America, and Volkswagen Group of North America.
Michael Sivak (2013) Effects Of Vehicle Fuel Economy, Distance Travelled, And Vehicle Load On The Amount Of Fuel Used For Personal Transportation In The US: 1970-2010 (UMTRI-2013-10)
"As a consequence of the changes in vehicle fuel economy, vehicle distance travelled, and vehicle load, the total amount of fuel used increased by 53% (from 303 to 463 billion liters)."
But keep in mind that the US population increased by a similar percentage (52%)during the 1970-2010 period (see US census data). If average driving distances have indeed increased and user occupancy decreased, those factors have actually probably been totally made up for by increases in efficiency. What remains is more fuel being used to move around many more people.
Posted by: RD | 06 March 2013 at 04:38 AM
I think this confirms that no matter what the price of fuel or the efficiency of the vehicles the consumer mentality of the US populace will always drive them to consume to the highest level possible without consideration of the consequences. They will whine too. However, they could simply live within their means and save money rather than spend it. However, their lives are empty shells of superficiality and they must fill the void with useless junk that no one needs. Our leaders are lucky too, that they have such a shallow, ignorant and easily manipulated mass of people out there. Otherwise they might actually be capable of improving the country and possibly they would be held accountable for their ineptitude rather than simply blaming the problems on the rank and file federal workers.
Posted by: Brotherkenny4 | 06 March 2013 at 07:24 AM
Yes, and 2012 will soon be officially declared (with 2011) the year with all time highest human made emissions.
Tokyo's goals may not be met for years/decades to come unless:
1. transition to electrified vehicles is accelerated.
2. dirty coal fired power plants are modified or turn down.
3. transition to clean e-power sources is accelerated.
4. Garbage dumps are eliminated or gas emission fully captured.
5. shale gas and shale/tar sands operations are cleaned up.
6. 101 other actions
It is fair to conclude that it will not happen this year or during this decade.
Posted by: HarveyD | 06 March 2013 at 08:12 AM
Interetingly, given the numbers presented here and the census data for 1970 and 2010, in forty years the per capita fuel usage rate in the US stayed at about 1,500 Liters. Wow-talk about stasis!
Posted by: RD | 06 March 2013 at 08:36 AM
Adjusted for inflation, we are paying about the same for gasoline. People complain about $4 gasoline in the U.S., a gasoline tax would bring about a call to "throw the bums out".
The U.S. burns 300 million gallons of gasoline per DAY! I hope that number sinks in so people can really look at their consumption patterns and help reduce the amount of imported oil soon.
Posted by: SJC | 06 March 2013 at 09:21 AM
40 years ago most families only had one car and it was likely that only one parent had a job. Or at least that's how I remember my family.
Posted by: ai_vin | 06 March 2013 at 09:32 AM
After all that Reaganomic trickle down, 5% of the people ended up with 95% of the wealth increase.
Posted by: SJC | 06 March 2013 at 10:14 AM
So, essentially, we are each doing 50% more work, while using the same amount of resources. That's not all bad.
What I want to know is: what is the overall trend?
The article tells us that we are at the same level (per-capita) as in 1970, but what about 1980, 1990, 2000?
Have we passed "peak consumption", or did consumption bottom-out 20 years ago and it is now increasing?
Without more data, the fact that 1970 matches 2010 tells us nothing.
Posted by: Bernard | 06 March 2013 at 11:21 AM
Imagine all the one car families not commuting great distances with twice the mileage compared to 1970, we might not be importing as much oil.
Posted by: SJC | 06 March 2013 at 03:04 PM
"After all that Reaganomic trickle down.. "
I wonder if SJC was even born when Reagan was POTUS or is just a victim of a bankrupt California school system.
People do not drive great distances to work because they enjoy freeway driving. They want to their kids to go to schools controlled by teachers dedicated to educating children not a bunch of draft dodging hippies who are as stoned as the gangs that have took over the schools.
Posted by: Kit P | 06 March 2013 at 03:54 PM
Those kind of comments don't help the discussion.
Posted by: SJC | 06 March 2013 at 07:00 PM
I like the advanced concepts and higher math presented.
"Because the amount of fuel consumed is directly proportional to vehicle distance traveled (holding everything else constant), a 20% decrease in vehicle distance traveled would translate into a 20% reduction in fuel used."
Oh, and the discussion is beyond help.
Posted by: ToppaTom | 07 March 2013 at 01:33 AM
In 1982 we had high inflation, then Reagan signed a bill taking away interest deductions for credit cards and car loans, arguably the largest tax increase on the middle class ever.
Now you have BOTH adults in the household having to work and needing two cars to commute to and from work. Even though fuel mileage was up, so were the number of cars and miles driven.
I was pointing out some of the driving forces that led to this, it was part of Reaganomics where the rich get richer and they did. Then we get comments about hippies and school systems.
Posted by: SJC | 07 March 2013 at 06:56 AM
What's wrong with the American school system? The lack of good science.
A few decades ago the fundies realised they had no hope of taking over in the national political stage so they focused on the small local systems - like the school boards. These are people who hate science. As it is now roughly half of the people in the United States reject one or more fundamental tenets of science (most commonly evolution), while a larger percent, perhaps more than 80 percent depending on how we measure, would fail a basic science test. A strong majority of those American citizens who would claim to have strong feelings about one or more science policy issues such as climate change, stem cell research, or nuclear power either know very little about the relevant science or are so badly informed regarding the science that their knowledge is not merely insufficient, but is actually opposite what is generally accepted by experts in the area. But then "somebody has to stand up to the experts" http://www.youtube.com/watch?v=pzrUt9CHtpY
Posted by: ai_vin | 07 March 2013 at 08:25 AM
Posted by: ai_vin | 07 March 2013 at 08:38 AM
Is it the 80/20 rule taking over in education or is it the 95/5 rule going to the 97/3 soon?
Posted by: HarveyD | 07 March 2013 at 11:59 AM
“In 1982 we had high inflation ...”
Could SJC be repeating the agenda of his hippie social studies teacher or is he a flat out liar?
Inflation increased from 5% to 15% when Jimmy Carter was POTUS. When Reagan took the helm, inflation was driven back below 5% in four years.
“taking away interest deductions for credit cards and car loans ”
It was only a tax deduction for those who were irresponsible with their credit cards and bought big expensive cars. I not sure why anyone would think that the federal government should subsidize irresponsible credit card spending and big car payments.
“Now you have BOTH adults in the household having to work and needing two cars to commute to and from work. ”
Again that is not true. It is a choice. When we moved from California, we decided to buy a house based on one income and no new cars. When you are busy reading to your kids, the reward is worth more than all the wealth in the world. It is amazing that folks who are busy spending their money on recreational drugs fail to make the connection with not being able to afford a decent place to live. Blame it on POTUS, it does not matter which one.
Posted by: Kit P | 07 March 2013 at 04:55 PM
Inflation increased from 5% to 15% when Jimmy Carter was POTUS. When Reagan took the helm, inflation was driven back below 5% in four years.
Posted by: ai_vin | 07 March 2013 at 09:26 PM
I hope I was smart enough not to lecture my parents about the depression, WWII, and the Korea War because of something that a school teacher told me. Inflation is a terrible thing. Millions of Americans could not afford to heat their house because the cost of heating oil went from 25c/gal to $1.15. At the time I was in the navy and Carter thought that you could control the budget by not adjusting the pay of the military for inflation. I was the king of the car pool since I had a IH TravelAll instead of Pinto.
“rich get richer ”
One gets tired of this socialist crap. The solution is not for everyone to get poorer. If you want to me unhappy because others have more, that is a choice you make and you will still be unhappy when the next clown in in the White House.
Poverty is a state of mind. It costs nothing to pick the litter up in your yard and plant flowers. There is pride in ownership of that old single wide. Who is richer, the person stuck on the freeway in his BMW or the person who needs a riding lawn mower for the acre old single wide?
Posted by: Kit P | 08 March 2013 at 05:36 AM
BTW I believe we can pin the high inflation rates of the Carter years to; http://en.wikipedia.org/wiki/1979_energy_crisis
“rich get richer ”
One gets tired of this socialist crap. The solution is not for everyone to get poorer.
Nobody ever said it was. That's just a strawman attack.
Posted by: ai_vin | 08 March 2013 at 08:24 AM
There is much disinformation being spread here.
Fuel consumption per capita is the ONLY measure that merits discussion. It hasn't changed much, even as travel per capita has increased markedly. This means that vehicle efficiency has increased even as pollution has gone way down. It also means that the average citizen's mobility and freedom has increased as well.
Imported oil statistics are indeed awesomely positive At the turn of the Century the USA was importing 12 million barrels of Oil per day. Now it is down to just about 6 milion barrels per day, with most of it now coming from the Western Hemisphere, freeing the US and Canada from dependence on unstable Mid East regimes.
Oil reserves and petroleum resources are much better today than at any time since the late 1960s, and more and more Oil is being found. The Russian belief that Oil is mostly abiotic in origin, and enormous quantities are being created geologically, is gaining acceptance and removes much of the concern for resource exhaustion for Centuries and Millenia.
We have now proven that western technological civilization can adapt and endure the myths propagated that forecast its doom and non-sustainability. It will not run out of any resource nor drown in its created pollution.
The places with the worst pollution are, as ever, the stupid Socialist regimes where a tight core of self- appointed oligarchs lord it over the rest of the population.
Posted by: D | 11 March 2013 at 05:46 PM
The Russian belief that Oil is mostly abiotic in origin, and enormous quantities are being created geologically, is gaining acceptance and removes much of the concern for resource exhaustion for Centuries and Millenia.
"The abiotic oil hypothesis is an attempt to explain the source and formation of petroleum. As the name suggests, the hypothesis proposes that oil originates from non-biological origins.
The hypothesis is mostly Soviet, mostly archaic, and mostly debunked. In the Anglophone world, abiotic oil proponents tend to cite the work of the late astrophysicist Thomas Gold."
"No oil company has ever successfully found a well using the theory and it is generally considered pseudoscience on the order of global warming denialism. It originated in the Soviet Union, its major scientific supporters worked in Russia, and it has never gained a following anywhere outside the Soviet Union. Having largely passed with the USSR, it occasionally makes a comeback among less intellectual conservative elements, where it is used as an excuse to continue ignoring the energy crisis of the future. Russian creationists also favour it.
The Swedes, in fact, drilled in Siljan at Gold's behest and only came up with 80 barrels of oily sludge over a six year period, which easily may have been residue from oil lubricant used in the drilling machinery. Abiotic oil proponents, however, continue to cherry-pick minor increases in production at certain oil wells and declare it as "proof" of abiotic oil."
Posted by: ai_vin | 12 March 2013 at 03:19 PM