# Presentation: 045964

## The Road Ahead for Light Duty Vehicle Fuel Demand

**The Road Ahead for Light Duty Vehicle Fuel Demand**

**Joanne Shore**
**Energy Information Administration**
**July 7, 2005**

**Notes:**
This presentation explores light duty vehicle fuel demand to better understand both what influenced its growth historically, and what could alter its growth over the next 15 years.

## Refining Capacity Surplus Shrank As Demand Grew, Creating Future Challenges

**Gross Inputs**

**Operable Capacity**

**Source: EIA**

**Notes:**
With refining capacity running near capacity during the summer months, concerns over rapid demand growth and available capacity to meet that demand have increased.  

The U.S. experienced excess capacity for many years, until demand caught up in about the mid 1990’s.  

While both capacity and demand have grown since then, product imports have helped to meet our growing demand needs.  

With world demand as well as U.S. demand growing faster than capacity, world refining utilization has also increased.  Although the world is not out of refining capacity, more will be needed.

In the U.S., refiners are planning new capacity in the face of regulatory, technological, and market uncertainties.  The remaining slides will focus on uncertainties associated with demand.

## Demand – A Crucial Factor Affecting Capacity Decisions

**Transportation is major growth sector**
**What could affect future growth?**

**Source: EIA**

**Notes:**
Clearly future demand growth is an important variable in determining future supply needs.

U.S. demand more than tripled in the 50 years from 1950 to 2000, driven mainly by growth in transportation fuel demand, which went from just over half of petroleum demand in 1950 to over 2/3 of demand by the year 2000.

But will such growth continue in the future, and what might change that pattern?

## Future: U.S. Transportation Demand Growth Drives EIA’s Reference Case

**Source: EIA, Annual Energy Outlook 2005**

**Notes:**
Most “reference case” or “business as usual” forecasts today show petroleum demand in the United States continuing to grow over the next 25 years or so, driven by transportation fuels.

EIA’s Reference Case shows petroleum demand for transportation fuels reaching a level in 15 years that is about 30% greater than petroleum transportation demand today.  An additional 4.5 million barrels per day of transportation fuel will needed over what is supplied today, which indicates a need for more capacity – either in the United States or abroad to supply that increase.

Factors can change this outlook.  It would seem that a significant slowing in demand growth or a significant shift in the mix between diesel and gasoline could have tremendous impacts on the shape of the refining industry in the future.  

The potential size and timing of such changes are explored in the remainder of this presentation.

## Presentation Overview

**U.S. history and factors affecting light duty vehicle fuel demand**
**European experience: Can diesel-fueled vehicles play a similar role in the U.S.?**
**U.S. future: Reference Case & variations**
**Modest changes in vehicle technology can slow demand growth significantly – but not quickly**
**Hybrids and diesel vehicles can add to this impact**
**But stopping demand growth is unlikely**
**Policy changes are needed to slow growth**

**Notes:**
Light duty vehicle demand comprises about 60% of total transportation demand, and is where much of the uncertainty in future growth lies.  

I will begin by introducing some of the major factors affecting light duty vehicle fuel use in the United States historically.

Then I will talk briefly about Europe, which chose a different path with its light duty vehicle use, in order to see if the European experience might provide any insights into our future.

The last part of the presentation will summarize some illustrative future scenarios to show how demand might vary in order to help assess the likelihood and timing for variations in demand.

## Factors Affecting Light Duty Vehicle (LDV) Petroleum Fuel Consumption

**Efficiency (MPG)**

**Miles Traveled**

**Driving population**
**Miles driven per driver**
**Personal Income**
**Cost to drive**
**Other (Age, sex, etc.)**

**Technology**
**Power Train **
**Hybrids**
**Diesel **
**Vehicle Mix (Cars v trucks)**

**Alternative Fuels**

**Hydrogen, All Electric, All Ethanol, Natural Gas**

**Notes:**
This talk will cover several factors that could affect light duty vehicle petroleum demand: the miles that are traveled and the efficiency with which the miles are traveled.  While alternative fuels such as hydrogen and natural gas would affect the need for petroleum refining capacity, such fuels are not likely to have a large impact in next 20-25 years, and thus will not be addressed.

Miles traveled is a function both of general population growth, which affects how many drivers are available, and the behavior of those drivers.  Personal income is probably the largest factor influencing driver behavior.

Efficiency of automobiles comes both from engine and car design, including the power trains being used.  Diesel engines are more efficient than gasoline, as are hybrid cars.  Also, the mix of light duty trucks – i.e., SUVs – and cars affects the fleet efficiency as average vehicle weight is much higher for trucks.  

## VMT: More Vehicles Per Driver and More Miles Per Driver

**Note: VMT – Vehicle miles traveled.**
**Source: Summary of  Travel  Trends, 2001 National Household  Travel Survey, ORNL**

**Vehicles per Driver**

**Notes:**
Miles traveled is affected both by the number of drivers, which rises with population growth, and driver behavior – i.e.,  how many miles an individual driver travels.  

The National Household Travel Survey indicated that in recent years, that mileage increase is the result of longer commuting trips, although as recently as 1990, social  and recreational  purposes had longer trips. In addition to longer trips for commuting, the number of workers per household has increased, which is attributed  in part to the return of retirees into the workplace.

Another factor that changed is the increase in how many vehicles are available to drivers.  

The major factor affecting miles traveled seems to be personal income.  Cost of travel also has some affect, and over the 1990’s, the real cost of travel declined, while personal income rose.  

Looking ahead, we could  expect the number of drivers to increase with population.  Commuting is likely to remain one of the longer trips, but it is difficult to determine how much the average miles per driver might change.  For example, as the baby boomers age, they may continue working longer, but they may re-locate and find work closer to their homes at the same time as younger workers continue moving out.  

## MPG: Efficiency Improvements Leveled Off

**Fleet**
**Weight**
**4060 lbs**

**Fleet**
**Weight**
**3271 lbs**

**Fleet**
**Weight**
**3612lbs**

**Note: LDV weights are for 1975, 1985, 1995, 2004**
**Source: U.S EPA, Light-Duty Automotive and Fuel Economy Trends: 1975-2004, April 2004.**

**Fleet**
**Weight**
**4066 lbs**

**Notes:**
Corporate Average Fuel Economy (CAFE) standards (established in the Energy Policy and Conservation Act of 1975) and high fuel prices resulted in large improvements in vehicle efficiencies for almost 10 years in the late seventies and early eighties.  Car efficiencies improved about 50 percent.

## MPG: Historical Efficiencies Affected Demand Relatively Quickly

**Source: Department of Transportation, FHA, Highway Statistics 2001, Table VM-1.**

**Notes:**
The improved vehicle efficiency resulted in falling gasoline demand from 1979 through 1982.

Then from the mid 1980’s, other factors, such as buyers shifting to minivans, SUV’s and heavier and higher performance automobiles, countered engine efficiency improvements.  Light-duty-vehicle efficiency actually declined since the late 1980’s for the entire fleet.  

The graph illustrates that efficiency improvements can affect demand in less than 10 years.  During the early period from 1978 to 1982 shown to the left of the dotted line, vehicle miles traveled was basically flat, and gasoline consumption declined as car efficiencies improved.  Even after 1982, gasoline consumption growth was small as car efficiencies continued to improve, countering the increasing share of light-duty trucks in the fleet.  

Because vehicles are further along the efficiency curve now, we might not see the dramatic percentage improvements in the future that occurred in the past.  During the late 1970’s and early 1980’s, the fuel efficiency of the new vehicles was between 45% and 55% of the average fleet on the road.  Still, the technology exists to improve fuel economy by over 30%, but will it become economic and be incorporated?

Could we see another period of increasing efficiency?

## MPG: LDV Performance & Weight Countered Efficiency

**Source: U.S EPA, Light-Duty Automotive and Fuel Economy Trends: 1975-2004, April 2004.**

**Notes:**
Before turning towards the future, this graph shows  how both weight increased and performance improved, helping to counter efficiency improvements.  

## MPG: Growing LDV Truck Share of Sales Hindered Fleet Efficiency

**Source: Oak Ridge National Laboratory, Light Vehicle MPG and Market Shares System, Oak Ridge, TN, 2004, Wards AutoInfoBank **

| Jan-May Ward’s Sales |  |  |
| --- | --- | --- |
|  | 2004 | 2005 |
| Cars | 45.5% | 46.2% |
| Light Trucks | 54.5% | 53.8% |

**Notes:**
This slide illustrates perhaps the largest factors hindering light-duty vehicle efficiency improvements -- the dramatic shift from cars to SUVs.  Over half the new light duty vehicle sales are now in the truck category.

Yet, we are seeing some shift this year.  Are the high prices actually causing consumers to turn away from the less energy efficient SUVs?  Or have the SUV producers simply not provided enough market-appeal features this year?  It is too early to know what is behind the slight shift, but interesting to note the coincidental decline this year in truck sales market share after a year of high fuel prices.

## Hybrid Vehicle Sales Picking Up

**Toyota Prius**
**2002 sales 20,119**
**2003 sales 24,627**
**2004 sales 53,991**
**2005 projected sales ~100,000**
**Toyota introducing Hybrid Lexus RX and Highlander**

**Source: Automotive News Market Data Book 2004, 2005 **

**Notes:**
Another hint at consumers’ concern over fuel  prices is the large increase in hybrid sales in 2004 and projected 2005.  Toyota is currently the largest supplier of hybrid vehicles, and its sales doubled in 2004 and are likely to double again in 2005

As a result of this interest, Toyota and other automobile manufacturers are beginning to offer a larger selection of hybrids.  For example, Ford has its Escape (SUV) and Toyota has its Lexus RX and Highlander.    

## Recent Trends European Union-15 & U.S.

**Source: Data Transportation Data Book (ORNL); ACEA (Michael Walsh)**

**Notes:**
While the U.S. was moving to more SUV’s and higher performance vehicles, which resulted in a flat to declining fleet efficiency, Europe has been seeing an improvement in efficiency, which is why I wanted to spend a few minutes discussing what they have done, and what we might learn from the European experience.

Europe, which uses both diesel and gasoline light duty vehicles, has seen improvements in miles per gallon for both kinds of vehicles.  They also have had increased penetration of diesel fuel vehicles.  Since diesel vehicles can be 35% more efficient than gasoline-engine vehicles, this trend has helped to increase the efficiency of the fleet.

But European gasoline vehicles have evolved differently also.  Notice how the gasoline car efficiency for Europe in 1995 was about the same as US car efficiency.  European gasoline cars, however, showed a larger increase in efficiency than U.S. cars.

Europe has had some increase in weight and vehicle performance, but the increased penetration of efficient diesel-fueled light duty vehicles has more than overcome the countering weight and performance increases.    

## European Model

**Goal to reduce demand, carbon dioxide emissions (greenhouse gas) concerns**
**Increased diesel preference over gasoline**
**Fuel savings while preserving performance (35% more efficient than gasoline vehicles)**
**New LDV diesel penetration more than doubled in 6 years:  22% in 1997 to 44% in 2003**
**Tax incentives plus targets**
**High fuel taxes and taxes favoring diesel**
**Purchase incentives for more efficient vehicles**
**Economics favor technology improvements**
**Voluntary industry CAFÉ standards**

**Notes:**
Europe’s vehicle evolution, particularly in recent years, has been driven by a desire to reduce demand, which helps them to address the carbon dioxide (CO2) emission concerns.

The move to diesel-fueled vehicles has allowed them to achieve fuel savings without sacrificing performance.  However, Europe has less stringent particulate and nitrogen oxide emission requirements.

Europe also put large tax incentives in place both on fuel and vehicles to encourage using diesel over gasoline.  The tax on diesel fuel is significantly less than on gasoline in many European countries.  

The European automobile industry also has been working towards voluntary CAFÉ standards, but such activities seem unlikely to occur in the United States because of a much different competitive market structure.  

## Diesel PM and NOx Standards Higher in U.S. than Europe

**Source: Michael Walsh, *****Motor Vehicle Pollution Controls*****, European Conference of Ministers of Transport, January 2000**

**Notes:**
This chart illustrates the extent to which European and U.S. emissions standards differ.  

However, technology is within reach to meet U.S. standards, so one barrier to U.S use of light-duty diesel vehicles may soon be removed.

## European Preference for Diesel Grew Quickly since Late 1990s 

**Source: ACEA  **_[www.acea.be](http://www.acea.be/)__ _

**Notes:**
This slide illustrates the rapid penetration of light-duty vehicles in recent years.  European new car registrations went from just over 20% in the mid 1990’s to about half of the new car sales today. 
- New vehicle registrations showed new diesel vehicles exceeding 40% of new light-duty vehicles.  
- This compares to 1-2% in the United States.

This shift from gasoline to diesel has been occurring over many years, which set the stage for the recent surge over the last seven years.  

## EU-15 Demand Mix Projected to See Declining Gasoline Demand

**Source: History IEA; Forecast Purvin & Gertz**

**Notes:**
That movement to light duty diesel vehicles resulted in European diesel fuel demand overtaking gasoline demand after 1995.  

Diesel demand is expected by many forecasters to continue to grow, while gasoline demand will continue to decline.

## Factors Affecting LDV Efficiency (2003)

**EU**

**U.S.**

**Diesel  Share of New Sales**

**LD Truck  Share of New Sales**

**Source: ACEA, ORNL Transportation Data Book, CCFA**

**Notes:**
So comparing with the U.S., while Europe has moved to a car fleet that has been increasing the share of high-energy-efficient diesels, with little SUV penetration, the U.S. has been shifting toward a less efficient vehicle mix.

## U.S. & EU Trends Affecting Efficiency

|  | Values in 2002 |  | Percent Change 1995-2002 |  |
| --- | --- | --- | --- | --- |
|  | EU-15 | U.S. | EU-15 | U.S. |
| Population (Millions) | 380.4 | 288.4 | 2.0% | 8.3% |
| LDVs per
1000 Population | 488 | 766 | 14.8% | 5.5% |
| Vehicle Weight (pounds) | 2,677 | 3,951 | 10.3% | 9.4% |
| Fuel Economy (MPG) | 35.6 | 24.7 | 15.2% | -0.8% |

**Sources: ACEA, ORNL Transportation Data Book, EPA Automotive and Fuel Technology Trends 75-04, Michael Walsh**

**Notes:**
A few more comparisons are helpful to understand similarities and differences with Europe.

U.S. population is growing more rapidly, implying a more rapid increase in drivers.

Our vehicles available per driver is much higher, but note that Europe’s growth in vehicles per capita is much higher than in the U.S.  

U.S. driving conditions and market interests have resulted in a heavier vehicle fleet, but again note that growth in heavier vehicles in Europe has been strong.

The switch to diesel from gasoline in Europe has resulted in a significant improvement in efficiency, while the U.S. traded away underlying efficiency gains with weight and performance.

## Factors Improving Efficiency

**Europe (EU-15)**
**Diesel vehicle share growth**
**Commitment  to CO2 reduction**
**Voluntary CAFE by manufacturers**
**High fuel taxes, but lower taxes for diesel**
**Technology improvements both diesel and gasoline**
**Less stringent PM & NOx standards**

**U.S.**
**Small increase in light truck  CAFE**
**Recent fuel cost increases**
**Technology improvements in gasoline vehicles**
**Hybrid interest**

**Notes:**
To summarize the differences between Europe and the U.S. this slide highlights the factors working towards higher efficiencies in the two areas.

## Factors Decreasing Efficiency

**Europe**
**Increasing vehicle size and performance**
**Increase in cost for efficiency improvements**

**U.S.**
**Increase in vehicle performance and size**
**Increased  share of LD trucks**
**Low fuel tax and few efficient vehicle purchase incentives**
**Manufacturers’  opposition to CAFE**
**Small LD diesel market, strict NOx and PM**

**Notes:**
And this slide highlights the factors working against total stock efficiency in the two areas.

## EU Lessons? 

**Diesel  may play larger role in the U.S. future**
**Environmental emissions being overcome**
**Consumer issues  overcome in Europe, and could become a positive relative to gasoline**
**But fuel cost advantage may diminish**
**Basic population growth and car-dependency issues will make slowing U.S. demand a larger challenge than in EU.**
**U.S. would need to improve efficiency on large fraction of new vehicles to see impact**
**Europe’s diesel momentum in 1995 helped produce a 15% improvement in MPG in 7 years**
**Would  unlikely be achievable  in the US during next 7 years**

**Notes:**
There are some lessons here.  The most important is that diesel could play a larger role in the U.S. in the future.  Most experts agree the diesel emission issues will be overcome.  Also, the diesel consumer acceptance barriers seem to have been overcome.  

However, this year’s diesel prices are a reminder that, while diesel fuel cost has historically been lower than gasoline, it could lose that advantage in the future.  

The U.S. economy is centered on spread-out housing and car dependency, which makes slowing U.S. demand a larger challenge than in Europe.

Furthermore, we should not expect the kind of efficiency improvement Europe saw in the last few years because they were already on their way to replacing less efficiency gasoline vehicles with gasoline.  That momentum simply accelerated in recent years. 

## U.S. Future: Three Cases

**Reference Case:  Continuing trends**
**CAFÉ: Evolutionary (not revolutionary) changes **
**Technology changes**
**Affects all vehicles in small ways**
**CAFÉ + Hybrid/Diesel: Extreme case**
**Early, high penetration of hybrid and diesel vehicles**
**Affects small number of vehicles in large way**
**Illustrates practical limits to impacts on demand**

**Notes:**
Now we turn back to the U.S. to explore two high efficiency scenarios relative to a Reference Case.  

The Reference Case is a continuation of current trends. 

Two high efficiency variations will be will be explored.   The first is the CAFÉ Case that was developed in a recent study (December 2004) by the National Commission on Energy Policy (NCEP, a nongovernmental privately-funded entity), called Ending the Energy Stalemate: A Bipartisan Strategy to Meet America’s Energy Challenges.   This case relies on technology changes to existing engines and vehicles without changes in SUV mix or hybrid/diesel penetration from the Reference Case.  These changes affect all new vehicles in small ways.

The second case is an extreme case that forces high penetration of hybrid and diesel-fueled vehicles into the market.  This case affects a small, but growing share of vehicles sold each year, which have very large efficiency improvements.

We will explore the magnitude of the impact of the changes in these two cases, including the countering response of drivers to drive more when fuel costs go down because of improved fuel economy, and how fast the impact can be seen.

## Reference Case: Future MPG Improvements Hindered by Continuing Shift Towards Trucks

**Source: EIA, Annual Energy Outlook 2005**

**Notes:**
The Reference Case continues to see increased penetration of light trucks.

However, cost-effective technology improvements allow for some improvement of efficiencies in both the car and light truck categories.

Still, the light truck penetration with its lower efficiencies keeps the overall light duty vehicle stock efficiency relatively flat.

## New Vehicle MPG Profiles

**Source: EIA**

**Notes:**
The chart on the left shows new car efficiencies and the graph on the right, new light-duty-truck efficiencies.  The roughly horizontal lines are the efficiencies in the Reference Case, which show some improvement.  

The CAFÉ Case has cars improving 30 percent by 2015 over 2005, with the changes beginning in 2010.  The CAFÉ + Hybrid/Diesel Case has cars improving 45% by 2015, with changes beginning as early as 2008.  

Light-duty trucks improve 36% by 2015 over 2005 in the CAFE Case, and 58% in the CAFÉ + Hybrid/Diesel Case.

Note already that the CAFÉ + Hybrid/Diesel Case is starting to affect new car sales earlier than is probably feasible.

## CAFÉ+Hybrid/Diesel Case Far Exceeds Even Europe’s High Diesel Penetration Rates

**Source: EIA**

**Notes:**
This chart shows the percent of new light-duty -ehicle sales that hybrids and diesel-fueled vehicles represent.  

The CAFÉ + Hybrid/Diesel Case clearly has a much higher penetration, which was the purpose of the case.  But the rate of penetration here even exceeds Europe’s fairly rapid penetration of diesel-fueled vehicles in recent years.  

While such an extreme case may not be probable, it helps to illustrate how much of an effect one might see under such circumstances to compare with the other cases. 

## MPG: New Cars Represent 7.5%-8.0% of Total Stock Each Year, But Are Driven Slightly More Than Older Cars

| Fleet Age and Use Distribution |  |  |
| --- | --- | --- |
| Vehicle Age | Fleet Share | Percent Miles Driven |
| 0-2 yrs | 15% | 21% |
| 3-5 yrs | 22% | 25% |
| 6-10 yrs | 28% | 29% |
| 11 or more | 35% | 25% |

**Source: Summary of  Travel  Trends, 2001 National Household Travel Survey, ORNL**

**Notes:**
Even with the high penetration of hybrid and diesel vehicles in the CAFE + Hybrid/Diesel Case, the rate of turnover of the fleet will slow the impact on actual demand.

Each year, new vehicle sales only represent about 7.5%-8.0% of the total vehicle stock.  This chart illustrates that about 65% of the vehicle stock is 10 years old or less, but about 75% of the miles driven are on vehicles 10 years old or less.  That is, people tend to drive newer vehicles more than older vehicles.

Still, it takes time for new vehicles to represent a large share of the vehicle fleet and miles driven.

## Even Fast Penetration of High Efficiency Vehicles Can’t Change Total Stock Quickly

**Source: EIA**

**Notes:**
The slow speed with which new vehicles can affect demand is illustrated in this slide.

The high penetration CAFÉ + Hybrid/Diesel Case is used to show this effect.  The efficiency improvements of the cars and trucks are illustrated, along with the efficiency of the total stock of light-duty vehicles.  

The total stock doesn’t begin to turn up until about 2010, and even by 2020, the total stock has not achieved the efficiency of even the new trucks.

## Lower Costs May Result in More Miles Driven (3% Rebound Effect)

**Source: EIA**

**Notes:**
While efficiency is improving, drivers counter some of that efficiency gain by driving these higher efficiency vehicles more because of the lower fuel costs per mile. 

To illustrate this, we will compare the miles driven in the Reference Case in 2020 with those in the CAFÉ Case.  The increase in miles driven in the Reference Case from 2005 is about 40% due to the increase in population, represented by the orange area.  About 60% of the increase in miles is driver behavior, influenced mainly by increasing personal income.  

When compared to the CAFÉ Case in 2020, we see a slight increase in the miles over the Reference Case due to changes in driver behavior.  This increase, sometimes called the rebound effect, represents about a 3% increase in miles driven over the Reference Case.

However, despite this rebound effect, the next slide will show that the net change in light-duty fuel use is significant.

## By 2020, CAFE Case Requires 40% Less Additional Supply Than Reference

**2.9 MMB/D**

**1.7**

**0.8**

_**2005-2020**_

**Source: EIA**

**Notes:**
First note that the CAFÉ Case only begins to manifest a difference from the Reference Case after 2010.  The CAFÉ + Hybrid/Diesel Case shows results earlier, but recall that the assumption in this situation allowed fairly high penetration to begin earlier than is likely feasible.  

The light-duty fuel use in the CAFÉ Case, which had little penetration of hybrids and diesels, is 40% lower than in the Reference Case.  

That is, the Reference Case would require access to at least another 4 MMB/D of new capacity, while the CAFÉ Case would require at least 2.3 MMB/D of new capacity.  

The CAFÉ + Hybrid/Diesel Case has flattened over this period, but still requires an increase in capacity, perhaps 1 MMB/D.  Keep in mind that this case required extreme assumptions to reach this point.  Furthermore, since the penetration of hybrids and diesels leveled out at a fairly constant percentage in the scenario, demand beyond this time period begins climbing again.  

So the 2 things to note from this chart are that significant change in overall demand is possible without having to resort to an extreme situation; but it won’t happen quickly.  Furthermore, the types of changes shown, even in the CAFÉ Case, would likely require policy changes to happen this quickly.

## Implications for Refinery Investments

**It takes 10 years to begin to see effects of significant vehicle efficiency changes.**
**Without much hybrid or diesel penetration, within 15 years, technology could reduce need for new capacity by 30-40%.**
**With increased hybrid and diesel penetration, demand growth could be further slowed.**
**But stopping demand growth soon requires unlikely to impossible vehicle/fuel changes. **
**Furthermore, policy changes likely would be required to achieve even the modest CAFÉ Case.**

**Notes:**
The main points from this presentation that would be of interest for refinery capacity planning are highlighted on this slide.

Significant volume effects from shifts in light-duty vehicle efficiency will not be seen quickly.  

Even without hybrid or diesel fuel-vehicle penetration, technology changes alone could slow demand from the Reference Case, reducing the need for capacity by perhaps 30%-40%.  

But faster penetration of very high efficiency vehicles like hybrids and diesel-fueled vehicles could increase slow demand growth further.

Stopping demand growth soon is not likely.

To achieve the full impact of the technology changes shown in the CAFE Case, policy changes likely would be needed.  As indicated in Congressional testimony* provided by Mr. K.G. Duleep, an expert in vehicle technology, available technology improvements could cost-effectively improve efficiency by 24-26%; however under free market conditions, probably half of that efficiency would be countered by consumers buying larger, higher performance cars.

* Testimony before the House Science Committee, February 5, 2005.