Light-Duty Automotive Technology and 

Fuel Economy Trends: 

1975 through 2007 
Light-Duty Automotive Technology and 


Fuel Economy Trends: 


1995 through 2007


Compliance and Innovative Strategies Division


and


Transportation and Climate Division


Office of Transportation and Air Quality


U.S. Environmental Protection Agency 

NOTICE 

This technical report does not necessarily represent final EPA decisions or 


positions. It is intended to present technical analysis of issues using data 


that are currently available. The purpose in the release of such reports is to 


facilitate the exchange of technical information and to inform the public of 


technical developments.


EPA420-R-07-008


September 2007

Table of Contents 

Page

Number 

I. Executive Summary ........................................................................................................... i

II. Introduction.........................................................................................................................1 

III. General Car and Truck Trends ...........................................................................................6 

IV. Trends by Vehicle Type, Size and Weight........................................................................18

V. Technology Trends .......................................................................................................... 36

VI. Marketing Groups ............................................................................................................ 67 

VII. Characteristics of Fleets Comprised of Existing Fuel-Efficient Vehicles ........................77 

VIII. References . . . ............................................................................................................... 87 

Appendixes . . . . . . ..................................................................................................... A-Q 
Table of Contents, continued

Appendixes

APPENDIX A - Database Details and Calculation Methods 

APPENDIX B - Model Year 2007 Nameplate Fuel Economy Listings 

APPENDIX C - Fuel Economy Distribution Data 

APPENDIX D - Data Stratified by Vehicle Type 

APPENDIX E - Data Stratified by Vehicle Type and Size 

APPENDIX F - Car Data Stratified by EPA Car Class 

APPENDIX G - Data Stratified by Vehicle Type and Weight Class 

APPENDIX H - Data Stratified by Vehicle Type and Drive Type 

APPENDIX I - Data Stratified by Vehicle Type and Transmission Type 

APPENDIX J - Data Stratified by Vehicle Type and Cylinder Count 

APPENDIX K - Data Stratified by Vehicle Type, Engine Type and Valves Per Cylinder 

APPENDIX L - Data Stratified by Vehicle Type and Marketing Group 

APPENDIX M - Fuel Economy by Marketing Group, Vehicle Type and Weight Class 

APPENDIX N - Fuel Economy and Ton-MPG by Marketing Group, Vehicle Type and Size 

APPENDIX O - MY2007 Fuel Economy by Vehicle Type, Weight and Marketing Group 

APPENDIX P - Data Stratified by Marketing Group and Vehicle Type 

APPENDIX Q - Characteristics of Fleets Comprised of Fuel Efficient Vehicles 

I. Executive Summary 

Introduction 

This report summarizes key trends in fuel economy and technology usage related to 

model year (MY) 1975 through 2007 light-duty vehicles sold in the United States. Light-duty

vehicles are those vehicles that EPA classifies as cars or light-duty trucks (sport utility vehicles, 

vans, and pickup trucks with less than 8500 pounds gross vehicle weight ratings). 

Since 1975, overall new light-duty vehicle fuel economy has moved through four phases: 

1. a rapid increase from 1975 through the early 1980s, 

2. a slower increase until reaching its peak in 1987, 

3. a gradual decline until 2004, and 

4. an increase in 2005 and 2006, with 2007 levels projected to be similar to 2006. 

The projected average MY2007 light-duty vehicle fuel economy, based in large part on 

pre-model year sales projections from automakers, is 20.2 miles per gallon (mpg). The MY2006 

value is also 20.2 mpg. There is greater confidence in the MY2006 value as the database for

2006 includes formal sales data for about 70% of the MY2006 fleet. The 20.2 mpg value for 

model years 2006 and 2007 represents a 0.9 mpg, or 5%, increase over the 19.3 mpg value for 

2004, which was the lowest fuel economy value since 1980. 

The fuel economy values in this report are either adjusted (ADJ) EPA “real-world”

estimates provided to consumers, or unadjusted EPA laboratory (LAB) values. Most of the data 

is presented in adjusted values. Either adjusted or laboratory fuel economy may be reported as 

city, highway, or, most commonly, as composite (combined city/highway, or COMP). In 2006, 

EPA revised the methodology by which EPA estimates adjusted fuel economy to better reflect 

changes in driving habits and other factors that affect fuel economy such as higher highway 

speeds, more aggressive driving, and greater use of air conditioning. This is the first report in

this series to reflect this new real-world fuel economy methodology, and every adjusted fuel 

economy value in this report for 1986 and later model years is lower than previously reported. 

To reflect the fact that these changes did not occur overnight, these new downward adjustments 

are phased in, gradually, beginning in 1986, and for 2005 and later model years the new adjusted 

composite (combined city/highway) values are, on average, about 6% lower than under the 

methodology used by EPA in previous reports in this series. See Appendix A for more details. 

Because the underlying methodology for generating unadjusted laboratory fuel economy 

values has not changed since this series began in the mid-1970s, they provide an excellent basis 

for comparing long-term fuel economy trends from the perspective of vehicle design, apart from

the factors that affect real-world fuel economy that are reflected in the adjusted fuel economy 

values. For 2005 and later model years, unadjusted laboratory composite fuel economy values 

are, on average, about 25% greater than adjusted composite fuel economy values. 

The Department of Transportation’s National Highway Traffic Safety Administration 

(NHTSA) has the overall responsibility for the Corporate Average Fuel Economy (CAFE) 

program. For 2007, the CAFE standards are 27.5 mpg for cars and 22.2 mpg for light trucks. 

EPA provides laboratory composite 55/45 fuel economy data, along with alternative fuel vehicle 

credits and test procedure adjustments, to NHTSA for CAFE enforcement. Accordingly, current

NHTSA CAFE values are a minimum of 25% higher than EPA adjusted fuel economy values. 

i 
Importance of Fuel Economy

Fuel economy continues to be a major area of public and policy interest for several 

reasons, including: 

1. Fuel economy is directly related to energy security because light-duty vehicles 

account for approximately 40 percent of all U.S. oil consumption, and much of 

this oil is imported. 

2. Fuel economy is directly related to the cost of fueling a vehicle and is of great 

interest when crude oil and gasoline prices rise. 

3. Fuel economy is directly related to emissions of greenhouse gases (i.e., carbon 

dioxide). Light-duty vehicles contribute about 20 percent of all U.S. carbon 

dioxide emissions. 

Characteristics of Light Duty Vehicles for Four Model Years 

1975 1987 1997 2007

Adjusted Fuel Economy (mpg) 13.1 22.0 20.1 20.2 

Weight (lbs.) 4060 3221 3727 4144 

Horsepower 137 118 169 223 

0 to 60 Time (sec.) 14.1 13.1 11.0 9.6 

Percent Truck Sales 19% 28% 42% 49% 

Percent Front-Wheel Drive 5% 58% 56% 51% 

Percent Four-Wheel Drive 3% 10% 19% 28% 

Percent Multi-Valve Engine - - 40% 70% 

Percent Variable Valve Timing - - - 59% 

Percent Cylinder Deactivation - - - 8% 

Percent Turbocharger - - 0.5% 3% 

Percent Manual Transmission 23% 29% 14% 8% 

Percent Continuously Variable Trans - - - 7% 

Percent Hybrid - - - 2.2% 

Percent Diesel 0.2% 0.3% 0.1% 0.1% 

ii 
Highlight #1: Fuel Economy Increases in 2005 and 2006 Reverse the Long-Term Trend of

Declining Fuel Economy From 1987 Through 2004. 

Overall fuel economy increased 0.9 mpg, or 5%, from 19.3 mpg in MY2004 to 20.2 mpg

in MY2006. Fuel economy for both cars and trucks is projected to increase for MY2007.

However, due to a slight increase in projected truck market share, the overall value for

MY2007 is also projected to be 20.2 mpg. The increases in 2005 and 2006 are the first 

consecutive annual increases in fuel economy since the mid-1980s. This reverses a long

trend of slowly declining fuel economy since the 1987 peak. 

Since 1975, the fuel economy of the combined car and light truck fleet has moved 

through several phases: (1) a rapid increase from 1975 to the early 1980s, (2) a slow increase 

extending to the fuel economy peak of 22.0 mpg in 1987, (3) a gradual decline from the peak to 

19.3 mpg in 2004, and (4) consecutive annual increases in 2005 and 2006, growing to 20.2 mpg 

in 2006, with the same value projected for 2007. 

The 20.2 mpg value for model years 2006 and 2007 is 1.8 mpg below the peak of 22.0 

mpg in MY1987. But, it is important to note that two-thirds of this difference is due to the new 

methodology for calculating adjusted fuel economy values that is gradually phased in over the 

1986 to 2005 timeframe. Based on the laboratory composite 55/45 fuel economy values, which 

are not affected by the new methodology for calculating adjusted fuel economy values, the 

MY2006 and MY2007 value of 25.3 mpg is 0.6 mpg below the peak of 25.9 mpg in 1987. 

MY2007 cars are projected to average 23.4 mpg and MY2007 light trucks are estimated 

to average 17.7 mpg, both 0.1 mpg higher than MY2006. Most of the increase in overall fuel 

economy since 2004 has been due to higher truck fuel economy, as truck fuel economy has 

increased by 1.0 mpg since 2004 while car fuel economy has increased by 0.3 mpg (prior to 

MY2007, the overall fleetwide fuel economy increase had also been aided by a slightly higher 

car market share). The recent increase in truck fuel economy is due, in part, to higher truck 

CAFE standards, which have risen from 20.7 mpg in 2004 to 22.2 mpg in 2007. 

Adjusted Fuel Economy by Model Year 

(Annual Data) 

Adjusted MPG

30

1970 1975 1980 1985 1990 1995 2000 2005 2010 

Cars

Trucks 

Both 

25 

20 

15 

10 

iii 
Highlight #2: Trucks Continue To Represent About Half of New Vehicle Sales. 

Sales of light trucks, which include sport utility vehicles (SUVs), vans, and pickup trucks, 

have accounted for about 50 percent of the U.S. light-duty vehicle market since MY2002.

After two decades of constant growth, light truck market share has been relatively stable

for the last six years. 

Historically, growth in the light truck market was primarily driven by the explosive 

increase in the market share of SUVs. The SUV market share increased from less than 10 

percent of the overall new light-duty vehicle market in MY1990 to about 30 percent of vehicles 

built each year since 2003. By comparison, market shares for both vans and pickup trucks have 

declined slightly since 1990. The increased overall market share of light trucks, which in recent 

years have averaged 5-7 mpg lower than cars, accounted for much of the decline in fuel economy 

of the overall new light-duty vehicle fleet from MY1987 through MY2004. 

Sales Fraction by Vehicle Type 

(Annual Data) 

0% 

20% 

40% 

60% 

80% 

100% 

Market Share

 Pickup

 Van

 SUV

 Car 

1975 1980 1985 1990 1995 2000 2005 

Model Year 

iv 
Highlight #3: Technological Innovation in 2005 and 2006 Was Utilized for Higher Fuel

Economy, Reversing the Long-Term Trend of Increasing Vehicle Attributes Such as

Weight and Performance. 

Automotive engineers are constantly developing more advanced and efficient vehicle

technologies. From 1987 through 2004, on a fleetwide basis, this technology innovation

was utilized to support market-driven attributes other than fuel economy, such as vehicle

weight (which supports vehicle content and features), performance, and utility. This 

long-term trend was reversed in model years 2005 and 2006, as technology was used to

increase fuel economy by 0.9 mpg. The current projection for MY2007 is an increase in

market-driven attributes with no change in fuel economy, but this is subject to change

when EPA obtains formal 2007 sales data. 

Vehicle weight and performance are two of the most important engineering parameters 

that determine a vehicle=s fuel economy. All other factors being equal, higher vehicle weight

(which supports new options and features) and faster acceleration performance (e.g., lower 0-to60 mile-per-hour acceleration time), both decrease a vehicle=s fuel economy. Average vehicle

weight and performance had increased steadily from the mid-1980s through 2004. 

Average light-duty vehicle weight dropped in both model years 2005 and 2006, with a

slight increase in weight of cars more than offset by a larger decrease in truck weight and a

decrease in truck market share. Average weight is projected to grow again in MY2007 to the

highest level ever. Average fleetwide performance was essentially unchanged in both 2005 and

2006, but is also projected to increase to record levels in MY2007. The validity of these

projections will be confirmed when EPA obtains formal vehicle sales data after the end of

MY2007. 

Weight and Performance

(Annual Data) 

3000 

3500 

4000

4500

Weight (lbs.) 

9 

10 

11 

12 

13 

14 

15

0 to 60 Time (sec.) 

Weigh 

0 to 60 Time 

1975 1980 1985 1990 1995 2000 2005

Model Year 

v 
Marketing Group Fuel Economy for Three Model Years

Highlight #4: Differences Between Marketing Group Fuel Economies are Narrowing. 

In 1987, when industry-wide fuel economy peaked, some major marketing groups had

average fuel economies 6 to 8 mpg higher than other top marketing groups. For 

MY2007, the maximum difference between major marketing groups is estimated to be 4.6

mpg, with a typical difference between higher and lower fuel economy marketing groups

being 3 to 4 mpg. 

For MY2007, the eight highest-selling marketing groups (that account for over 95 

percent of all sales) fall into three fuel economy groupings: Honda, Toyota, and Hyundai-Kia

(HK) have estimated fuel economies of 22.7 to 22.9 mpg; Volkswagen and Nissan have 

projected fuel economies of 20.6 to 21.4 mpg; and General Motors, Ford, and DaimlerChrysler 

have estimated fuel economies of 18.3 to 19.4 mpg. Note that these adjusted fuel economy 

values for marketing groups can not be directly compared to those in last year’s report, since this 

year’s report uses the new methodology where adjusted fuel economy values since 2005 are, on 

average, about 6% lower than in previous reports. 

Each of these marketing groups has lower average fuel economy today than in 1987. 

Since then, the differences between marketing group fuel economies have narrowed 

considerably, with some of the higher mpg marketing groups in 1987 showing larger fuel 

economy decreases since 1987. Only one marketing group, Toyota, shows a slight increase in 

average fuel economy since 1997. For MY2007, Volkswagen is the only one of the eight

highest-selling marketing groups to have a truck market share of less than 40 percent. 

 Marketing Group Fuel Economy for Three Model Years 

Adjusted Composite MPG 

30 

25 

20 

15 

10 

5 

0 

Honda Toyota HK VW Nissan GM Ford DC

2007 1997 1987 

vi 
Important Notes With Respect to the Data Used in This Report 

Most of the fuel economy values in this report are a single adjusted composite (combined 

city/highway) fuel economy value, based on the real-world estimates for city and highway fuel 

economy provided to consumers on new vehicle labels, in the EPA/DOE Fuel Economy Guide,

and in EPA=s Green Vehicle Guide. 

It is important to note that EPA revised the methodology for estimating real-world fuel 

economy values in December 2006. This is the first report in this series to reflect this new realworld fuel economy methodology, and every adjusted (ADJ) fuel economy value in this report 

for 1986 and later model years is lower than given in previous reports in this series. 

Accordingly, adjusted fuel economy values for 1986 and later model years should not be 

compared with the corresponding values from previous reports. These new downward 

adjustments are phased in, linearly, beginning in 1986, and for 2005 and later model years the 

new adjusted composite (combined city/highway) values are, on average, about 6% lower than 

under the methodology previously used by EPA. See Appendix A for more in-depth discussion 

of this new methodology and how it affects both the adjusted fuel economy values for individual 

models and the historical fuel economy trends database. 

In some tables and figures in this report, a single laboratory composite (combined 

city/highway) 55/45 value is also shown. Because the underlying methodology for generating 

and reporting laboratory fuel economy values has not changed since this series began in the mid1970s, these laboratory fuel economy values provide an excellent basis for comparing long-term

fuel economy trends from the perspective of vehicle design, apart from the factors that affect 

real-world fuel economy that are reflected in the adjusted fuel economy values. For 2005 and 

later model years, laboratory composite fuel economy values are, on average, about 25% greater 

than adjusted composite fuel economy values. 

Formal Corporate Average Fuel Economy (CAFE) compliance data as reported by the 

Department of Transportation’s National Highway Traffic Safety Administration (NHTSA) does 

not correlate precisely with either the adjusted or laboratory fuel economy values in this report. 

While EPA’s laboratory composite 55/45 fuel economy data forms the cornerstone of the CAFE 

compliance database, NHTSA must also include credits for alternative fuel vehicles and test 

procedure adjustments (for cars only) in the official CAFE calculations. Accordingly, NHTSA

CAFE values are at least 25% higher than EPA adjusted fuel economy values for model years 

2005 through 2007. 

In general, car/truck classifications in this database parallel classifications made by 

NHTSA for CAFE purposes and EPA for vehicle emissions standards. However, this report

relies on engineering judgment, and typically there are a few cases each model year where the 

methodology used for classifying vehicles for this report results in differences in the 

determination of whether a given vehicle is classified as a car or a light truck. See Appendix A

for a list of these exceptions. 

 The data presented in this report were tabulated on a model year basis, but many of the 

figures in this report use three-year moving averages that effectively smooth the trends, and 

these three-year moving averages are tabulated at the midpoint. For example, the midpoint for 

model years 2005, 2006, and 2007 is MY2006. Figures are based on annual data unless

otherwise noted. 

vii 
All average fuel economy values were calculated using harmonic, rather than 

arithmetical, averaging, in order to maintain mathematical integrity. See Appendix A. 

The EPA fuel economy database used to generate the fuel economy trends database in 

this report was frozen in February 2007, yielding additional data beyond that used in last year’s

report for model years 2004 through 2007, although additional data for MY2006 was added in 

April 2007. 

Through MY2005, the fuel economy, vehicle characteristics, and sales data used for this 

report were from the formal end-of-year submissions from automakers obtained from EPA’s fuel 

economy database that is used for CAFE compliance purposes. Accordingly, values for all

model years up to 2005 can be considered final. 

For MY2006, the data used in this report is based on a database where about 70% of the

total sales are from formal end-of-year CAFE submissions by automakers, and about 30% are 

from confidential pre-model year sales projections submitted to the Agency by the automakers, 

with these latter projections updated based on actual 2006 sales data reported in trade

publications. EPA has a high level of confidence in the data for MY2006, given that 70% of the

2006 data is based on actual CAFE reports. It is noteworthy that the 25.3 mpg laboratory fuel 

economy value for MY2006 in this report is 0.7 mpg higher than the projected 24.6 mpg 

laboratory fuel economy value for MY2006 in the 2006 report. This suggests that sustained,

higher gasoline prices have led to actual 2006 sales that differ from the projected 2006 sales 

provided to EPA by automakers in 2005. 

For MY2007, EPA has exclusively used confidential pre-model year sales projections, 

updated based on actual sales for the first 7 months of model year 2007 (October 2006 through 

April 2007). MY2007 projections are more uncertain, particularly given the changes in the 

automotive marketplace driven by higher fuel prices and other factors. For model years 1998 

through 2005, the final laboratory fuel economy values for a given model year have varied from

0.4 mpg lower to 0.3 mpg higher compared to original estimates for the same model year that 

were based exclusively on projected sales. 

viii 
For More Information 

Light-Duty Automotive Technology and Fuel Economy Trends: 1975 through 2007 

(EPA420-R-07-008) is available on the Office of Transportation and Air Quality=s (OTAQ) Web 

site at: 

http://www.epa.gov/otaq/fetrends.htm 

Printed copies are available from the OTAQ library at: 

U.S. Environmental Protection Agency 

Office of Transportation and Air Quality Library 

2000 Traverwood Drive 

Ann Arbor, MI 48105 

(734) 214-4311 

A copy of the Fuel Economy Guide giving city and highway fuel economy data for individual 

models is available at: 

http://www.fueleconomy.gov 

or by calling the U.S. Department of Energy at (800) 423-1363. 

EPA's Green Vehicle Guide providing information about the air pollution emissions and fuel 

economy performance of individual models is available on EPA=s web site at: 

http://www.epa.gov/greenvehicles/ 

For information about the Department of Transportation (DOT) Corporate Average Fuel 

Economy (CAFE) program, including a program overview, related rulemaking activities, 

research, and summaries of individual manufacturer=s fuel economy performance since 1978, 

see: 

http://www.nhtsa.dot.gov/ and click on “Fuel Economy” 

ix 

II. Introduction 

Light-duty automotive technology and fuel economy trends are examined here, as in the 

preceding reports in this series [1-33]*

, using the latest and most complete EPA data available. 

When comparing data in this and previous reports, please note that revisions are made for 

some prior model years for which more complete and accurate sales and fuel economy data have 

become available. In addition, changes have been made periodically in the way EPA calculates 

adjusted fuel economy values which means it is not appropriate to compare adjusted fuel 

economy values from this report with others in this series. 

The EPA fuel economy database used to generate the fuel economy trends database in 

this report was frozen in February 2007, yielding additional data beyond that used in last year’s

report for model years 2004 through 2007, though additional data for MY2006 was added in 

April 2007. 

Through MY2005, the fuel economy, vehicle characteristics, and sales data used for this 

report were from the formal end-of-year submissions from automakers obtained from EPA’s fuel 

economy database that is used for CAFE compliance purposes. For MY2006, the data used in 

this report is based on a database where about 70% of the total sales are from formal end-of-year 

CAFE submissions by automakers, and about 30% of the total sales are based on confidential 

pre-model year sales projections submitted to the Agency by the automakers, with these latter 

projections updated based on actual 2006 sales data reported in trade publications. For MY2007, 

EPA has exclusively used confidential pre-model year sales projections, updated based on actual 

sales for the first 7 months of model year 2007 (October 2006 through April 2007). 

Accordingly, values for all model years up to 2005 can be considered final. EPA has a 

high level of confidence in the data for MY2006, given that 70% of the 2006 data is based on

actual CAFE reports. MY2007 projections are more uncertain, particularly given the changes in 

the automotive marketplace driven by higher fuel prices and other factors. Over the last several 

years, the final fuel economy values for a given model year have varied from 0.4 mpg lower to 

0.3 mpg higher compared to original estimates for the same model year that were based 

exclusively on projected sales. 

All fuel economy averages in this report are sales-weighted harmonic averages. In prior

reports in this series, up to and including the one for MY2000, the only fuel economy values 

used in this series were the laboratory-based city, highway, and composite (combined 

city/highway) mpg values C the same ones that are used as the basis for compliance with the 

fuel economy 

__________ 

* Numbers in brackets denote references listed in the references section of this report. 

1 
standards and the gas guzzler tax. Since the laboratory mpg values tend to over predict the mpg 

achieved in actual use, adjusted mpg values are used for the Government=s fuel economy 

information programs: the Fuel Economy Guide and the Fuel Economy Labels that are on new 

vehicles and in EPA=s Green Vehicle Guide. 

Starting with the report issued for MY2001, this series of reports has provided fuel

economy trends in adjusted mpg values in addition to the laboratory mpg values. In this way,

the fuel economy trends can be shown for both laboratory mpg and mpg values which can be 

considered to be an estimate of on-road mpg. In the tables, these two mpg values are called 

ALaboratory MPG@ and AAdjusted MPG,@ and abbreviated ALAB@ MPG and AADJ@ MPG. 

Where only one mpg value is presented in this report, it is the Aadjusted composite” fuel 

economy value. This value represents a combined city/highway fuel economy value, and is 

based on equations (see Appendix A) that allow a computation of adjusted city and highway fuel 

economy values based on laboratory city and highway fuel economy test values. 

It is important to note that EPA revised the methodology by which EPA estimates realworld fuel economy values in December 2006. This is the first report in this series to reflect this

new real-world fuel economy methodology, and every adjusted (ADJ) fuel economy value in this 

report for 1986 and later model years is lower than given in previous reports in this series. 

Accordingly, adjusted fuel economy values for 1986 and later model years should not be 

compared with corresponding values from previous reports. These new downward adjustments 

are phased in, linearly, beginning in 1986, and for 2005 and later model years the new adjusted 

composite values are, on average, about 6% lower than under the methodology previously used 

by EPA. See Appendix A for more in-depth discussion of this new methodology and how it 

affects both the adjusted fuel economy values for individual models and the historical fuel 

economy trends database. 

The data presented in this report were tabulated on a model year basis, but many of the 

figures in this report use three-year moving averages which effectively smooth the trends, and 

these three-year moving averages are tabulated at their midpoint. For example, the midpoint for 

model years 2002, 2003, and 2004 is model year 2003 (See Table A-2, Appendix A). Use of 

the three-year moving averages results in an improvement in distinguishing real trends from

what might be relatively small year-to-year variations in the data. 

To facilitate comparison with data in previous reports in this series, most data tables 

include laboratory 55/45 fuel economy values as well as the adjusted city, highway, and 

composite fuel economy values. Presenting both types of mpg values facilitates the use of this 

report by those who study either type of fuel economy metric. 

2 
The fuel economy values reported by the Department of Transportation (DOT) for 

compliance with the Corporate Average Fuel Economy (CAFE) compliance purposes are higher 

than the data in this report for four reasons: 

(1) the CAFE data do not include the EPA real world fuel economy labeling adjustment 

factors for city and highway mpg, 

(2) the CAFE data are increased by special procedures for calculating the fuel economy of 

dedicated alternative fueled vehicles (the fuel economy of all dedicated alternative fuel vehicles 

is calculated based on the assumption that the alternative fuel has a fuel content of .15 gallon of 

fuel) and dual fueled vehicles (a manufacturer's CAFE for each of its fleets can be increased up to 

1.2 mpg). 

(3) the CAFE data reflect adjustments made to account for changes to test procedures for 

cars, and 

(4) there are some slight differences in the way that vehicles are classified as cars and 

trucks for this report compared to the way they are classified by DOT. 

Accordingly, the fuel economy values in this series of reports are always lower than those 

reported by DOT. Table A-6, Appendix A, compares CAFE data reported by DOT with EPAadjusted and laboratory fuel economy data. 

Other Variables 

All vehicle weight data are based on inertia weight class (nominally curb weight plus 300 

pounds). For vehicles with inertia weights up to and including the 3000-pound inertia weight

class, these classes have 250-pound increments. For vehicles above the 3000-pound inertia

weight class (i.e., vehicles 3500 pounds and above), 500-pound increments are used. 

All interior volume data for cars built after model year 1977 are based on the metric used 

to classify cars for the DOE/EPA Fuel Economy Guide. The car interior volume combines the 

passenger compartment and trunk/cargo space. In the Fuel Economy Guide, interior volume is 

undefined for the two-seater class; for this series of reports, all two-seater cars have been

assigned an interior volume value of 50 cubic feet. 

The light truck data used in this series of reports includes only vehicles classified as light 

trucks with gross vehicle weight ratings (GVWR) up to 8500 pounds (lb). Vehicles with GVWR 

above 8500 lb are not included in the database used for this report. Omitting these vehicles 

influences the overall averages for all variables studied in this report. The most recent estimates 

we have made for the impact of these greater than 8500 lb GVWR vehicles was made for model 

year 2001. In that year, there were roughly 931,000 vehicles above 8500 lb GVWR. A 

substantial fraction (42 percent) of the MY2001 vehicles above 8500 lb GVWR were powered 

by diesel engines, and three-fourths of the vehicles over 8500 lb GVWR were pickup trucks. 

Adding in the trucks above 8500 lb GVWR would have increased the truck market share for that 

year by three percentage points. 

3 
Based on a limited amount of actual laboratory fuel economy data, MY2001 trucks with 

GVWR greater than 8500 lb GVWR are estimated to have fuel economy values about 14 percent 

lower than the average of trucks below 8500 lb GVWR. The combined fleet of all vehicles 

under 8500 lb GVWR and trucks over 8500 lb GVWR is estimated to average a few percent less 

in fuel economy compared to that for just the vehicles with less than 8500 lb GVWR. 

In addition to fuel economy, some tables in this report contain alternate measures of 

vehicle fuel efficiency as used in reference 17. 

ATon-MPG@ is defined as a vehicle=s mpg multiplied by its inertia weight in tons. This 

metric provides an indication of a vehicle=s ability to move weight (i.e., its own plus a nominal 

payload). Ton-MPG is a measure of powertrain/drive-line efficiency. Just as an increase in 

vehicle mpg at constant weight can be considered an improvement in a vehicle=s efficiency, an

increase in a vehicle=s weight-carrying capacity at constant mpg can also be considered an 

improvement. 

ACubic-feet-MPG@ for cars is defined in this report as the product of a car=s mpg and its 

interior volume, including trunk space. This metric associates a relative measure of a vehicle=s 

ability to transport both passengers and their cargo. An increase in vehicle volume at constant 

mpg could be considered an improvement just as an increase in mpg at constant volume can be. 

ACubic-feet-ton-MPG@ is defined in this report as a combination of the two previous 

metrics, i.e., a car=s mpg multiplied by its weight in tons and also by its interior volume. It 

ascribes vehicle utility to the ability to move both weight and volume. 

This report also includes an estimate of 0-to-60 mph acceleration time, calculated from

engine rated horsepower and vehicle inertia weight, from the relationship: 

 t = F (HP/WT)

-f 

where the values used for F and f coefficients are .892 and .805 respectively for vehicles with

automatic transmissions and .967 and .775 respectively for those with manual transmissions [34]. 

 Other authors [35, 36, and 37] have evaluated the relationships between weight, horsepower, 

and 0-to-60 acceleration time and have calculated and published slightly different values for the 

F and f coefficients. Since the equation form and coefficients were developed for vehicles with 

conventional powertrains with gasoline-fueled engines, we have not used the equation to

estimate 0-to-60 time for vehicles with hybrid powertrains or diesel engines. Published values 

are used for these vehicles instead. 

The 0-to-60 estimate used in this report is intended to provide a quantitative time "index" 

of vehicle performance capability. It is the authors’ engineering judgment that, given the 

differences in test methods for measuring 0-to-60 time and given the fact that the weight is based 

on inertia weight, use of these other published values for the F and f coefficients would not result

in statistically significantly different 0-to-60 averages or trends. The results of a similar 

calculation of estimated Atop speed@ are also included in some tables. 

4 
Grouping all vehicles into classes and then constructing time trends of parameters of interest, 

like mpg, can provide interesting and useful results. These results, however, are a strong

function of the class definitions. Classes based on other definitions than those used in this report 

are possible, and results from these other classifications may also be useful. 

For cars, vehicle classification as to vehicle type, size class, and manufacturer/origin 

generally follows fuel economy label, Fuel Economy Guide, and fuel economy standards 

protocols; exceptions are listed in Table A-3, Appendix A. In many of the passenger car tables, 

large sedans and wagons are aggregated as "Large," midsize sedans and wagons are aggregated 

as "Midsize," and "Small" includes all other cars. In some of the car tables, an alternative 

classification system is used, namely: Large Cars, Large Wagons, Midsize Cars, Midsize 

Wagons, Small Cars, and Small Wagons with the EPA Two-Seater, Mini-Compact, Subcompact, 

and Compact car classes are combined into the ASmall Car@ class. In some of the tables and 

figures in this report, only four vehicle types are used. In these cases, wagons have been merged 

with cars. This is because the wagon sales fraction for some instances is so small that the 

information is more conveniently represented by combining the two vehicle types. When they 

have been combined, the differences between them are not important. 

The truck classification scheme used for all model years in this report is slightly different 

from that used in some previous reports in this series, because pickups, vans, and sports utility 

vehicles (SUVs) are sometimes each subdivided as ASmall,@ AMidsize,@ and ALarge.@ These truck 

size classifications are based primarily on published wheelbase data according to the following 

criteria: 

Pickup Van SUV

 Small Less than 105" Less than 109" Less than 100" 

Midsize 105" to 115" 109" to 124" 100" to 110" 

Large More than 115" More than 124" More than 110" 

This classification scheme is similar to that used in many trade and consumer 

publications. For those vehicle nameplates with a variety of wheelbases, the size classification 

was determined by considering only the smallest wheelbase produced. The classification of a 

vehicle for this report is based on the authors’ engineering judgment and is not a replacement for 

definitions used in implementing automotive standards legislation. 

Published data is also used for two other vehicle characteristics for which data is not 

currently being submitted to EPA by the automotive manufacturers: (1) engines with variable 

valve timing (VVT) that use either cams or electric solenoids to provide variable intake and/ or 

exhaust valve timing and in some cases valve lift; and (2) engines with cylinder deactivation, 

which involves allowing the valves of selected cylinders of the engine to remain closed under 

certain driving conditions. 

5 
III. General Car and Truck Trends 

Figure 1 and Table 1 depict time trends in car, light truck, and car-plus-light truck fuel 

economy. Also shown on Figure 1 is the fraction of the combined fleet that are light trucks and 

trend lines representing three-year moving averages of the fuel economy and truck sales fraction 

data. Since 1975, the fuel economy of the combined car and light truck fleet has moved 

through several phases: 

1. a rapid increase from 1975 through the early1980s, 

2. a slow increase until reaching its peak in 1987, 

3. a gradual decline until 2004, and 

4. an increase in 2005 and 2006, with 2007 levels projected to be similar to 2006. 

Adjusted Fuel Economy and Percent Truck by Model Year 

(Three Year Moving Average) 

100% 

Moving Avg. 

Yearly Data 

75% 

Cars 

Both 

50% Trucks 

Percent Truck 

25% 

0% 

1970 1975 1980 1985 1990 1995 2000 2005 2010 

Model Year 

Figure 1 

10 

15 

20 

25 

30 

Percent Truck 

Cars 

Trucks 

Pct. Truck 

Both 

Adjusted Composite MPG 

6 
As shown in Table 1, the MY2006 and projected MY2007 fleetwide fuel economy value 

of 20.2 mpg is the highest value since 1996 and is 0.9 mpg higher than the 2004 value of 19.3 

mpg, which was the lowest value since 1980. The back-to-back annual increases in 2005 and 

2006 are the first such increases since the mid-1980s. These increases reverse the longer term 

trend of declining fuel economy since its peak in 1987. Most of the increase in overall fuel 

economy since 2004 is due to higher truck fuel economy, as truck fuel economy has increased by 

1.0 mpg since 2004, while car fuel economy has increased by 0.3 mpg. The 20.2 mpg adjusted 

fuel economy value for 2006-2007 is 1.8 mpg below the peak in 1987, but much of this difference 

is due to the new methodology for calculating adjusted fuel economy values that is phased in over 

the 1986-2005 timeframe. As shown in Table 1, based on laboratory 55/45 fuel economy values, 

the 2006-2007 value of 25.3 mpg is 0.6 mpg lower than the peak of 25.9 mpg in 1987. 

Figure 1 shows that the estimated light truck share of the market, based on the three-year 

moving average trend, has leveled off at about 50 percent. Figure 2 compares laboratory 55/45 

fuel economy for the combined car and truck fleet and the sales fraction for trucks. 

MY2007 cars are estimated to average 23.4 mpg and are near the high end of their mpg 

range since 1996. For MY2007, light trucks are estimated to average 17.7 mpg, their highest 

level since 1991. Fuel economy standards were unchanged for MY1996 through MY2004. In 

2003 DOT raised the truck CAFE standards for 2005-2007, and in 2006 DOT raised the truck 

CAFE standards for 2008-2011.. The recent fuel economy improvement for trucks is likely due, 

in part, to these higher standards. The CAFE standard for cars has not been changed since 1990. 

Truck Sales Fraction vs Fleet MPG by Model Year 

Lab. 55/45 MPG 

10% 20% 30% 40% 50% 60% 70% 

Percent Truck 

Figure 2 

10 

15 

20 

25 

30 

1990 1995 2000 

2007 

2004 

1985 

1975 

1980 

7 
Table 1 

Fuel Economy Characteristics of 1975 to 2007 Light Duty Vehicles 

Cars 

MODEL SALES <---- FUEL ECONOMY ----> TON CU-FT CU-FTYEAR (000) FRAC LAB ADJ ADJ ADJ -MPG -MPG TON-MPG 

55/45 CITY HWY COMP 

1975 8237 .806 15.8 12.3 15.2 13.5 27.6 

1976 9722 .788 17.5 13.7 16.6 14.9 30.2 

1977 11300 .800 18.3 14.4 17.4 15.6 31.0 1780 3423 

1978 11175 .773 19.9 15.5 19.1 16.9 30.6 1908 3345 

1979 10794 .778 20.3 15.9 19.2 17.2 30.2 1922 3301 

1980 9443 .835 23.5 18.3 22.6 20.0 31.2 2136 3273 

1981 8733 .827 25.1 19.6 24.2 21.4 33.1 2338 3547 

1982 7819 .803 26.0 20.1 25.5 22.2 34.2 2419 3645 

1983 8002 .777 25.9 19.9 25.5 22.1 34.7 2476 3776 

1984 10675 .761 26.3 20.2 26.0 22.4 35.1 2482 3776 

1985 10791 .746 27.0 20.7 26.8 23.0 35.8 2553 3884 

1986 11015 .717 27.9 21.2 27.6 23.7 36.2 2598 3899 

1987 10731 .722 28.1 21.2 27.7 23.8 36.2 2584 3872 

1988 10736 .702 28.6 21.4 28.2 24.1 36.9 2631 3963 

1989 10018 .693 28.1 20.9 27.9 23.7 36.8 2591 3977 

1990 8810 .698 27.8 20.5 27.5 23.3 37.1 2528 3984 

1991 8524 .678 28.0 20.5 27.6 23.4 37.0 2540 3970 

1992 8108 .666 27.6 20.0 27.5 23.1 37.4 2534 4071 

1993 8456 .640 28.2 20.3 27.9 23.5 37.7 2580 4098 

1994 8415 .596 28.0 20.0 27.7 23.3 37.9 2554 4108 

1995 9396 .620 28.3 20.0 28.1 23.4 38.3 2584 4171 

1996 7890 .600 28.3 19.8 28.0 23.3 38.3 2572 4186 

1997 8335 .576 28.4 19.8 28.0 23.4 38.3 2565 4168 

1998 7972 .551 28.5 19.7 28.0 23.4 38.7 2565 4210 

1999 8379 .551 28.2 19.4 27.5 23.0 38.7 2531 4237 

2000 9128 .551 28.2 19.3 27.3 22.9 38.6 2534 4246 

2001 8408 .539 28.4 19.4 27.3 23.0 39.1 2551 4280 

2002 8304 .515 28.6 19.4 27.2 23.1 39.3 2561 4311 

2003 7951 .504 28.9 19.5 27.5 23.2 40.0 2582 4378 

2004 7538 .480 28.9 19.3 27.4 23.1 40.3 2601 4464 

2005 8025 .505 29.5 19.6 27.6 23.5 41.0 2677 4590 

2006 8109 .539 29.2 19.4 27.5 23.3 41.5 2660 4646 

2007 7580 .510 29.4 19.5 27.6 23.4 42.6 2689 4762 

8 
Table 1 (continued) 

Fuel Economy Characteristics of 1975 to 2007 Light Duty Vehicles 

Trucks 

MODEL SALES <---- FUEL ECONOMY ----> TON 

YEAR (000) FRAC LAB ADJ ADJ ADJ 

55/45 CITY HWY COMP 

-MPG 

1975 1987 .194 13.7 10.9 12.7 11.6 24.2 

1976 2612 .212 14.4 11.5 13.2 12.2 26.0 

1977 2823 .200 15.6 12.6 14.1 13.3 28.0 

1978 3273 .227 15.2 12.4 13.7 12.9 27.5 

1979 3088 .222 14.7 12.1 13.1 12.5 27.3 

1980 1863 .165 18.6 14.8 17.1 15.8 30.9 

1981 1821 .173 20.1 16.0 18.6 17.1 33.0 

1982 1914 .197 20.5 16.3 19.0 17.4 33.7 

1983 2300 .223 20.9 16.5 19.6 17.8 34.0 

1984 3345 .239 20.5 16.1 19.3 17.4 33.5 

1985 3669 .254 20.6 16.2 19.4 17.5 33.7 

1986 4350 .283 21.4 16.8 20.2 18.2 34.3 

1987 4134 .278 21.6 16.8 20.5 18.3 34.2 

1988 4559 .298 21.2 16.2 20.2 17.9 34.5 

1989 4435 .307 20.9 15.9 19.8 17.6 34.7 

1990 3805 .302 20.7 15.6 19.8 17.4 35.1 

1991 4049 .322 21.3 15.9 20.3 17.8 35.3 

1992 4064 .334 20.8 15.5 19.9 17.4 35.4 

1993 4754 .360 21.0 15.5 20.1 17.5 35.7 

1994 5710 .404 20.8 15.3 19.7 17.2 35.7 

1995 5749 .380 20.5 15.0 19.5 17.0 35.7 

1996 5254 .400 20.8 15.1 19.9 17.2 36.6 

1997 6124 .424 20.6 14.8 19.5 17.0 36.9 

1998 6485 .449 20.9 14.9 19.8 17.1 36.8 

1999 6839 .449 20.5 14.6 19.2 16.7 37.0 

2000 7447 .449 20.8 14.7 19.4 16.9 37.1 

2001 7202 .461 20.6 14.6 19.1 16.7 37.4 

2002 7815 .485 20.6 14.4 19.1 16.7 38.0 

2003 7824 .496 20.9 14.6 19.3 16.9 38.7 

2004 8173 .520 20.8 14.3 19.2 16.7 39.4 

2005 7866 .495 21.4 14.6 19.8 17.2 40.2 

2006 6932 .461 21.9 15.0 20.2 17.6 40.8 

2007 7290 .490 22.1 15.1 20.4 17.7 42.0 

9 
Table 1 (continued) 

Fuel Economy Characteristics of 1975 to 2007 Light Duty Vehicles 

Cars and Trucks 

MODEL SALES <---- FUEL ECONOMY ----> TON 

YEAR (000) FRAC LAB ADJ ADJ ADJ 

55/45 CITY HWY COMP 

-MPG 

1975 10224 1.000 15.3 12.0 14.6 13.1 26.9 

1976 12334 1.000 16.7 13.2 15.7 14.2 29.3 

1977 14123 1.000 17.7 14.0 16.6 15.1 30.4 

1978 14448 1.000 18.6 14.7 17.5 15.8 29.9 

1979 13882 1.000 18.7 14.9 17.4 15.9 29.5 

1980 11306 1.000 22.5 17.6 21.5 19.2 31.2 

1981 10554 1.000 24.1 18.8 23.0 20.5 33.1 

1982 9732 1.000 24.7 19.2 23.9 21.1 34.1 

1983 10302 1.000 24.6 19.0 23.9 21.0 34.5 

1984 14020 1.000 24.6 19.1 24.0 21.0 34.7 

1985 14460 1.000 25.0 19.3 24.4 21.3 35.3 

1986 15365 1.000 25.7 19.8 25.0 21.8 35.7 

1987 14865 1.000 25.9 19.8 25.3 22.0 35.7 

1988 15295 1.000 25.9 19.6 25.2 21.9 36.2 

1989 14453 1.000 25.4 19.1 24.8 21.4 36.2 

1990 12615 1.000 25.2 18.7 24.6 21.2 36.5 

1991 12573 1.000 25.4 18.8 24.7 21.2 36.5 

1992 12172 1.000 24.9 18.2 24.4 20.8 36.8 

1993 13211 1.000 25.1 18.2 24.4 20.9 37.0 

1994 14125 1.000 24.6 17.8 23.8 20.4 37.0 

1995 15145 1.000 24.7 17.7 24.1 20.5 37.3 

1996 13144 1.000 24.8 17.6 24.0 20.4 37.6 

1997 14459 1.000 24.5 17.4 23.6 20.1 37.7 

1998 14458 1.000 24.5 17.2 23.6 20.1 37.9 

1999 15218 1.000 24.1 16.9 23.0 19.7 38.0 

2000 16574 1.000 24.3 16.9 23.0 19.8 37.9 

2001 15610 1.000 24.2 16.8 22.8 19.6 38.3 

2002 16119 1.000 24.1 16.6 22.5 19.4 38.7 

2003 15775 1.000 24.3 16.7 22.7 19.6 39.4 

2004 15711 1.000 24.0 16.3 22.4 19.3 39.9 

2005 15890 1.000 24.8 16.8 23.1 19.9 40.6 

2006 15041 1.000 25.3 17.1 23.5 20.2 41.2 

2007 14871 1.000 25.3 17.1 23.6 20.2 42.3 

10 
The distribution of fuel economy in any model year is of interest. In Figure 3, highlights 

of the distribution of car mpg are shown. Since 1975, half of the cars have consistently been 

within a few mpg of each other. The fuel economy difference between the least efficient and 

most efficient car increased from about 20 mpg in 1975 to nearly 50 mpg in 1986, but was less 

than 35 mpg in 1999. With the introduction for sale of the Honda Insight gasoline-electric 

hybrid vehicle in MY2000, the range once again approached 50 mpg. The increased market 

share of hybrid cars also accounts for the increase in the fuel economy of the best 1% of cars 

with the cutpoint for this strata now over 40 mpg. The ratio of the highest to lowest has 

increased from about three to one in 1975 to nearly five to one today, because the fuel economy 

of the least fuel efficient cars has remained roughly constant in comparison to the most fuel 

efficient cars whose fuel economy has more than doubled. 

The overall fuel economy distribution trend for trucks (see Figure 4) is narrower than that 

for cars, with a peak in the efficiency of the most efficient truck in the early 1980s when small 

pickup trucks equipped with diesel engines were being sold. As a result, the fuel economy range 

between the most efficient and least efficient truck peaked at about 25 mpg in 1982. The fuel 

economy range for trucks then narrowed, but with the introduction of the hybrid Escape SUV in 

MY2005, it is nearly 20 mpg. Like cars, half of the trucks built each year have always been 

within a few mpg of each year=s average fuel economy value. Appendix C contains additional 

fuel economy distribution data. 

Sales Weighted Car

Fuel Economy Distribution

Adjusted Composite MPG 

70 

60 

50 

Sales Weighted Truck

Fuel Economy Distribution

Adjusted Composite MPG 

70 

60 

50 

1975 1980 1985 1990 1995 2000 2005 

Model Year 

Best 

Car 

Worst 

Car 

50% of Cars 

First Hybrid 

Car 

Best 1% 

40 40 

30 30 

1975 1980 1985 1990 1995 2000 2005 

Model Year 

Best 

Truck 

Worst 

Truck 

50% of Trucks 

Best 1% 

20 20 Worst 1% 

Worst 1% 

10 10 

0 0 

Figure 3 

Figure 4 

11 
Table 2 

Vehicle Size and Design Characteristics of 1975 to 2007 

Cars 

<------ Vehicle Characteristics: -----------> <- Percent By: -> 

MODEL ADJ VOL WGHT ENG HP/ 0-60 TOP VEHICLE SIZE 

YEAR FRAC COMP CU-FT LB HP WT TIME SPD SMALL MID LARGE 

MPG 

1975 .806 13.5 4058 136 .0331 14.2 111 55.4 23.3 21.3 

1976 .788 14.9 4059 134 .0324 14.4 110 55.4 25.2 19.4 

1977 .800 15.6 110 3944 133 .0335 14.0 111 51.9 24.5 23.5 

1978 .773 16.9 109 3588 124 .0342 13.7 111 44.7 34.4 21.0 

1979 .778 17.2 109 3485 119 .0338 13.8 110 43.7 34.2 22.1 

1980 .835 20.0 104 3101 100 .0322 14.3 107 54.4 34.4 11.3 

1981 .827 21.4 106 3076 99 .0320 14.4 106 51.5 36.4 12.2 

1982 .803 22.2 106 3054 99 .0320 14.4 106 56.5 31.0 12.5 

1983 .777 22.1 109 3112 104 .0330 14.0 108 53.1 31.8 15.1 

1984 .761 22.4 108 3099 106 .0339 13.8 109 57.4 29.4 13.2 

1985 .746 23.0 108 3093 111 .0355 13.3 111 55.7 28.9 15.4 

1986 .717 23.7 107 3041 111 .0360 13.2 111 59.5 27.9 12.6 

1987 .722 23.8 107 3031 112 .0365 13.0 112 63.5 24.3 12.2 

1988 .702 24.1 107 3047 116 .0375 12.8 113 64.8 22.3 12.8 

1989 .693 23.7 108 3099 121 .0387 12.5 115 58.3 28.2 13.5 

1990 .698 23.3 107 3176 129 .0401 12.1 117 58.6 28.7 12.8 

1991 .678 23.4 107 3154 132 .0413 11.8 118 61.5 26.2 12.3 

1992 .666 23.1 108 3240 141 .0428 11.5 120 56.5 27.8 15.6 

1993 .640 23.5 108 3207 138 .0425 11.6 120 57.2 29.5 13.3 

1994 .596 23.3 108 3250 143 .0432 11.4 121 58.5 26.1 15.4 

1995 .620 23.4 109 3263 152 .0460 10.9 125 57.3 28.6 14.0 

1996 .600 23.3 109 3282 154 .0464 10.8 125 54.3 32.0 13.6 

1997 .576 23.4 109 3274 156 .0469 10.7 126 55.1 30.6 14.3 

1998 .551 23.4 109 3306 159 .0475 10.6 127 49.4 39.1 11.4 

1999 .551 23.0 109 3365 164 .0481 10.5 128 47.7 39.7 12.6 

2000 .551 22.9 110 3369 168 .0492 10.4 129 47.5 34.3 18.2 

2001 .539 23.0 109 3380 168 .0492 10.3 129 50.9 32.3 16.8 

2002 .515 23.1 109 3391 173 .0504 10.2 131 48.6 36.3 15.1 

2003 .504 23.2 109 3421 176 .0510 10.0 132 50.8 33.4 15.9 

2004 .480 23.1 110 3462 182 .0521 9.8 133 47.4 35.5 17.0 

2005 .505 23.5 111 3463 182 .0519 9.8 133 44.2 38.9 16.9 

2006 .539 23.3 112 3527 192 .0537 9.6 136 46.0 33.7 20.3 

2007 .510 23.4 111 3588 200 .0548 9.5 138 42.2 38.3 19.5 

12 
Table 2 (Continued) 

Vehicle Size and Design Characteristics of 1975 to 2007 

Trucks 

<-- Vehicle Characteristics: --------> <-- Percent By: --> 

MODEL SALES ADJ WGHT ENG HP/ 0-60 TOP VEHICLE TYPE 

YEAR FRAC COMP LB HP WT TIME SPD VAN SUV PICKUP 

MPG 

1975 .194 11.6 4072 142 .0349 13.6 114 23.0 9.4 67.6 

1976 .212 12.2 4155 141 .0340 13.8 113 19.2 9.3 71.4 

1977 .200 13.3 4135 147 .0356 13.3 115 18.2 10.0 71.8 

1978 .227 12.9 4151 146 .0351 13.4 114 19.1 11.6 69.3 

1979 .222 12.5 4252 138 .0325 14.3 111 15.6 13.0 71.5 

1980 .165 15.8 3869 121 .0313 14.5 108 13.0 9.9 77.1 

1981 .173 17.1 3806 119 .0311 14.6 108 13.5 7.5 79.1 

1982 .197 17.4 3806 120 .0317 14.5 109 16.2 8.5 75.3 

1983 .223 17.8 3763 118 .0313 14.5 108 16.6 12.6 70.8 

1984 .239 17.4 3782 118 .0310 14.7 108 20.2 18.7 61.1 

1985 .254 17.5 3795 124 .0326 14.1 110 23.3 20.0 56.6 

1986 .283 18.2 3738 123 .0330 14.0 110 24.0 17.8 58.2 

1987 .278 18.3 3713 131 .0351 13.3 113 26.9 21.1 51.9 

1988 .298 17.9 3841 141 .0366 12.9 115 24.8 21.2 53.9 

1989 .307 17.6 3921 146 .0372 12.8 116 28.8 20.9 50.3 

1990 .302 17.4 4005 151 .0377 12.6 117 33.2 18.6 48.2 

1991 .322 17.8 3948 150 .0379 12.6 117 25.5 27.0 47.4 

1992 .334 17.4 4056 155 .0382 12.5 118 30.0 24.7 45.3 

1993 .360 17.5 4073 162 .0398 12.1 120 30.3 27.6 42.1 

1994 .404 17.2 4125 166 .0403 12.0 121 24.8 28.4 46.7 

1995 .380 17.0 4184 168 .0401 12.0 121 28.9 31.6 39.5 

1996 .400 17.2 4225 179 .0423 11.5 124 26.8 36.0 37.2 

1997 .424 17.0 4344 187 .0429 11.4 126 20.7 40.0 39.3 

1998 .449 17.1 4283 187 .0435 11.2 126 23.0 39.8 37.2 

1999 .449 16.7 4412 197 .0446 11.0 128 21.4 41.4 37.2 

2000 .449 16.9 4375 197 .0448 11.0 128 22.7 42.2 35.1 

2001 .461 16.7 4463 209 .0466 10.6 131 17.1 47.9 35.0 

2002 .485 16.7 4546 219 .0482 10.4 134 15.9 53.6 30.5 

2003 .496 16.9 4586 221 .0481 10.4 134 15.7 52.6 31.6 

2004 .520 16.7 4710 236 .0501 10.0 137 11.7 57.7 30.7 

2005 .495 17.2 4668 237 .0505 10.0 137 18.8 51.9 29.2 

2006 .461 17.6 4628 234 .0504 10.0 137 16.6 52.9 30.6 

2007 .490 17.7 4723 247 .0521 9.7 140 13.1 59.0 27.9 

13 
Table 2 (Continued) 

Vehicle Size and Design Characteristics of 1975 to 2007 

Cars and Trucks 

<--- Vehicle Characteristics: --------> 

MODEL SALES ADJ WGHT ENG HP/ 0-60 TOP

YEAR FRAC COMP LB HP WT TIME SPD 

MPG 

1975 1.000 13.1 4060 137 .0335 14.1 112 

1976 1.000 14.2 4079 135 .0328 14.3 111 

1977 1.000 15.1 3982 136 .0339 13.8 112 

1978 1.000 15.8 3715 129 .0344 13.6 112 

1979 1.000 15.9 3655 124 .0335 13.9 110 

1980 1.000 19.2 3228 104 .0320 14.3 107 

1981 1.000 20.5 3202 102 .0318 14.4 107 

1982 1.000 21.1 3202 103 .0320 14.4 107 

1983 1.000 21.0 3257 107 .0327 14.1 108 

1984 1.000 21.0 3262 109 .0332 14.0 109 

1985 1.000 21.3 3271 114 .0347 13.5 110 

1986 1.000 21.8 3238 114 .0351 13.4 111 

1987 1.000 22.0 3221 118 .0361 13.1 112 

1988 1.000 21.9 3283 123 .0372 12.8 114 

1989 1.000 21.4 3351 129 .0382 12.5 115 

1990 1.000 21.2 3426 135 .0394 12.2 117 

1991 1.000 21.2 3410 138 .0402 12.1 118 

1992 1.000 20.8 3512 145 .0413 11.8 120 

1993 1.000 20.9 3519 147 .0416 11.8 120 

1994 1.000 20.4 3603 152 .0420 11.7 121 

1995 1.000 20.5 3613 158 .0438 11.3 123 

1996 1.000 20.4 3659 164 .0447 11.1 125 

1997 1.000 20.1 3727 169 .0452 11.0 126 

1998 1.000 20.1 3744 171 .0457 10.9 126 

1999 1.000 19.7 3835 179 .0465 10.7 128 

2000 1.000 19.8 3821 181 .0472 10.6 129 

2001 1.000 19.6 3879 187 .0480 10.5 130 

2002 1.000 19.4 3951 195 .0493 10.3 132 

2003 1.000 19.6 3999 199 .0496 10.2 133 

2004 1.000 19.3 4111 211 .0511 9.9 135 

2005 1.000 19.9 4060 209 .0512 9.9 135 

2006 1.000 20.2 4034 212 .0522 9.8 136 

2007 1.000 20.2 4144 223 .0534 9.6 139 

14 
Ton-MPG by Model Year 

(Three Year Moving Average) 

Ton-MPG 

20 

25 

30 

35 

40 

45 

50 

Cars 

Trucks 

1970 1975 1980 1985 1990 1995 2000 2005 2010 

Model Year 

Figure 5 

As shown in Table 2, the average weight of the overall fleet declined slightly in both 

MY2005 and MY2006, with a slight increase in car weight more than offset by a larger decrease 

in truck weight. Overall average horsepower and 0-60 acceleration time were basically 

unchanged in MY2005-2006. Average weight and performance are projected to increase in 

MY2007, and the projected levels would be the highest for the 1975-2007 timeframe. The 

projected 2007 weight has increased by over 900 pounds and the average horsepower level has 

more than doubled since the early 1980s. 

 The long term trends for both weight and performance have been steady increases. As 

shown in Figure 5, since 1975 Ton-MPG for both cars and trucks increased substantially; i.e. 

over 60% for cars and 80% for trucks. Typically, Ton-MPG for both vehicle types has increased 

at a rate of about one or two percent a year. 

Another dramatic trend over that time frame has been the substantial increase in 

performance of cars and light trucks as measured by their estimated 0-to-60 time. These trends 

are shown graphically in Figure 6 (for cars) and Figure 7 (for light trucks) which are plots of fuel 

economy versus performance, with model years as indicated. Both graphs show the same story: 

in the late 1970s and early 1980s, responding to the regulatory requirements for mpg 

improvement, the industry increased mpg and kept performance roughly constant. After the 

regulatory mpg requirements stabilized, mpg improvements slowed and performance 

dramatically improved. This trend toward increased performance is as important as the truck 

market share trend in understanding trends in overall fleet mpg. Figures 8 and 9 are similar to 

Figures 6 and 7, but show the trends in weight and laboratory fuel economy and show that the 

era of weight reductions that took place for both cars and trucks between 1975 and the early 

1980s has been followed by an era of weight increases until 2005. 

15 
Car 55/45 Laboratory MPG vs 0 to 60 Time

 by Model Year 

55/45 Lab. MPG 

9 10 11 12 13 14 15 

0 to 60 Time (Sec.) 

Figure 6 

Truck 55/45 Laboratory MPG vs 0 to 60 Time

 by Model Year 

55/45 Lab. MPG 

9 10 11 12 13 14 15 

0 to 60 Time (Sec.) 

Figure 7 

15 

20 

25 

30 

2000 2007 

1975 

1985 1980 

1989 

1995 

10 

15 

20 

25 

2000 2007 1995 

1990 

1975 1979 

1980 

1985 1987 

16 
Car 55/45 Laboratory MPG vs Inertia Weight

 by Model Year 

55/45 Lab. MPG 

2500 3000 3500 4000 4500

Inertia Weight

Figure 8

Truck 55/45 Laboratory MPG vs Inertia Weight

 by Model Year 

15 

20 

25 

30 

2000 1985 

1988 2007 

1980 

1979 

1977 

1975 

10 

15 

20 

25 

55/45 Lab. MPG 

2000 

1985 

1987 

2007 

1995 1990 

1975 

1980 

3500 4000 4500 5000

Inertia Weight

Figure 9

17 
IV. Trends by Vehicle Type, Size, and Weight 

Table 1 showed that for the past several years trucks have accounted for about 50 percent 

of the light-duty vehicles produced each year. MY2004 was the peak year for trucks with 52 

percent market share, and trucks have been between 46 and 50 percent since. Considering the 

five classes: cars, wagons, sports utility vehicles (SUVs), vans, and pickups, since 1975 the 

biggest overall increase in market share has been for SUVs, up from less than two percent in 1975 

to 29 percent this year (see Figure 10 and Table 3). The biggest overall decrease has been for 

cars, down from over 70 percent of the fleet in 1975 to about 50 percent. By comparison the sales 

fraction for pickup trucks has remained constant at about 15 percent of the market. 

Figures 11 to 15 compare sales fractions by vehicle type and size with the fleet again 

stratified into five vehicle types: cars (i.e., coupes, sedans, and hatchbacks), station wagons, vans, 

SUVs, and pickup trucks; and three vehicle sizes: small, midsize, and large. As shown in Figure 

15, large cars accounted for about 20 percent of all car sales in the late 1970s, but their share of 

the car market dropped in the early 1980s to about 12 percent of the market where it remained for 

about two decades, but has since increased. Within the car segment, the market share for small 

cars peaked in the late 1980s at about 65 percent and is now lower than at anytime since 1975. 

Sales Fraction by Vehicle Type 

(Three Year Moving Average) 

Sales Fraction 100%

1976 1980 1984 1988 1992 1996 2000 2004 

Model Year 

SUV 

80% 

60% 

Car 

40% 

Wagon 

20% Van 

Pickup 

0% 

Figure 10 

18 
Large wagons accounted for more than 20 percent of the wagon segment of the market in 

the late 1970s but then lost market share relatively consistently and were not produced at all 

between 1996 and 2004 when they reemerged. They now account for about 15 percent of all 

wagons, but less than one percent of all light vehicles. Similarly (see Figure 13), large vehicles 

accounted for nearly 40 percent of all vans through the early 1980s compared to less than 10 

percent the past five years. Small vans have never had a significant market share, and none have 

been produced in recent years. Figures 14 and 15 show that there have been an overall and 

significant trend towards increased market share for both large SUVs and pickups, but there has 

been a recent decrease in large SUV sales fraction. 

Table 3 compares the sales fractions by vehicle type and size on a different basis, that for 

the total market. Since 1975, the largest increases in sales fractions have been for midsize and 

large SUVs. These two classes are expected to account for over 25 percent of all light vehicles 

built this year, compared to combined totals of about 1.3 and 4.5 percent in 1975 and 1988, 

respectively. Conversely, the largest sales fraction decrease has occurred for small cars which 

accounted for 40 percent of all light-duty vehicles produced in 1975 and over 43 percent in 1988, 

but less than 20 percent this year. For MY2007, it is projected that the market share for midsize 

cars will exceed that for small cars. An overall decrease has occurred for large cars which 

accounted for about 15 percent of total light-duty sales in 1975 when they ranked third. Between 

then and 1988, their sales fraction dropped to less than 10 percent of the total market. 

Car Sales Fraction by Vehicle Size Wagon Sales Fraction by Vehicle Size

(Three Year Moving Average) (Three Year Moving Average)

Sales Fraction Sales Fraction 

Small

Midsize

Large

1976 1980 1984 1988 1992 1996 2000 2004 1976 1980 1984 1988 1992 1996 2000 2004 

Model Year Model Year

Figure 11 Figure 12

0% 

20% 

40% 

60% 

80% 

100% 

Large 

Midsize 

Small 

0% 

20% 

40% 

60% 

80% 

100% 

19 
Van Sales Fraction by Vehicle Size 

(Three Year Moving Average) 

Sales Fraction 100% 

80% 

60% 

40% 

20% 

0% 

 Large

 Midsize

 Small 

SUV Sales Fraction by Vehicle Size 

(Three Year Moving Average) 

Sales Fraction 100% 

80% 

60% 

40% 

20% 

0% 

 Large

 Midsize

 Small 

1976 1980 1984 1988 1992 1996 2000 2004 1976 1980 1984 1988 1992 1996 2000 2004 

Model Year Model Year 

Figure 13 Figure 14 

Pickup Sales Fraction by Vehicle Size 

(Three Year Moving Average) 

Sales Fraction 100% 

80% 

60% 

40% 

20% 

0% 

1976 1980 1984 1988 1992 1996 2000 2004 

 Large

 Midsize

 Small 

Model Year 

Figure 15 

20 
Table 3 

Sales Fractions of MY1975, MY1988 and MY2007

Light-Duty Vehicles by Vehicle Size and Type 

Differences in Sales Fraction 

Vehicle Sales Fraction From 1975 From 1975 From 1988 

Type Size 1975 1988 2007 To 2007 To 1988 To 2007 

Car Small 40.0% 43.8% 17.2% -22.8% 3.9% -26.6% 

Midsize 16.0% 13.8% 18.5% 2.5% -2.1% 4.7% 

Large 15.2% 8.5% 9.3% -5.9% -6.7% .8% 

All 71.1% 66.2% 45.1% -26.1% -5.0% -21.1% 

Wagon Small 4.7% 1.7% 4.3% -0.4% -3.0% 2.6% 

Midsize 2.8% 1.9% 1.0% -1.8% -1.0% -0.8% 

Large 1.9% .5% .6% -1.3% -1.4% .1% 

All 9.4% 4.0% 5.9% -3.5% -5.4% 1.9% 

Van Small .0% .4% .0% .0% .3% -0.4% 

Midsize 3.0% 6.2% 6.2% 3.3% 3.2% .1% 

Large 1.5% .9% .2% -1.3% -0.6% -0.7% 

All 4.5% 7.4% 6.4% 2.0% 2.9% -1.0% 

SUV Small .5% 1.9% 1.2% .7% 1.4% -0.7% 

Midsize 1.2% 4.0% 14.8% 13.6% 2.8% 10.8% 

Large .1% .5% 13.0% 12.9% .3% 12.5% 

All 1.8% 6.3% 28.9% 27.1% 4.5% 22.6% 

Pickup Small 1.6% 2.2% .0% -1.6% .7% -2.2% 

Midsize .5% 6.9% 1.9% 1.3% 6.3% -5.0% 

Large 11.0% 7.0% 11.8% .8% -4.1% 4.8% 

All 13.1% 16.1% 13.7% .5% 2.9% -2.4% 

All Trucks 19.4% 29.8% 49.0% 29.6% 10.4% 19.2% 

21 
Figures 16 through 20 show trends in performance, weight, and adjusted fuel economy for 

cars, wagons, vans, SUVs, and pickups. For all five vehicle types, there has been a clear long 

term trend towards increased weight, moderating since 2005 for wagons, vans, and SUVs. 

 Table 4 shows the lowest, average, and highest adjusted mpg performance by vehicle class and 

size for three selected years. For both 1988 and 2007, the mpg performance is such that the 

midsize vehicles in all classes have better fuel economy than the corresponding entry for small 

vehicles in 1975. In Table 5, the percentage changes obtainable from the entries in Table 4 are 

presented. Average mpg for four classes (midsize cars, large cars, midsize wagons and midsize 

SUVs) have improved over 80 percent since 1975. The average fuel economy improvements 

between 1975 and 2007 for the truck classes range from 5 percent for midsize pickups to 91 

percent for midsize SUVs. Since 1988, average fuel economy has decreased for small cars, all 

wagons, small SUVs, and midsize pickups and the largest improvements in average mpg has been 

18 and 20 percent for midsize and large SUVs, respectively. 

Fuel Economy and Performance Fuel Economy and Performance

(Three Year Moving Average) (Three Year Moving Average)

Cars Wagons

MPG, 0 to 60 (sec.) Inertia Weight (lbs.) MPG, 0 to 60 (sec.) Inertia Weight (lbs.) 

Weight 

Adjusted Composite MPG 

0 to 60 Time 

35 5000 35 5000

30 4500 30 4500

25 4000 25 4000 

20 3500 20 3500 

15 3000 15 3000

10 2500 10 2500 

5 2000 5 2000

1975 1980 1985 1990 1995 2000 2005 1975 1980 1985 1990 1995 2000 2005

Model Year Model Year 

 Figure 16 Figure 17 

Weight 

Adjusted Composite MPG 

0 to 60 Time 

22 
Fuel Economy and Performance 

(Three Year Moving Average) 

Vans 

35 

MPG, 0 to 60 (sec.) Inertia Weight (lbs.) 5000 

30 4500 

25 4000 

20 3500 

15 3000 

10 2500 

5 2000 

1975 1980 1985 1990 1995 2000 2005 

Model Year 

Weight 

Adjusted Composite MPG 

0 to 60 Time 

Fuel Economy and Performance 

(Three Year Moving Average) 

SUVs 

35 

MPG, 0 to 60 (sec.) Inertia Weight (lbs.) 5000 

30 4500 

25 4000 

20 3500 

15 3000 

10 2500 

5 2000 

1975 1980 1985 1990 1995 2000 2005 

Model Year 

Weight 

Adjusted Composite MPG 

0 to 60 Time 

Figure 18 Figure 19 

Fuel Economy and Performance 

(Three Year Moving Average) 

Pickups 

MPG, 0 to 60 (sec.) Inertia Weight (lbs.) 35 5000 

30 4500 

25 4000 

20 3500 

15 3000 

10 2500 

5 2000 

1975 1980 1985 1990 1995 2000 2005 

Model Year 

Figure 20 

Weight 

Adjusted Composite MPG 

0 to 60 Time 

23 
24 

Table 4 

 Lowest, Average and Highest Adjusted Fuel Economy 

 by Vehicle Type and Size 

Vehicle 1975 1988 2007 

Type Size Low Avg. High Low Avg. High Low Avg. High 

Car Small 8.6 15.6 28.3 7.5 25.7 54.4 10.4 24.0 42.9 

 Midsize 8.6 11.6 18.4 10.5 22.6 27.7 12.0 24.5 46.2 

 Large 8.4 11.2 14.6 10.0 20.6 26.0 11.8 20.5 26.0 

 All 8.4 13.4 28.3 7.5 24.2 54.4 10.4 23.4 46.2 

Wagon Small 11.8 19.1 24.1 17.1 26.3 33.2 16.2 25.9 31.3 

 Midsize 8.4 11.3 25.0 17.5 22.2 27.7 15.0 21.4 28.3 

 Large 8.4 10.2 12.8 19.2 19.4 19.4 12.7 18.1 22.4 

 All 8.4 13.8 25.0 17.1 23.3 33.2 12.7 24.0 31.3 

Van Small 16.2 17.5 18.5 15.5 20.6 25.0 

 Midsize 8.2 11.3 18.4 11.3 18.4 23.4 17.9 19.9 23.0 

 Large 8.9 10.7 14.5 9.9 14.3 16.8 14.4 15.8 17.0 

 All 8.2 11.1 18.5 9.9 17.9 25.0 14.4 19.8 23.0 

SUV Small 10.2 13.7 16.3 15.6 20.4 27.7 16.1 17.9 22.8 

 Midsize 8.2 10.2 18.4 10.2 16.5 23.6 12.7 19.5 29.7 

 Large 7.9 10.3 13.7 12.2 14.0 18.8 12.2 16.8 21.7 

 All 7.9 11.0 18.4 10.2 17.2 27.7 12.2 18.1 29.7 

Pickup Small 13.0 19.2 20.8 13.3 21.0 24.6 

 Midsize 17.8 17.9 18.0 15.3 21.3 25.9 15.4 18.8 23.7 

 Large 7.6 11.1 18.5 9.8 15.2 21.0 12.2 15.8 21.2 

 All 7.6 11.9 20.8 9.8 18.1 25.9 12.2 16.2 23.7 

All Cars 8.4 13.5 28.3 7.5 24.1 54.4 10.4 23.4 46.2 

All Trucks 7.6 11.6 20.8 9.8 17.9 27.7 12.2 17.7 29.7 

All Vehicles 7.6 13.1 28.3 7.5 21.9 54.4 10.4 20.2 46.2 
Table 5 

Percent Change in Lowest, Average and Highest Adjusted Fuel Economy

by Vehicle Type and Size 

Vehicle From 1975 to 2007 From 1975 to 1988 From 1988 to 2007 

Type Size Low Avg High Low Avg. High Low Avg. High 

Car Small 21% 54% 52% -12% 65% 92% 39% -6% -20% 

Midsize 40% 111% 151% 22% 95% 51% 14% 8% 67% 

Large 40% 83% 78% 19% 84% 78% 18% 0% 0% 

All 24% 75% 63% -10% 81% 92% 39% -2% -14% 

Wagon Small 37% 36% 30% 45% 38% 38% -4% -1% -5% 

Midsize 79% 89% 13% 108% 96% 11% -13% -3% 2% 

Large 51% 77% 75% 129% 90% 52% -33% -6% 15% 

All 51% 74% 25% 104% 69% 33% -25% 3% -5% 

Van Small -3% 18% 35% 

Midsize 118% 76% 25% 38% 63% 27% 58% 8% -1% 

Large 62% 48% 17% 11% 34% 16% 45% 10% 1% 

All 76% 78% 24% 21% 61% 35% 45% 11% -7% 

SUV Small 58% 31% 40% 53% 49% 70% 3% -11% -17% 

Midsize 55% 91% 61% 24% 62% 28% 25% 18% 26% 

Large 54% 63% 58% 54% 36% 37% 0% 20% 15% 

All 54% 65% 61% 29% 56% 51% 20% 5% 7% 

Pickup Small 2% 9% 18% 

Midsize -12% 5% 32% -13% 19% 44% 1% -11% -7% 

Large 61% 42% 15% 29% 37% 14% 24% 4% 1% 

All 61% 36% 14% 29% 52% 25% 24% -9% -7% 

All Cars 24% 73% 63% -10% 79% 92% 39% -2% -14% 

All Trucks 61% 53% 43% 29% 54% 33% 24% 0% 7% 

All Vehicles 37% 54% 63% 0% 67% 92% 39% -7% -14% 

25 
Cars and light trucks with conventional drivetrains have a fuel consumption and weight 

relationship which is well known and is shown on Figures 21 and 22. Fuel consumption 

increases linearly with weight. Because vehicles with different propulsion systems, i.e., diesels 

and hybrids, occupy a different place on such a fuel consumption and weight plot, the data for 

hybrid and diesel vehicles are plotted separately and excluded from the regression lines shown 

on the graphs. At constant weight, MY2007 cars consume about 30 to 40 percent less fuel per 

mile than their MY1975 counterparts 

On this same constant weight basis, this year=s cars with diesel engines nominally 

consume about 30 percent less fuel than the conventionally powered ones, while this year=s 

hybrid cars are about 50 percent better. Similarly, at constant weight this year=s conventionally 

powered trucks achieve about 40 percent better fuel consumption than MY1975 vehicles did. 

Figures 23 and 24 show that the relationship between interior volume and fuel 

consumption is currently not as important as it used to be. The data points on both of these 

graphs exclude two seaters and represent sales weighted average fuel consumption calculated at 

increments of 1.0 cu. ft. As was done for Figures 21 and 22, the data points for hybrid and diesel 

vehicles were plotted separately from that for the conventionally powered vehicles. 

Figures 25 and 26 show the improvement that occurred between 1975 and 2007 for fuel 

consumption as a function of 0-to-60 time for cars and trucks. Figures 27 and 28 compare TonMPG data versus 0-to-60 time and show that at constant vehicle performance, there has been 

substantial improvement in Ton-mpg, particularly for hybrid and diesel vehicles. 

26 
Laboratory 55/45 Fuel Consumption

 vs Inertia Weight

 MY1975 and MY2007 Cars

0 

2 

4 

6 

8 

10 

12 

Gal / 100 miles 

2007 

Hybrids 

Diesels 

1975 

1975 

2007 

1500 2500 3500 4500 5500 6500 7500 

Inertia Weight 

Figure 21 

Laboratory 55/45 Fuel Consumption

 vs Inertia Weight

 MY1975 and MY2007 Trucks

0 

2 

4 

6 

8 

10 

12 

Gal / 100 miles 

1975 

2007 

Diesels 

Hybrids 

1975 

2007 

1500 2500 3500 4500 5500 6500 7500 

Inertia Weight 

Figure 22 

27 
0 

2 

4 

6 

8 

10 

12 

Hybrids 

Diesels 

Conventional 

Laboratory 55/45 Fuel Consumption

 vs Interior Volume

 MY1978 Cars 

12 

Gal / 100 miles 

10 

8 

6 

4 

2 Diesels 

Conventional 

0 

60 80 100 120 140 160 180 

Interior Volume 

Figure 23 

Laboratory 55/45 Fuel Consumption

 vs Interior Volume

 MY2007 Cars

Gal / 100 miles 

60 80 100 120 140 160 180 

Interior Volume 

Figure 24 

28 
Table 6 

Adjusted Fuel Consumption (Gal./100 miles) by Vehicle Type and Size 

Vehicle 1975 1988 2007 

Type Size Low Avg. High Low Avg. High Low Avg. High 

Car Small 11.6 6.4 3.5 13.3 3.9 1.8 9.6 4.2 2.3 

Midsize 11.6 8.6 5.4 9.5 4.4 3.6 8.3 4.1 2.2 

Large 11.9 8.9 6.8 10.0 4.9 3.8 8.5 4.9 3.8 

All 11.9 7.5 3.5 13.3 4.1 1.8 9.6 4.3 2.2 

Wagon Small 8.5 5.2 4.1 5.8 3.8 3.0 6.2 3.9 3.2 

Midsize 11.9 8.8 4.0 5.7 4.5 3.6 6.7 4.7 3.5 

Large 11.9 9.8 7.8 5.2 5.2 5.2 7.9 5.5 4.5 

All 11.9 7.2 4.0 5.8 4.3 3.0 7.9 4.2 3.2 

Van Small 6.2 5.7 5.4 6.5 4.9 4.0 

Midsize 12.2 8.8 5.4 8.8 5.4 4.3 5.6 5.0 4.3 

Large 11.2 9.3 6.9 10.1 7.0 6.0 6.9 6.3 5.9 

All 12.2 9.0 5.4 10.1 5.6 4.0 6.9 5.1 4.3 

SUV Small 9.8 7.3 6.1 6.4 4.9 3.6 6.2 5.6 4.4 

Midsize 12.2 9.8 5.4 9.8 6.1 4.2 7.9 5.1 3.4 

Large 12.7 9.7 7.3 8.2 7.1 5.3 8.2 6.0 4.6 

All 12.7 9.1 5.4 9.8 5.8 3.6 8.2 5.5 3.4 

Pickup Small 7.7 5.2 4.8 7.5 4.8 4.1 

Midsize 5.6 5.6 5.6 6.5 4.7 3.9 6.5 5.3 4.2 

Large 13.2 9.0 5.4 10.2 6.6 4.8 8.2 6.3 4.7 

All 13.2 8.4 4.8 10.2 5.5 3.9 8.2 6.2 4.2 

All Cars 11.9 7.5 3.5 13.3 4.1 1.8 9.6 4.3 2.2 

All Trucks 13.2 8.6 4.8 10.2 5.6 3.6 8.2 5.6 3.4 

All Vehicles 13.2 7.6 3.5 13.3 4.6 1.8 9.6 5.0 2.2 

29 
Table 7 

Percent Change* in Adjusted Fuel Consumption by Vehicle Type and Size 

Vehicle From 1975 to 2007 From 1975 to 1988 From 1988 to 2007 

Type Size Low Avg. High Low Avg. High. Low Avg. High 

Car Small 17% 34% 34% -15% 39% 49% 28% -8% -28% 

Midsize 28% 52% 59% 18% 49% 33% 13% 7% 38% 

Large 29% 45% 44% 16% 45% 44% 15% 0% 0% 

All 19% 43% 37% -12% 45% 49% 28% -5% -22% 

Wagon Small 27% 25% 22% 32% 27% 27% -7% -3% -7% 

Midsize 44% 47% 13% 52% 49% 10% -18% -4% 3% 

Large 34% 44% 42% 56% 47% 33% -52% -6% 13% 

All 34% 42% 20% 51% 40% 25% -36% 2% -7% 

Van Small -- -- -- -5% 14% 26% -- -- --

Midsize 54% 43% 20% 28% 39% 20% 36% 7% 0% 

Large 38% 32% 14% 10% 25% 13% 32% 10% 2% 

All 43% 43% 20% 17% 38% 26% 32% 9% -8% 

SUV Small 37% 23% 28% 35% 33% 41% 3% -14% -22% 

Midsize 35% 48% 37% 20% 38% 22% 19% 16% 19% 

Large 35% 38% 37% 35% 27% 27% 0% 15% 13% 

All 35% 40% 37% 23% 36% 33% 16% 5% 6% 

Pickup Small -- -- -- 3% 8% 15% -- -- --

Midsize -16% 5% 25% -16% 16% 30% 0% -13% -8% 

Large 38% 30% 13% 23% 27% 11% 20% 5% 2% 

All 38% 26% 13% 23% 35% 19% 20% -13% -8% 

All Cars 19% 42% 37% -12% 45% 49% 28% -5% -22% 

All Trucks 38% 35% 29% 23% 35% 25% 20% 0% 6% 

All Vehicles 27% 34% 37% -1% 39% 49% 28% -9% -22% 

*Note: A Negative Change indicates that the fuel consumption has increased. 

30 
4 

Laboratory 55/45 Fuel Consumption

 vs 0 to 60 Time

 MY1975 and MY2007 Cars

Gal / 100 miles 

12 

1975 

10 2007 

1975 Hybrids 

8 Diesels 

6 

4 

2007 

2 

0 

4 6 8 10 12 14 16 18 20 22 24 

0 to 60 Time (Sec.) 

Figure 25 

Laboratory 55/45 Fuel Consumption

 vs 0 to 60 Time

 MY1975 and MY2007 Trucks

12 

10 

8 

6 

4 

2 

0 

Gal / 100 miles 

1975 

2007 

6 8 

1975 

2007 

Hybrids 

Diesels 

10 12 14 16 18 20 22 24 

0 to 60 Time (Sec.) 

Figure 26 

31 
1975 

2007 

Hybrids 

Diesels 

Power 

2007 

1975 

MY1975 and MY2007 Cars 

Ton-MPG 

100 

80 

60 

40 

20 

0 

0 5 10 15 20 25 

Figure 27 0 to 60 Time (Sec.) 

Ton-MPG vs 0 to 60 Time

 MY1975 and MY2007 Trucks

Ton-MPG 100 

1975

2007

80 Hybrids

Diesels

60 

2007 

40

20

1975 

0 

0 5 10 15 20 25 

0 to 60 Time (Sec.) 

Figure 28 

32 
Figure 29 and Table 8 show some of the changes in the distribution of inertia weight that 

have occurred over the years for the light-duty fleet. In 1975, 13 percent of all light-duty 

vehicles had inertia weights of less than 3000 lb compared to two percent in 2007. Since 1988, 

market share for vehicles with weight of 5000 pounds or more has increased from three percent 

to 21 percent. 

25% 

30% 

Sales Fraction 

Distribution of Light Vehicle Inertia Weight For Three Model Years 

1975 1988 2007 

20% 

15% 

10% 

5% 

0% 

1750 2000 2250 2500 2750 3000 3500 4000 4500 5000 5500 6000 

Inertia Weight 

Figure 29 

Table 8 

Light Vehicle Sales Fraction

by Inertia Weight Class

for Three Model Years 

Inertia <---- Model Year ----> 

Weight 1975 1988 2007 

<3000 13.4% 27.2% 2.1% 

3000 8.7% 25.4% 12.3% 

3500 10.6% 25.2% 20.6% 

4000 20.6% 13.2% 25.8% 

4500 21.3% 6.0% 18.0% 

5000 16.7% 2.4% 8.9% 

5500 8.7% .5% 5.6% 

>5500 .0% .0% 6.8% 

Avg Wt. 4060 3283 4144 

33 
Figures 30 through 34 provide an indication of the market share of different weight vehicles 

within the different classes. Trends within classes are shown which underlie the increasing 

weight shown by the fleet as a whole. In 1975, about 40 percent of the cars had an inertia weight 

of 4500 lb or more compared to about 5 percent this year. For MY2007, three weight classes 

(3000, 3500 and 4000 lbs) account for nearly 90 percent of all cars. Conversely, the market 

share of trucks in the inertia weight classes of 4500 lb or more have increased substantially, and 

these vehicles currently account for over 70 percent of all trucks, compared to about 30 percent 

in 1975. Figures 32, 33, and 34 provide additional details of the truck data presented in Figure 

31 for vans, SUVs, and pickups respectively. Appendixes D, E, and F contain a series of tables 

describing light-duty vehicles at the vehicle size/type level of stratification in more detail; 

Appendix G provides similar data by vehicle type and inertia weight class. 

Car Market Share by Inertia Weight Class Truck Market Share by Inertia Weight Class 

(Three Year Moving Average) (Three Year Moving Average) 

100% 

Market Share (%) 100% 

Market Share (%) 

75% 75% 

50% 50% 

25% 25% 

0% 0% 

1976 1980 1984 1988 1992 1996 2000 2004 

Model Year 

Figure 30 Figure 31 

<2750 

3500 

4000 

3000 

2750 

1976 1980 1984 1988 1992 1996 2000 2004 

Model Year 

3500 

<3500 

4000 

4500 

>4500 

34 
Van Market Share by Inertia Weight Class SUV Market Share by Inertia Weight Class 

(Three Year Moving Average) (Three Year Moving Average) 

Market Share (%) Market Share (%) 

5000

<4500 

Model Year Model Year

Figure 32 Figure 33

Pickup Market Share by Inertia Weight Class

(Three Year Moving Average)

Market Share (%) 

1976 1980 1984 1988 1992 1996 2000 2004

Model Year

Figure 34

1976 1980 1984 1988 1992 1996 2000 2004 

0% 

5% 

10% 

15% 

20% 

25% 

30% 

<3500 

3500 

>4000 

4000 

1976 1980 1984 1988 1992 1996 2000 2004 

0% 

5% 

10% 

15% 

20% 

25% 

30% 

0% 

5% 

10% 

15% 

20% 

25% 

30% 

<3500 

4000 

>4500 

3500 

4500 

35 
V. Technology Trends 

Table 9 repeats the sales fraction and adjusted composite fuel economy data from Tables 

1 and 2 and adds three measures of powertrain information: engine displacement (CID), 

horsepower (HP), and specific power (HP/CID). This table also includes sales fraction data 

giving the percent of vehicles that: have front- (FWD) or four-wheel drive (4wd); have manual, 

lockup, or continuously variable (CVT) transmissions; have port or throttle body fuel injection 

(TBI) or are Diesels; are equipped with engines that have more than two valves per cylinder; use 

variable valve timing (VVT); and use hybrid vehicle technology. 

For the overall MY2007 fleet, FWD continues to account for about one-half of the 

market and 4wd for about 30 percent. With transmissions, manuals remain less than 10 percent 

of the market, while CVTs have grown to seven percent. Over 70 percent of the MY2007 fleet 

have multi-valve engines, and nearly 60 percent use VVT, an all-time high. Hybrids are over 

two percent of the fleet for the first time, while diesels represent just 0.1 percent of the MY2007 

sales. Appendix K contains additional data on fuel metering and number of valves per cylinder. 

Table 10 compares technology usage for MY2007 by vehicle type and size. As discussed 

earlier, wheelbase is used in this report to distinguish whether a truck is small, mid-size, or large, 

and four EPA car classes (Two-Seater, Minicompact, Compact, and Subcompact) have been 

combined to form the small car class. For this table, the car classes are separated into cars and 

station wagons, so that the table stratifies light-duty vehicles into a total of 15 vehicle types and 

sizes. Note that this table does not contain any data for small vans and small pickups, because 

none have been produced for several years. 

Front-wheel drive (FWD) is used heavily in all of the car classes, in small wagons and in 

midsize vans. By comparison, none of this year=s pickups or large vans will have front-wheel 

drive, and it is used less often in SUVs or large vans than in midsize wagons. Conversely, fourwheel drive (4WD) is used heavily in SUVs and pickups. A large portion of the midsize and 

large wagons also have 4WD, but very little use of it is made in vans and cars. 

Manual transmissions are used primarily in small vehicles and midsize pickups. 

Similarly, usage of engines with more than two valves per cylinder is more prevalent on small 

and midsize vehicles than on larger ones. 

Detailed tabulations of different technology types, including technology usage 

percentages for other model years, can be found in the Appendixes. 

36 
Table 9 

Powertrain Characteristics of 1975 to 2007 Cars (Percentage Basis) 

MODEL SALES ADJ ENGINE HP/ DRIVETRAIN TRANSMISSION FUEL METERING MultiYEAR FRAC COMP CID HP CID Front 4wd Manual Lock CVT Port TBI Dsl Valve VVT Hybrid

MPG 

1975 .806 13.5 288 136 .515 6.5 19.9 5.1 .2 

1976 .788 14.9 287 134 .502 5.8 17.1 3.2 .3 

1977 .800 15.6 279 133 .516 6.8 16.8 4.2 .5 

1978 .773 16.9 251 124 .538 9.6 20.2 6.7 5.1 .9 

1979 .778 17.2 238 119 .545 11.9 .3 22.3 8.0 4.7 2.1 

1980 .835 20.0 188 100 .583 29.7 .9 31.9 16.5 6.2 .7 4.4 

1981 .827 21.4 182 99 .594 37.0 .7 30.4 33.3 6.1 2.6 5.9 

1982 .803 22.2 175 99 .609 45.6 .8 29.7 51.4 7.2 9.8 4.7 

1983 .777 22.1 182 104 .615 47.3 3.1 26.5 56.7 9.5 18.9 2.1 

1984 .761 22.4 179 106 .637 53.7 1.0 24.1 58.3 15.0 24.4 1.7 

1985 .746 23.0 177 111 .671 61.6 2.1 22.8 58.7 21.4 32.0 .9 

1986 .717 23.7 167 111 .701 71.1 1.1 24.8 58.0 36.7 28.4 .3 

1987 .722 23.8 162 112 .732 77.0 1.1 24.9 59.5 42.5 30.5 .3 

1988 .702 24.1 160 116 .759 81.7 .8 24.3 66.1 53.7 30.0 

1989 .693 23.7 163 121 .783 82.5 1.0 21.0 69.3 .1 62.4 27.8 .0 

1990 .698 23.3 163 129 .829 84.6 1.0 19.6 72.9 .0 77.5 21.1 .0 .6 

1991 .678 23.4 163 132 .851 83.2 1.4 20.5 73.5 .0 78.0 21.8 .1 2.4 

1992 .666 23.1 170 141 .868 80.8 1.1 17.4 76.4 89.5 10.4 .1 4.6 

1993 .640 23.5 166 138 .865 85.1 1.2 17.8 77.0 91.6 8.4 4.8 

1994 .596 23.3 168 143 .884 84.4 .4 16.7 79.3 94.9 5.1 8.0 

1995 .620 23.4 167 152 .945 82.0 1.2 16.3 81.9 98.8 1.2 .1 9.8 

1996 .600 23.3 165 154 .958 86.5 1.5 14.8 83.6 .0 98.8 1.1 .1 11.7 

1997 .576 23.4 164 156 .974 86.5 1.7 13.5 85.8 .1 99.1 .8 .1 58.6 11.3 

1998 .551 23.4 164 159 .993 87.0 2.3 12.3 87.3 .1 99.7 .1 .2 61.4 18.4 

1999 .551 23.0 166 164 1.009 87.2 2.2 10.9 88.4 .0 99.7 .1 .2 64.6 17.1 

2000 .551 22.9 165 168 1.032 84.9 2.1 11.2 87.7 .0 99.7 .1 .2 65.1 23.4 .1 

2001 .539 23.0 165 168 1.042 84.1 3.2 11.4 87.5 .2 99.7 .3 67.2 28.3 .0 

2002 .515 23.1 166 173 1.066 84.9 3.8 11.2 88.1 .4 99.6 .4 69.9 33.9 .3 

2003 .504 23.2 166 176 1.086 81.7 3.8 11.1 87.9 .9 99.6 .4 73.5 41.2 .6 

2004 .480 23.1 168 182 1.106 80.8 5.4 10.2 88.2 1.4 99.7 .3 77.2 44.2 .9 

2005 .505 23.5 166 182 1.116 79.7 5.8 9.3 88.0 2.6 99.6 .4 78.2 51.7 2.1 

2006 .539 23.3 171 192 1.142 76.8 5.7 9.8 87.5 2.4 99.4 .6 80.5 61.1 1.5 

2007 .510 23.4 176 200 1.157 75.4 7.6 11.5 77.0 10.3 99.9 .1 82.1 67.9 3.0 

37 
Table 9 (continued) 

Powertrain Characteristics of 1975 to 2007 Trucks (Percentage Basis) 

MODEL SALES ADJ ENGINE HP/ DRIVETRAIN TRANSMISSION FUEL METERING MultiYEAR FRAC COMP CID HP CID Front 4wd Manual Lock CVT Port TBI Dsl Valve VVT Hybrid

MPG 

1975 .194 11.6 311 142 .476 17.1 37.0 .1 

1976 .212 12.2 319 141 .458 22.9 34.8 .1 

1977 .200 13.3 318 147 .482 23.6 32.0 .1 

1978 .227 12.9 314 146 .481 29.0 32.4 .1 .8 

1979 .222 12.5 298 138 .486 18.0 35.2 2.1 .3 1.8 

1980 .165 15.8 248 121 .528 1.4 25.0 53.0 24.6 1.7 3.5 

1981 .173 17.1 247 119 .508 1.9 20.1 51.6 31.1 1.1 5.6 

1982 .197 17.4 243 120 .524 1.7 20.0 45.7 33.2 .7 9.3 

1983 .223 17.8 231 118 .543 1.4 25.8 45.9 36.1 .6 4.7 

1984 .239 17.4 224 118 .557 4.9 31.0 42.1 35.1 1.9 .6 2.3 

1985 .254 17.5 224 124 .586 7.1 30.6 37.1 42.2 8.7 3.5 1.1 

1986 .283 18.2 211 123 .621 5.9 30.3 42.7 42.0 21.8 18.7 .7 

1987 .278 18.3 210 131 .654 7.4 31.5 39.9 44.8 33.3 33.6 .3 

1988 .298 17.9 227 141 .650 9.0 33.3 35.5 53.1 43.3 44.4 .2 

1989 .307 17.6 234 146 .653 9.9 32.0 32.7 56.8 45.9 47.6 .2 

1990 .302 17.4 237 151 .668 15.5 31.3 28.1 67.4 55.2 40.8 .2 

1991 .322 17.8 228 150 .681 9.7 35.3 31.0 67.4 55.0 43.2 .1 

1992 .334 17.4 234 155 .685 13.6 31.4 27.3 71.5 65.9 32.5 .1 

1993 .360 17.5 235 162 .710 15.1 29.4 23.3 75.7 73.4 25.7 

1994 .404 17.2 239 166 .717 13.1 36.9 23.5 75.1 77.2 22.5 

1995 .380 17.0 244 168 .715 17.7 40.7 20.5 78.6 79.8 20.2 

1996 .400 17.2 243 179 .757 20.1 37.1 15.6 83.5 99.9 .1 

1997 .424 17.0 248 187 .775 13.9 43.2 14.6 85.0 100.0 .0 

1998 .449 17.1 242 187 .795 18.7 42.0 13.4 86.0 100.0 .0 

1999 .449 16.7 249 197 .814 17.4 44.6 9.1 90.5 100.0 

2000 .449 16.9 242 197 .832 19.4 42.4 8.0 91.7 100.0 4.7 

2001 .461 16.7 243 209 .882 18.5 43.8 6.3 93.4 100.0 9.3 

2002 .485 16.7 244 219 .918 18.5 47.6 4.9 94.7 .0 100.0 16.2 

2003 .496 16.9 243 221 .927 19.2 46.5 4.8 93.7 1.2 100.0 19.8 

2004 .520 16.7 252 236 .953 17.2 52.3 3.7 95.0 1.0 100.0 48.4 33.3 

2005 .495 17.2 245 237 .983 25.7 48.3 3.0 95.0 2.0 99.9 .1 52.8 39.8 .1 

2006 .461 17.6 240 234 .990 25.5 47.5 3.1 93.2 3.5 99.9 .1 62.1 49.9 1.5 

2007 .490 17.7 245 247 1.023 24.5 48.8 3.6 92.5 3.9 99.8 .2 58.3 50.0 1.4 

38 
Table 9 (continued) 

Powertrain Characteristics of 1975 to 2007 Cars and Trucks (Percentage Basis) 

MODEL SALES ADJ ENGINE HP/ DRIVETRAIN TRANSMISSION FUEL METERING MultiYEAR FRAC COMP CID HP CID Front 4wd Manual Lock CVT Port TBI Dsl Valve VVT Hybrid

MPG 

1975 1.000 13.1 293 137 .507 5.3 3.3 23.2 4.1 .2 

1976 1.000 14.2 294 135 .493 4.6 4.8 20.9 2.5 .0 .2 

1977 1.000 15.1 287 136 .510 5.5 4.7 19.8 3.4 .0 .4 

1978 1.000 15.8 266 129 .525 7.4 6.6 23.0 5.2 3.9 .0 .9 

1979 1.000 15.9 252 124 .532 9.2 4.3 25.1 6.7 3.7 .1 2.0 

1980 1.000 19.2 198 104 .574 25.0 4.9 35.4 17.8 5.2 .8 4.3 

1981 1.000 20.5 193 102 .580 31.0 4.0 34.1 33.0 5.1 2.4 5.9 

1982 1.000 21.1 188 103 .593 37.0 4.6 32.8 47.8 5.8 8.0 5.6 

1983 1.000 21.0 193 107 .599 37.0 8.1 30.8 52.1 7.3 14.8 2.7 

1984 1.000 21.0 190 109 .618 42.1 8.2 28.4 52.8 11.9 18.7 1.8 

1985 1.000 21.3 189 114 .650 47.8 9.3 26.5 54.5 18.2 24.8 .9 

1986 1.000 21.8 180 114 .678 52.6 9.3 29.8 53.5 32.5 25.7 .4 

1987 1.000 22.0 175 118 .710 57.7 9.6 29.1 55.4 39.9 31.4 .3 

1988 1.000 21.9 180 123 .726 60.0 10.5 27.6 62.2 50.6 34.3 .1 

1989 1.000 21.4 185 129 .743 60.2 10.5 24.6 65.5 0.1 57.3 33.9 .1 

1990 1.000 21.2 185 135 .781 63.8 10.1 22.2 71.2 70.8 27.0 .1 

1991 1.000 21.2 184 138 .796 59.6 12.3 23.9 71.6 70.6 28.7 .1 

1992 1.000 20.8 191 145 .807 58.4 11.2 20.7 74.8 81.6 17.8 .1 

1993 1.000 20.9 191 147 .809 59.9 11.3 19.8 76.5 85.0 14.6 

1994 1.000 20.4 197 152 .816 55.6 15.2 19.5 77.6 87.7 12.1 

1995 1.000 20.5 196 158 .857 57.6 16.2 17.9 80.7 91.6 8.4 .0 

1996 1.000 20.4 197 164 .878 60.0 15.7 15.1 83.5 99.3 .7 .1 

1997 1.000 20.1 199 169 .890 55.8 19.3 14.0 85.5 99.5 .5 .1 39.6 

1998 1.000 20.1 199 171 .904 56.4 20.1 12.8 86.7 99.8 .1 .1 40.9 

1999 1.000 19.7 203 179 .921 55.8 21.3 10.1 89.4 99.9 .1 .1 43.4 

2000 1.000 19.8 200 181 .942 55.5 20.2 9.7 89.5 99.8 .0 .1 44.8 15.0 

2001 1.000 19.6 201 187 .968 53.8 21.9 9.0 90.2 0.1 99.9 .1 49.0 19.6 

2002 1.000 19.4 203 195 .994 52.7 25.0 8.1 91.3 0.2 99.8 .2 53.3 25.3 

2003 1.000 19.6 204 199 1.007 50.7 25.0 8.0 90.8 1.1 99.8 .2 55.5 30.6 

2004 1.000 19.3 212 211 1.026 47.7 29.8 6.8 91.8 1.1 99.9 .1 62.3 38.5 .5 

2005 1.000 19.9 205 209 1.050 53.0 26.8 6.2 91.5 2.3 99.7 .3 65.6 45.8 1.1 

2006 1.000 20.2 203 212 1.072 53.1 25.0 6.7 90.1 2.9 99.6 .4 72.0 56.0 1.5 

2007 1.000 20.2 210 223 1.091 50.5 27.8 7.7 84.6 7.1 99.9 .1 70.4 59.1 2.2 

39 
Table 10 

MY2007 Technology Usage by Vehicle Type and Size

(Percent of Vehicle Type/Size Strata) 

Front Four 

Vehicle Size Wheel Wheel Manual Multi- Variable 

Type Drive Drive Trans. Valve Valve 

Car Small 70% 7% 23% 91% 65% 

Midsize 86% 5% 6% 90% 85% 

Large 61% 7% 1% 41% 47% 

All 75% 6% 11% 80% 69% 

Wagon Small 94% 5% 16% 100% 70% 

Midsize 31% 53% 8% 84% 30% 

Large 57% 43% 0% 80% 15% 

All 79% 18% 13% 95% 57% 

Van Small 

Midsize 95% 5% 0% 53% 48% 

Large 0% 11% 0% 0% 0% 

All 92% 5% 0% 51% 46% 

SUV Small 0% 89% 26% 29% 2% 

Midsize 30% 59% 3% 83% 61% 

Large 12% 57% 0% 53% 48% 

All 21% 60% 3% 67% 53% 

Pickup Small 

Midsize 0% 27% 27% 70% 77% 

Large 0% 50% 4% 38% 77% 

All 0% 47% 7% 43% 46% 

40 
Figures 35 through 39 show trends in drive use for the five vehicle classes. Cars used to 

be nearly all rear-wheel drive; from 1988 to 2004 they were over 80 percent front-wheel drive 

with a small four-wheel (4WD) drive fraction. In recent years, there has been an increase in the 

use of rear wheel drive from less than 12 percent in 1998 to 17 percent this year, and a slight 

increase in the use of four wheel drive in cars with use of this technology increasing from about 

two percent in the late 1990s to eight percent this year. Only a small percentage of wagons still 

have rear-wheel drive, but in recent years they have made substantial use of 4WD. 

The trend towards increased use of front wheel drive for vans is very similar to that for 

cars, except it started a few years later and appears to be continuing. Over 90 percent of vans 

currently use front-wheel drive, compared to essentially none before 1984. SUVs are mostly 

4WD; but a trend toward front-wheel drive SUVs started in MY2000. Pickups remain the 

bastion of rear-wheel drive with the increasing amount of 4WD the only other drive option. 

Except for a brief period in the early 1980s, front-wheel drive has not been used in pickups. 

Front, Rear and Four Wheel Drive Usage Front, Rear and Four Wheel Drive Usage 

(Three Year Moving Average) (Three Year Moving Average) 

Cars Wagons

Sales Fraction Sales Fraction 100% 100%

1976 1980 1984 1988 1992 1996 2000 2004

Model Year 

Front 

4wd 

Rear 

80% 80% 

60% 60% 

40% 40% 

20% 20% 

0% 0% 

1976 1980 1984 1988 1992 1996 2000 2004 

Model Year 

Front 

4wd 

Rear 

 Figure 35 Figure 36 

41 
Front, Rear and Four Wheel Drive Usage 

(Three Year Moving Average) 

Vans

Sales Fraction 100% 

80% 

60% 

40% 

20% 

0% 

1976 1980 1984 1988 1992 1996 2000 2004 

Model Year 

Front 

4wd 

Rear 

Figure 37 

Front, Rear and Four Wheel Drive Usage

(Three Year Moving Average)

Pickups 

Sales Fraction 100% 

80% 

60% 

40% 

20% 

0% 

1976 1980 1984 1988 1992 1996 2000 2004 

Model Year 

Front 

4wd 

Rear 

 Figure 39 

Front, Rear and Four Wheel Drive Usage

(Three Year Moving Average)

SUVs

Sales Fraction 100% 

80% 

60% 

40% 

20% 

0% 

1976 1980 1984 1988 1992 1996 2000 2004 

Model Year 

Front 

4wd 

Rear 

Figure 38 

42 
Laboratory 55/45 MPG vs 0 to 60 Time

 MY2007 Cars 

Laboratory 55/45 

MPG 

4 6 8 10 12 14 

0 to 60 Time (Sec.) 

I: Faster 0 to 60

 Higher MPG 

II: Slower 0 to 60

 Higher MPG 

IV: Slower 0 to 60

 Lower MPG 

III: Faster 0 to 60

 Lower MPG 

Hybrids 70 

Diesels 

Front 

Rear 

60 

50 4wd 

40 

30 

20 

10 

0 

Figure 40 

Figures 40 and 41 and Tables 11 and 12 give, as an indication of how the different drive 

types are currently used, plots of fuel economy and performance for cars and trucks. The data 

points in these graphs represent sales-weighted averages calculated at estimated 0-to-60 time 

increments of 0.1 sec. The trend lines in these two figures reflect the fuel economy/ 

performance tradeoff for conventionally powered vehicles, on the average. By drawing a 

vertical line at the average performance, and a horizontal line at the average mpg, the space in 

each figure is divided into four areas of better/worse performance crossed with better/worse fuel 

economy 

Table 11 

Distribution of MY2007 Car Sales 

By technology, 0-to-60 time and Lab 55/45 MPG 

0 to 60 time <9.5 Sec >9.5 sec <9.5 sec >9.5 sec 

Lab 55/45 MPG >29.4 MPG >29.4 MPG <29.4 MPG <29.4 MPG 

Vehicle Quadrant Quadrant Quadrant Quadrant

Technology I II III IV 

Front Drive 7% 62% 24% 7% 

Rear Drive 1% 2% 78% 19% 

4wd 0% 2% 54% 44% 

Hybrids 3% 97% 0% 0% 

Diesels 60% 0% 0% 40% 

All Cars 6% 47% 35% 12% 

43 
Laboratory 55/45 MPG vs 0 to 60 Time

 MY2007 Trucks

Laboratory 55/45 

MPG 

4 6 8 10 12 14 

0 to 60 Time (Sec.) 

I: Faster 0 to 60

 Higher MPG 

II: Slower 0 to 60

 Higher MPG 

IV: Slower 0 to 60

 Lower MPG 

III: Faster 0 to 60

 Lower MPG 

Hybrids 70 

Diesels 

Front 

Rear 

60 

50 4wd 

40 

30 

20 

10 

0 

Figure 41 

compared to the average 0 to 60 time and mpg. The vehicles in Quadrant I, for example, have 

faster than average 0- to-60 time and higher than average fuel economy, but this quadrant 

accounts for only six percent of all 2007 car sales and 18 percent of all truck sales. Over 60 

percent of all front wheel drive car sales are in Quadrant II (the Slower/Higher one), as are onehalf of the FWD truck sales, but only two percent of the rear drive and two percent of 4wd cars. 

Over three fourths of the rear drive cars and over half of the 4wd cars are in Quadrant III ( the 

Faster/Lower one) as are half of the rear and four wheel drive trucks. Similar data for 0-to-60 

time and Laboratory Ton MPG are presented in Figures 42 and 43 and Tables 13 and 14. 

Table 12 

Distribution of MY2007 Truck Sales 

By technology, 0-to-60 time and Lab 55/45 M 

0 to 60 time <9.7 Sec >9.7 sec <9.7 sec >9.7 sec 

Lab 55/45 MPG >22.1 MPG >22.1 MPG <22.1 MPG <22.1 MPG 

Vehicle Quadrant Quadrant Quadrant Quadrant

Technology I II III IV 

Front Drive 49% 51% 0% 0% 

Rear Drive 6% 9% 50% 35% 

4wd 9% 15% 51% 24% 

Hybrids 80% 20% 0% 0% 

Diesels 98% 0% 0% 2% 

All Trucks 18% 22% 39% 21% 

44 
Laboratory Ton-MPG vs 0 to 60 Time

 MY2007 Cars

Laboratory 

Ton-MPG 

100 

80 

60 

40 

20 

0 

4 6 8 10 12 14 

0 to 60 Time (Sec.) 

I: Faster 0 to 60

 Higher Ton-MPG 

II: Slower 0 to 60

 Higher Ton-MPG 

IV: Slower 0 to 60

 Lower Ton-MPG 

III: Faster 0 to 60

 Lower Ton-MPG 

Figure 42 

Laboratory Ton-MPG vs 0 to 60 Time

 MY2007 Trucks 

Laboratory

Ton-MPG

100 

80 

60 

40 

20 

0 

4 6 8 10 12 14 

0 to 60 Time (Sec.) 

I: Faster 0 to 60 

Higher Ton-MPG 

II: Slower 0 to 60

 Higher Ton-MPG 

IV: Slower 0 to 60 

Lower Ton-MPG 

III: Faster 0 to 60

 Lower Ton-MPG 

Figure 43 

45 

Hybrids

Diesels

Front 

Rear 

4wd 

Hybrids 

Diesels 

Front 

Rear 

4wd 
Table 13 

Distribution of MY2007 Car Sales 

By technology, 0-to-60 time and Lab Ton-MPG 

0 to 60 time <9.5 Sec >9.5 sec <9.5 sec >9.5 sec 

Lab Ton-MPG >53.8 Ton-MPG >53.8 Ton-MPG <53.8 Ton-MPG <53.8 

Ton-MPG 

Vehicle Quadrant Quadrant Quadrant Quadrant

Technology I II III IV 

Front Drive 6% 46% 25% 23% 

Rear Drive 1% 2% 78% 19% 

4wd 0% 5% 54% 41% 

Hybrids 3% 97% 0% 0% 

Diesels 60% 40% 0% 0% 

All Cars 4% 36% 37% 23% 

Table 14 

Distribution of MY2007 Truck Sales 

By technology, 0-to-60 time and Lab Ton-MPG 

0 to 60 time <9.5 Sec >9.5 sec <9.5 sec >9.5 sec 

Lab Ton-MPG >53.8 Ton-MPG >53.8 Ton-MPG <53.8 Ton-MPG <53.8 

Ton-MPG 

Vehicle Quadrant Quadrant Quadrant Quadrant

Technology I II III IV 

Front Drive 39% 27% 10% 24% 

Rear Drive 20% 19% 36% 25% 

4wd 19% 9% 41% 31% 

Hybrids 80% 20% 0% 0% 

Diesels 100% 0% 0% 0% 

All Trucks 25% 16% 32% 27% 

46 
The increasing trend in Ton-MPG shown in Table 1 can be attributed to better vehicle 

design, including more efficient engines, better transmission designs, and better matching of the 

engine and transmission. Powertrains are matched to the load better when the engine operates 

closer to its best efficiency point more of the time. For many conventional engines, this point is 

approximately 2000 RPM and 2/3 of the maximum torque at that speed. One way to make the 

engine operate more closely to its best efficiency point is to increase the number of gears in the 

transmission and, for automatic transmissions, employing a lockup torque converter. Three 

important changes in transmission design have occurred in recent years: 

1) the use of additional gears for both automatic and manual transmissions, 

2) for the automatics, conversion to lockup (L3, L4, L5, L6 and now L7) torque 

converter transmissions, and 

3) the use of continuously variable transmissions (CVTs). 

Table 15 compares Ton-MPG by transmission and vehicle type for 1988, the peak year 

for passenger car fuel economy, and this year. In 1988, every transmission type shown in the 

table achieved less than 40 Ton-MPG. This year, nearly every transmission type achieves at 

least 40 Ton-MPG. Figures 44 to 47 indicate that the L4 transmission is losing its position as the 

predominant transmission type for all vehicle classes. Use of the L4 transmission for cars 

peaked at about 80 percent in 1999 and is now down to 45 percent. Similarly, its use peaked at 

over 90 percent in 1996 for SUVs and has dropped below the 40 percent level. Over half of this 

year=s pickups will still have L4 transmissions, as will about 60 percent of the vans. Where 

manual transmissions are used, the 5-speed (M5) transmission now predominates. 

Transmissions alter the ratio of engine speed to drive wheel speed. In conventional 

transmissions, this speed ratio is limited to a fixed number of discrete values, but for a CVT, the 

ratio is continuous. These transmissions differ from conventional automatic transmissions and 

manual transmissions in that CVTs do not have a fixed number of gears with the advantage that 

the engine speed/drive wheel speed ratio can be altered to enhance vehicle performance or fuel 

economy in ways not available with conventional transmissions. 

More data stratified by transmission type can be found in Appendix I. 

47 
Transmission Sales Fraction 

(Three Year Moving Average) 

Cars

Sales Fraction 100% 

80% 

60% 

40% 

20% 

0% 

1979 1984 1989 1994 1999 2004 

M5 

A3 

Other 

L4 

M4 

L6 

L3 

L5 

CVT 

Model Year 

 Figure 44 

Transmission Sales Fraction 

(Three Year Moving Average) 

SUVs

Sales Fraction 100% 

80% 

60% 

40% 

20% 

0% 

1980 1985 1990 1995 2000 2005 

L4 

L5 

M4 M5

A3 

M3 

L3 

Other 

CVT 

Model Year 

 Figure 46 

Transmission Sales Fraction 

(Three Year Moving Average) 

Vans 

Sales Fraction 100% 

80% 

60% 

40% 

20% 

0% 

1980 1984 1988 1992 1996 2000 2004 

A3 

L3 

L4 

L5 

M5 M4 

Other 

Model Year 

Figure 45 

Transmission Sales Fraction 

(Three Year Moving Average) 

Pickups

Sales Fraction 

100% 

80% 

60% 

40% 

20% 

0% 

1980 1985 1990 1995 2000 2005 

L4 

L5 

M5 

M4 

A3 

M3 

Other 

Model Year 

 Figure 47 

48 
Table 15 

Ton-MPG by Transmission and Vehicle Type 

(Conventionally Powered Vehicles) 

Car Van SUV Pickup 

Trans 1988 2007 1988 2007 1988 2007 1988 2007 

M4 37.0 -- 33.6 -- 38.0 -- 32.4 --

M5 37.7 40.8 37.7 -- 33.1 41.2 35.3 39.9 

M6 -- 38.9 -- -- -- 36.5 -- 37.7 

CVT -- 44.3 -- 42.9 -- 41.6 -- --

L3 36.1 -- 37.1 -- 33.5 -- 31.4 --

L4 37.9 41.3 36.6 42.7 33.8 41.8 33.8 42.5 

L5 -- 42.6 -- 45.1 -- 40.9 -- 38.4 

L6 -- 42.3 -- -- -- 44.1 -- 44.0 

Table 16 and Figures 48 through 51 compare horsepower (HP), displacement 

(CID), and specific power or horsepower per cubic inch (HP/CID) for cars, vans, 

SUVs, and pickups. For all four vehicle types, significant CID reductions occurred 

in the late 1970s and early 1980s. Engine displacement has been flat for cars and 

vans since the mid-1980s and has been flat for SUVs since the mid-1990s, but has 

been increasing for two decades for pickups. Average horsepower has increased 

substantially for all of these vehicle types since 1981 with the highest increase 

occurring for pickups whose HP is now more than double what it was then (i.e., 268 

versus 115 HP). Light-duty vehicle engines, thus, have also improved in specific 

power with the highest specific power being for engines used in passenger cars. 

Table 16 

MY2007 Engine Characteristics by Vehicle Type 

Vehicle HP CID HP/ Multi- Variable Cylinder

Type CID Valve Valve Deactivation 

Car 200 176 1.16 82% 68% 3% 

Van 224 217 1.04 51% 46% 12% 

SUV 242 232 1.06 67% 53% 11% 

Pickup 268 287 0.93 42% 46% 14% 

All 223 210 1.09 70% 59% 8% 

49 
 Car Horsepower, CID

and Horsepower per CID

(Three Year Moving Average)

HP, CID HP/CID 

360 

CID 

HP 

HP/CID 

1.2 

320 1.1 

280 1.0 

240 0.9 

200 0.8 

160 0.7 

120 0.6 

80 0.5 

40 0.4 

1975 1980 1985 1990 1995 2000 2005 

Model Year 

Figure 48 

SUV Horsepower, CID

and Horsepower per CID

(Three Year Moving Average)

HP, CID HP/CID 

360 

HP 

HP/CID 

CID 

1.2 

320 1.1 

280 1.0 

240 0.9 

200 0.8 

160 0.7 

120 0.6 

80 0.5 

40 0.4 

1975 1980 1985 1990 1995 2000 2005 

Model Year 

Figure 50 

Van Horsepower, CID

 and Horsepower per CID

(Three Year Moving Average)

HP, CID HP/CID 

360 

CID 

HP 

HP/CID 

1.2 

320 1.1 

280 1.0 

240 0.9 

200 0.8 

160 0.7 

120 0.6 

80 0.5 

40 0.4 

1975 1980 1985 1990 1995 2000 2005 

Model Year

 Figure 49

Pickup Horsepower, CID

 and Horsepower per CID 

(Three Year Moving Average)

HP, CID HP/CID 

360 1.2 

320 1.1 

280 1.0 

240 0.9 

200 0.8 

160 0.7 

120 0.6 

80 0.5 

40 0.4 

1975 1980 1985 1990 1995 2000 2005 

Model Year 

 Figure 51 

CID 

HP 

HP/CID 

50 
 Table 17 compares CID, HP, and HP/CID by vehicle type and number of cylinders for 

model years 1988 and 2007. Table 17 shows that the increase in horsepower shown for the fleet 

in Table 9 extends to all vehicle type and cylinder number strata. These increases in horsepower 

range from 50 to over 90% . Because displacement has remained relatively constant, it can be 

seen that the primary reason for the horsepower increase is increased specific power C up 

between 44 and 88% from 1988 to 2007. 

At the number-of-cylinders level of stratification, model year 2007 cars consistently 

achieve higher specific power than vans, SUVs or pickups. One reason for the lower specific 

power of some truck engines is that these vehicles may be used to carry heavy loads or pull 

trailers and thus need more Atorque rise,@ (i.e., an increase in torque as engine speed falls from 

the peak power point) to achieve acceptable drivability. Engines equipped with four valves per 

cylinder typically have inherently lower torque rise than two valve engines with lower specific 

power. 

. 

Table 17 

Changes in Horsepower and Specific Power

by Vehicle Type and Number of Cylinders 

Vehicle HP HP Percent CID CID Percent HP/CID HP/CID Percent 

Type Cyl. 1988 2007 Change 1988 2007 Change 1988 2007 Change 

Cars 4 95 151 59% 118 127 8% 0.805 1.186 47% 

6 142 236 66% 193 206 7% 0.744 1.152 55% 

8 164 316 93% 301 310 3% 0.544 1.021 88% 

Vans 4 98 150 53% 145 148 2% 0.678 1.014 50% 

6 149 224 50% 213 216 1% 0.722 1.039 44% 

8 168 295 76% 322 325 1% 0.520 0.908 75% 

SUVs 4 94 163 73% 122 142 16% 0.773 1.146 48% 

6 147 233 59% 211 216 2% 0.706 1.081 53% 

8 183 308 68% 338 317 -6% 0.541 0.971 80% 

Pickups 4 97 165 70% 142 163 15% 0.685 1.009 47% 

6 142 221 56% 229 236 3% 0.644 0.943 46% 

8 180 299 66% 329 321 -2% 0.544 0.928 71% 

51 
Table 18 

Improvement in Horsepower and Specific Power

by Vehicle Type and Inertia Weight 

Inertia HP HP Percent CID CID Percent HP/CID HP/CID Percent 

Weight 1988 2007 Change 1988 2007 Change 1988 2007 Change 

Cars 

2250 73 199 173% 90 110 22% 0.808 1.810 124% 

2500 78 106 36% 100 91 -9% 0.785 1.165 48% 

2750 97 116 20% 123 101 -18% 0.804 1.145 43% 

3000 114 135 18% 145 118 -19% 0.797 1.141 43% 

3500 151 191 26% 212 163 -23% 0.732 1.185 62% 

4000 160 245 53% 289 211 -27% 0.569 1.179 107% 

4500 144 304 111% 305 302 -1% 0.474 1.007 113% 

5000 207 296 43% 408 268 -34% 0.509 1.093 115% 

5500 205 299 46% 412 236 -43% 0.498 1.258 153% 

6000 205 449 119% 412 329 -20% 0.498 1.326 167% 

Inertia HP HP Percent CID CID Percent HP/CID HP/CID Percent 

Weight 1988 2007 Change 1988 2007 Change 1988 2007 Change 

Vans 

4000 149 181 21% 214 196 -8% 0.717 0.929 30% 

4500 169 233 38% 320 219 -32% 0.528 1.070 103% 

5000 156 210 35% 312 272 -13% 0.500 0.769 54% 

5500 195 295 51% 346 325 -6% 0.562 0.908 61% 

6000 126 295 134% 379 325 -14% 0.332 0.908 173% 

Inertia HP HP Percent CID CID Percent HP/CID HP/CID Percent 

Weight 1988 2007 Change 1988 2007 Change 1988 2007 Change 

SUVs 

3500 147 164 12% 210 148 -30% 0.712 1.109 56% 

4000 135 203 50% 190 190 0% 0.723 1.081 50% 

4500 147 243 65% 311 224 -28% 0.494 1.094 122% 

5000 181 259 43% 330 256 -22% 0.545 1.027 89% 

5500 200 315 58% 350 295 -16% 0.572 1.085 90% 

6000 162 321 98% 368 329 -11% 0.445 0.979 120% 

Inertia HP HP Percent CID CID Percent HP/CID HP/CID Percent 

Weight 1988 2007 Change 1988 2007 Change 1988 2007 Change 

Pickups 

3500 129 156 21% 183 163 -11% 0.719 0.964 34% 

4000 154 201 31% 282 216 -23% 0.555 0.936 68% 

4500 174 235 35% 322 238 -26% 0.539 0.995 85% 

5000 193 262 36% 342 294 -14% 0.565 0.886 57% 

5500 178 302 70% 363 323 -11% 0.495 0.932 88% 

6000 140 318 127% 379 330 -13% 0.369 0.960 160% 

Table 18 shows similar data to that in Table 17, but the stratification is based on inertia 

weight. This table clearly shows that, for every case for which a comparison can be made 

between 1988 and 2007, there were increases in HP, substantial increases in specific power 

ranging from 30 to 170%, and with just minor exceptions, substantial decreases in CID. 

52 
HP/CID by Number of Valves Per Cylinder

(Three Year Moving Average)

Cars

HP/CID

1.2

1.0

0.8

0.6

0.4

4-Valve 

3-Valve 

2-Valve 

4-Valve

3-Valve

2-Valve

198019851990199520002005

Model Year

 Figure 52

HP/CID by Number of Valves Per Cylinder

(Three Year MovingAverage)

SUVs

HP/CID

1.2

1.0

0.8

0.6

0.4

4-Valve 

3-Valve 

2-Valve 

4-Valve

3-Valve

2-Valve

HP/CIDby Number of Valves Per Cylinder

(Three Year Moving Average)

Vans

HP/CID

1.2

1.0

0.8

0.6

0.4

4-Valve 

3-Valve 

2-Valve 

4-Valve

3-Valve

2-Valve

198019851990199520002005

Model Year

Figure 53

HP/CID by Numberof ValvesPer Cylinder

(Three Year MovingAverage)

Pickups

HP/CID

1.2

1.0

0.8

0.6

0.4

4-Valve 

2-Valve 

4-Valve 3-Valve

2-Valve

3-Valve

1980 1985 1990 1995 2000 2005 1980 1985 1990 1995 2000 2005

Model Year Model Year

Figure 54 Figure 55

53 
Number of Valves per Cylinder Number of Valves per Cylinder 

(Three Year Moving Average) (Three Year Moving Average) 

Cars Vans 

1988 1992 1996 2000 2004 

0% 

20% 

40% 

60% 

80% 

100% 

Sales Fraction 

Five 

Four 

Three 

Two 

1988 1992 1996 2000 2004 

0% 

20% 

40% 

60% 

80% 

100% 

Sales Fraction

 Four

 Three

 Two 

Model Year Model Year 

 Figure 56 Figure 57 

Number of Valves per Cylinder Number of Valves per Cylinder 

(Three Year Moving Average) (Three Year Moving Average) 

SUVs Pickups

Sales Fraction 

Two 

Three 

Four 

1988 1992 1996 2000 2004 

Model Year Model Year 

 Figure 58 Figure 59 

1988 1992 1996 2000 2004 

0% 

20% 

40% 

60% 

80% 

100% 

Four 

Three 

Two 

0% 

20% 

40% 

60% 

80% 

100% 

Sales Fraction 

54 
Figures 52 through 55 show that increases in HP per CID apply to all of the engines, 

except for a couple of case for engines with three valves. Engines with more valves per cylinder 

deliver higher values of HP per CID. Engines with only two valves per cylinder deliver 

substantially more horsepower per CID then they used to, typically about a 50 percent increase 

for the time period shown. The increases in HP and HP-per-CID is due to changes in engine 

technologies. Figures 56 through 59 show that usage of multi-valve engines is increasing for all 

vehicle types and as shown in Table 16 for MY2007, is now over 80 percent for cars, nearly 70 

percent for SUVs, and about 45 percent for pickups and vans. 

Figures 60 and 61 and Table 19 show how the car and truck fleet have evolved from one 

that consisted almost entirely of carbureted engines to one which is now almost entirely port fuel 

injected, with a clear trend towards increased use of variable valve timing. In 1975, about 95 

percent of all cars had carburetors as did almost all of the trucks, by 1988 use of carburetors had 

dropped below the 20 percent level for all vehicle types. For MY2007, nearly 70 percent of cars 

have multi-valve, port fuel injected engines with variable valve timing, as do about half of 

SUVs, vans, and pickups. 

Car Sales Fraction by Engine Type Truck Sales Fraction by Engine Type 

(Three Year Moving Average) (Three Year Moving Average) 

Sales Fraction Sales Fraction 100% 100% 

80% 80% 

60% 60% 

40% 40% 

20% 20% 

0% 0% 

Diesel 

Carb. 

TBI. 

Port VVT 

Port Fixed 

Valve 

Diesel 

TBI. 

Carb. 

Port VVT 

Port Fixed 

Valve 

1976 1980 1984 1988 1992 1996 2000 2004 1976 1980 1984 1988 1992 1996 2000 2004 

Model Year Model Year 

Figure 60 Figure 61 

55 
Table 19 

Sales Fraction of MY1988 and MY2007 Light Vehicles

by Engine Type and Valve Timing 

Engine Type Cars Vans SUVs Pickups All 

1988 2007 1988 2007 1988 2007 1988 2007 1988 2007 

Carb 16% --- <1% --- 16% --- 16% --- 15% ---

TBI 30% --- 43% --- 37% --- 48% --- 34% ---

Port Fixed 54% 32% 57% 54% 47% 47% 36% 54 51% 41% 

Port Variable --- 65% --- 46% --- 51% --- 46 --- 57% 

Diesel <1% <1% <1% --- <1% <1% <1% --- <1% <1% 

Hybrids --- 3% --- --- --- 2% --- <1% --- 2% 

For over a decade and an half, automotive manufacturers have been using engines which 

use either cams or electric solenoids to provide variable intake and/ or exhaust valve timing and 

in some cases valve lift. Conventional engines use camshafts which are permanently 

synchronized with the engine's crankshaft so that they operate the valves at a specific fixed point 

in each combustion cycle regardless of the speed and load at which the engine is operated. The 

ability to control valve timing allows the design of an engine combustion chamber with a higher 

compression level than in engines equipped with fixed valve timing engines which in turn 

provides greater engine efficiency, more power and improved combustion efficiency. Variable 

valve timing (VVT) also allows the valves to be operated at different points in the combustion 

cycle, to provide performance that is precisely tailored to the engine's specific speed and load at 

any given instant with the valve timing set to allow the best overall performance across the 

engine's normal operating range. This results in improved engine efficiency under low-load 

conditions, such as at idle or highway cruising, and increased power at times of high demand. In 

addition, variable valve timing can result in reduced pumping losses, from the work required to 

pull air in and push exhaust out of the cylinder. 

Because automobile manufacturers are not currently required to provide EPA with data 

on the type of valve timing their engines have, the data base used to generate EPA=s fuel 

economy trend report was augmented to indicate whether a vehicle had fixed or variable valve 

timing. The data augmentation was based on data from trade publications and data published by 

automotive manufacturers. In addition, no differentiation between engines which used cams or 

solenoids to control the valve timing was made, nor was valve lift considered. For cars, the 

augmented data covers model years 1989 to 2007, while for trucks the augmentation covered 

model years 1999 to 2007. 

56 
Table 20 

Comparison of MY1988 and MY2007 Cars

by Engine Fuel Metering, Number of Valves and Valve Timing 

Fuel Number Valve Horsepower CID HP/CID Ton MPG 0 to 60 

Metering of Timing Time 

Valves 

1988 2007 1988 2007 1988 2007 1988 2007 1988 2007 

Carb Fixed 88 --- 131 --- .75 --- 37.2 --- 14.3 ---

TBI 2 Fixed 97 --- 141 --- .71 --- 36.9 --- 13.7 ---

Port 2 Fixed 136 261 193 285 .74 .92 36.6 40.4 11.9 8.6 

Port 4 Fixed 137 189 131 162 1.05 1.18 37.9 40.2 11.1 9.8 

Port 4 Variable --- 194 --- 157 --- 1.22 --- 42.6 --- 9.6 

Percent Change over 1988 Port Two Valve, Fixed Valve Timing 

Carb Fixed -35% --- -32% --- 1% --- 2% --- 20% ---

TBI 2 Fixed -29% --- -27% --- -4% --- 1% --- 15% ---

Port 2 Fixed 0% 92% 0% 48% 0% 24% 0% 10% 0% -28% 

Port 4 Fixed 1% 38% -32% -16% 42% 59% 4% 10% -7% -18% 

Port 4 Variable --- 43% --- -19% --- 65% --- 16% --- -19% 

Table 20 compares horsepower, engine size (CID), specific power (HP/CID), Ton- mpg, 

and estimated 0-to-60 acceleration time for five selected MY1988 and 2007 engine types. 

Because 1988 was the peak year for car fuel economy, and because the two valve, fixed 

valve timing, port injected engine accounted for about half of the car engines built that year, it 

was selected as a base line engine with its average characteristics compared to those for the 

MY2007 two- and four-valve, fixed valve timing and four- valve VVT engines. As shown in 

Figure 62, all three of these MY2007 engine types had substantially higher horsepower than the 

baseline MY1988 engine, but the MY2007 four valve engines fixed and VVT engines are 

considerably smaller and have substantially higher specific power. Not all of these 

improvements in engine design for these engine types that occurred between 1988 and 2007 

were used to improve fuel economy as indicated by the nominal 20 percent decrease in 0-to-60 

time each achieved. As mentioned earlier, in this report vehicle performance for conventionally 

powered vehicles is determined by an estimate of 0-to-60 acceleration time calculated from the 

ratio of vehicle power to weight. Obtaining increased power to weight in a time when weight is 

trending upwards implies that horsepower is increasing. Increased horsepower can be obtained 

by increasing the engine=s displacement, the engine=s specific power (HP/CID), or both. 

Increasing specific power has been the primary driver for increases in performance for the past 

two decades. 

57 
Percent Difference in MY2007 Vehicle Characteristics 

From MY1988 Port 2 Valve Fixed Car Engine

Percent Change 

100% 

MY 2007 Engine Type 

Port 4 Valve Variable 

80% Port 4 Valve Fixed 

Port 2 Valve Fixed 

60% 

40% 

20% 

0% 

-20% 

-40%

Ton MPG 0 to 60 Time HP CID HP/CID Figure 62 

For the current model year fleet, specific power has been studied at an even more detailed 

level of stratification with both car and truck engines being classified according to: (1) the 

number of valves per cylinder, (2) the manufacturer=s fuel recommendation, (3) the presence or 

absence of an intake boost device such as a turbocharger or supercharger and (4) whether or not 

the engine had fixed or variable valve timing. (See Tables 21 and 22.) Higher HP/CID is 

associated with: (a) more valves per cylinder, (b) higher octane fuel, (c) intake boost and (4) use 

of variable valve timing. The technical approaches result in specific power ranges for cars and 

trucks from about .9 to about 1.7. The relative sales fractions in Tables 21 and 22 are just for 

each technical option in the table and exclude hybrids. 

Tables 21 and 22 show the incremental effect, on a sales weighted basis, of adding each 

technical option, but not all of the technical options are sales significant. The effect of the use of 

higher octane fuel cannot be discounted, because roughly 20 percent of the current car fleet is 

comprised of vehicles which use engines for which high octane fuel is recommended. By 

comparison, about 12 percent of this year=s light trucks require premium fuel. 

Engine technology which delivers improved specific power thus can be used in many 

ways ranging from reduced displacement and improved fuel economy at constant (or worse) 

performance, to increased performance and the same fuel economy at constant displacement. 

58 
Table 21 

HP/CID and Sales Fraction by Fuel and Engine Technology 

Model Year 2007 Cars 

Number of Valves per Cylinder 

Fuel/Boost/Valves Two Three Four Five Total 

HP/CID Sales HP/CID Sales HP/CID Sales HP/CID Sales Sales 

Fract. Fract. Fract. Fract. Fract. 

Regular/No Boost/FIX .88 .088 ---- ---- 1.11 .175 1.35 ---- .263 

Regular/No Boost/VVT 1.02 .077 1.07 .010 1.15 .414 ---- ---- .501 

Regular/Boost /FIX ---- ---- ---- ---- ---- ---- ---- ---- .000 

Regular/Boost /VVT ---- ---- ---- ---- 1.52 .001 ---- ---- .001 

Premium/No Boost/FIX 1.16 .013 .89 .001 1.22 .013 1.35 ---- .027 

Premium/No Boost/VVT ---- ---- ---- ---- 1.31 .160 ---- ---- .160 

Premium/Boost /FIX 1.08 .001 1.52 .001 1.62 .028 ---- ---- .030 

Premium/Boost /VVT ---- ---- 1.52 ---- 1.67 .017 ---- ---- .017 

Diesel/No Boost ---- ---- ---- ---- ---- ---- ---- ---- .000 

Diesel/Boost ---- ---- ---- ---- 1.16 .001 ---- ---- .001 

Total .179 .012 .808 ---- 1.000 

Table 22 

HP/CID and Sales Fraction by Fuel and Engine Technology 

Model Year 2007 Trucks 

Number of Valves per Cylinder 

Fuel/Boost/Valves Two Three Four Five Total 

HP/CID Sales HP/CID Sales HP/CID Sales HP/CID Sales Sales 

Fract. Fract. Fract. Fract. Fract. 

Regular/No Boost/FIX 0.90 0.371 1.04 0.009 1.10 0.099 ---- ---- 0.480 

Regular/No Boost/VVT 0.97 0.027 0.91 0.056 1.10 0.310 ---- ---- 0.393 

Regular/Boost /FIX ---- ---- ---- ---- ---- ---- ---- ---- 0.000 

Regular/Boost /VVT ---- ---- ---- ---- 1.53 0.001 ---- ---- 0.001 

Premium/No Boost/FIX 1.02 0.006 0.99 0.001 1.18 0.012 ---- ---- 0.019 

Premium/No Boost/VVT 1.06 0.012 ---- ---- 1.18 0.088 ---- ---- 0.100 

Premium/Boost /FIX ---- ---- 1.48 ---- ---- ---- ---- ---- 0.000 

Premium/Boost /VVT ---- ---- 1.35 ---- 1.70 0.005 ---- ---- 0.005 

Diesel/No Boost ---- ---- ---- ---- ---- ---- ---- ---- 0.000 

Diesel/Boost 1.03 ---- ---- ---- 1.18 0.002 ---- ---- 0.002 

Total 0.417 0.066 0.517 ---- 1.000 

59 
A recent engine development has been the reintroduction of cylinder deactivation, an 

automotive technology that was used by General Motors in some MY1981 V-8 engines that 

could be operated in 8- , 6- and 4-cylinder modes. This approach, which has also been called by 

a number of names including >variable displacement=, >displacement on demand=, >active fuel 

management= and >multiple displacement=, involves allowing the valves of selected cylinders of 

the engine to remain closed and interrupting the fuel supply to these cylinders when engine 

power demands are below a predetermined threshold, as typically happens under less demanding 

driving conditions, such as steady state operation. Under light load conditions, the engine can 

thus provide better fuel mileage than would otherwise be achieved. Although frictional and 

thermodynamic energy losses still occur in the cylinders that are not being used, these losses are 

more than offset by the increased load and reduced specific fuel consumption of the remaining 

cylinders. Typically half of the usual number of cylinders are deactivated. Challenges to the 

engine designer for this type of engine include mode transitions, idle quality, and noise and 

vibration. For MY2007, as shown previously in Table 16, it is estimated that about three percent 

of cars and about 12 percent of trucks are equipped with cylinder deactivation. 

Table 23 

Comparison of MY2007 Cars with Engines with Cylinder Deactivation 

Car Model Name Drive Trans Inertia Engine Lab. Cyl. Pct. Change

Class Weight CID HP 55/45 Deact. HP MPG 

Midsize Grand Prix Front L4 4000 325 290 25.1 Yes 16% -2% 

Car Grand Prix 231 250 25.5 No 

Large Impala Front L4 4000 325 290 24.7 Yes 21% -4% 

Car Impala 237 240 25.6 No 

300 AWD 4wd L5 4500 348 340 23.1 Yes 34% 1% 

300 AWD 215 253 22.8 No 

Midsize Magnum AWD 4wd L5 4500 348 340 23.1 Yes 34% 1% 

Wagon Magnum AWD 215 253 22.8 No 

60 
 Table 24 

Comparison of MY2007 Trucks with Engines with Cylinder Deactivation 

Truck Model Name Drive Trans Inertia Engine Lab. Cyl. Pct. Change

Class Weight CID HP 55/45 Deact. HP MPG 

Midsize Odyssey Front L5 4500 212 244 25.0 Yes 0% 5% 

Van Odyssey 212 244 23.9 No 

Midsize Grand Cherokee Rear L5 5000 348 345 19.5 Yes 50% -1% 

SUV Grand Cherokee 287 230 19.7 No 

Large Envoy 4wd L4 5000 325 280 20.0 Yes 2% -3% 

SUV Envoy 254 275 20.6 No 

Durango Rear L5 5000 348 345 19.5 Yes 47% 7% 

Durango Rear L5 5000 287 235 18.3 No 

Large Ram 1500 Rear L5 5000 348 345 19.5 Yes 47% 7% 

Pickup Ram 1500 287 235 18.3 No 

Ram 1500 4wd L5 5500 348 345 18.8 Yes 47% 11% 

Ram 1500 287 235 17.0 No 

Table 23 compares examples of individual MY2007 car models with cylinder deactivation with 

their same-model counterparts with optional smaller engines that do not incorporate cylinder 

deactivation. For every case in the table, the version of the model equipped with cylinder 

deactivation has horsepower ratings that are significantly higher and about the same fuel 

economy. Some of the truck examples in Table 24 indicate that models equipped with cylinder 

deactivation can achieve both higher horsepower and fuel economy than their counterparts. 

The data in Tables 23 and 24 indicate cylinder deactivation can be used to increase fuel economy 

at constant horsepower, or to maintain equivalent fuel economy at higher horsepower levels, or, 

in some cases, to increase both horsepower and fuel economy. 

61 
Car Technology Penetration

Years After First Significant Use

Sales Fraction 

100% 

75% 

50% 

25% 

0% 

0 5 10 15 20 25 30 35 

Years 

Port FI Lockup 

Multivalve Front Drive 

Variable 

Valve 

Continuously Variable Transmission 

Figure 63 

Figure 63 compares penetration rates for six passenger car technologies, namely port fuel 

injection (Port FI), front-wheel drive (FWD), multi-valve engines (i.e., engines with more than 

two valves per cylinder), lockup transmissions, engines with variable valve timing, and CVTs. 

The sales fraction for VVT car engines has increased in a similar fashion to the others shown in 

the figure. This indicates that, in the past, it has taken a decade for a technology to prove itself 

and attain a sales fraction of 40 to 50 percent and as long as another five or ten years to reach 

maximum market penetration. 

62 
Car Technology Penetration 

Years After First Significant Use 

Sales Fraction 

0 5 10 15 20 25 30 35 

Years 

Figure 64 

0% 

25% 

50% 

75% 

100% 

TBI L3 

L4 

Port 2 Valve 

Fixed 

Port 4 Valve 

Fixed 

 A similar comparison of five technologies whose sales fraction peaked out is shown in 

Figure 64. This figure shows that, in the past, it has taken a number of years for technologies 

such as throttle body fuel injection (TBI), lockup 3-speed (L3) and 4-speed (L4) transmissions to 

reach their maximum sales fraction, and, even then, use of these technologies has often 

continued for a decade or longer. For the limited number of historical cases studied, the time a 

given technology has taken to attain and then pass a market share of about 40 to 50 percent 

appears to be one indicator of whether it later attains a stabilized high level of market 

penetration. L4 transmissions and both two- and four-valve, port injected, fixed valve timing car 

engines (Port 2V- and 4V- Fixed) now can be classified with technologies such as TBI engines 

and L3 transmissions which have reached their peak sales fractions and, thus, are likely to 

disappear from the new vehicle fleet. 

63 
Table 25 compares inertia weight, the fuel economy ratings, the ratio of highway to city 

fuel economy, and ton-mpg of the MY2007 hybrid and diesel vehicles with those for the average 

conventionally powered MY2007 car and truck. All of the hybrid and diesel vehicles in the 

table have a lower highway/city ratio than the average conventional car or truck. 

Table 25 

Characteristics of MY 2007 Hybrid and Diesel Vehicles 

Inertia Lab <----- Adjusted -----> HWY/

Model Name Weight CID Trans 55/45 City HWY COMP City TonMPG MPG MPG MPG Ratio MPG 

Hybrid Cars 

Prius 3000 91 CVT 65.8 47.7 45.1 46.2 .95 69.3 

Altima 3500 152 CVT 46.7 35.1 33.0 33.9 .94 59.3 

Accord 4000 183 L5 36.3 24.4 32.1 28.3 1.31 56.5 

Gs 450H 4500 211 L6 30.8 21.9 25.3 23.7 1.15 53.4 

Civic 3000 82 CVT 58.8 40.2 45.3 42.9 1.13 64.4 

Camry 4000 144 CVT 45.9 33.4 34.1 33.8 1.02 67.6 

Hybrid Trucks 

Vue 3500 145 L4 34.0 23.3 29.3 26.4 1.26 46.2 

RX 400H 2WD 4500 202 CVT 35.0 27.5 24.5 25.7 .89 57.9 

Mariner 4WD 4000 140 CVT 36.4 27.6 26.7 27.1 .97 54.1 

Highlander 4WD 4500 202 CVT 34.3 26.5 24.6 25.4 .93 57.1 

Highlander 2WD 4500 202 CVT 35.0 27.5 24.5 25.7 .89 57.9 

Escape FWD 4000 140 CVT 40.6 31.3 28.5 29.7 .91 59.3 

Escape 4WD 4000 140 CVT 36.4 27.6 26.7 27.1 .97 54.1 

RX 400H 4Wd 4500 202 CVT 34.3 26.5 24.6 25.4 .93 57.1 

K15 Silverado classic 4WD 5500 325 L4 20.9 14.9 18.0 16.5 1.21 45.5 

K15 Sierra classic 4WD 5500 325 L4 20.9 14.9 18.0 16.5 1.21 45.5 

C15 Silverado classic 2WD 5000 325 L4 22.3 15.9 19.2 17.6 1.20 44.0 

C15 Sierra classic 2WD 5000 325 L4 22.3 15.9 19.2 17.6 1.20 44.0 

Diesel Cars 

R320 CDI 4MATIC 5500 182 L7 28.2 19.0 25.9 22.4 1.36 61.5 

E320 BLUETEC 4000 182 L7 34.7 22.8 32.2 27.3 1.41 54.7 

Diesel Trucks 

Touareg 6000 300 L6 21.7 14.8 20.0 17.4 1.35 52.2 

GL320 CDI 4MATIC 6000 182 L7 26.1 17.9 23.4 20.7 1.30 62.0 

Grand Cherokee 4WD 5000 183 L5 25.1 17.5 22.1 19.8 1.27 49.6 

Grand Cherokee 2WD 4500 183 L5 26.0 17.9 23.0 20.5 1.28 46.2 

ML320 CDI 4MATIC 5000 182 L7 27.5 18.9 24.4 21.7 1.29 54.2 

Average Car 3588 176 -- 29.4 19.5 27.6 23.4 1.42 42.6 

Average Truck 4722 245 -- 22.1 15.1 20.4 17.7 1.35 42.0 

64 
In addition, there are several cases in the table for which the highway to city ratio is less than 

1.0, and these represent cases where a vehicle achieves higher fuel economy in city than in 

highway driving. This year=s diesel cars achieve ton-mpg values that are roughly the same as 

some of the hybrid cars. For MY2007, the Toyota Prius achieves 79 Ton-mpg, almost twice that 

of the average car. 

All but two of the vehicles in Table 25 (the Toyota Prius and GL320 CDI 4MATIC) 

have conventionally powered counterparts. Tables 26 and 27 compare the adjusted composite 

fuel economy and an estimate of annual fuel usage (assuming 15,000 miles per year) for these 

vehicles with their conventionally powered (baseline) counterparts. The comparisons in both 

tables are limited to a basis of: model name, drive, inertia weight, transmission, and engine size 

(CID), and for simplicity there is only one listing for Atwin@ vehicles, namely: the Escape/ 

Mariner, the GM C15-K15 Silverado/ Sierra pickups and the Highlander/ RX400 H. Differences 

in the performance attributes of these vehicles complicate making the forward analysis of the 

fuel economy improvement potential due to hybridization and dieselization. In particular, hybrid 

vehicles are often reported to have faster 0-to-60 acceleration times than their conventional 

counterparts, while vehicles equipped with diesel engines have higher low-end 

Table 26 

Comparison of MY2007 Hybrid Vehicles With Their Conventional Counterparts 

<----- Hybrid Version ------> <---- Baseline Version ---> <Improvement> 

Model Name Inertia ADJ Gal Inertia ADJ Gal ADJ Gal 

Weight CID Trans COMP Per Weight CID Trans COMP Per COMP Per 

MPG Year* MPG Year* MPG Year* 

Accord 4000 183 L5 28.3 530 3500 183 L5 22.0 682 29% 152 

Altima 3500 152 CVT 33.9 442 3500 152 CVT 26.9 558 26% 115 

Civic 3000 82 CVT 42.9 350 3000 110 L5 29.6 507 45% 157 

Camry 4000 144 CVT 33.8 444 3500 144 L5 25.4 591 33% 147 

Vue 3500 145 L4 26.4 568 3500 134 L4 22.8 657 16% 90 

Escape FWD 4000 140 CVT 29.7 505 3500 140 L4 21.9 685 36% 180 

3500 140 M5 23.8 630 25% 125 

Escape 4WD 4000 140 CVT 27.1 554 3500 140 L4 20.5 732 32% 178 

3500 140 M5 22.4 670 21% 116 

Highlander 2WD 4500 202 CVT 25.7 584 4000 202 L5 19.9 754 29% 170 

Highlander 4WD 4500 202 CVT 25.4 591 4500 202 L5 19.2 781 32% 191 

C15 Silverado Classic 2WD 5000 325 L4 17.6 852 5000 325 L4 16.8 893 5% 41 

K15 Silverado Classic 4WD 5500 325 L4 16.5 909 5500 325 L4 16.4 915 1% 6 

*Note: 

Gallons per year calculation is based on all vehicles being driven 15,000 miles. 

65 
torque, but slower 0-to-60 times. In addition, some hybrid vehicles use technologies such as 

cylinder deactivation and CVT transmissions that are not offered in their counterparts. Given the 

difficulty in choosing the Aright@ baseline vehicle, Table 25 thus typically includes a comparison 

for the CVT-equipped Escape Hybrid with baseline data for both manual and automatic 

transmission versions of this vehicle. 

Fuel economy improvements and fuel savings per year for the hybrid vehicles in Table 

26 vary considerably from about five percent for the GM pickups to 45 percent for the CVTequipped Civic hybrid. Similarly, fuel economy improvements for diesels range from 16 to 35 

percent, and these vehicles also offer relatively high savings in fuel usage. Several years after 

the introduction for sale in the U.S. of the first hybrid vehicle, the MY2000 Honda Insight, 

hybrid vehicles now account for over two percent of the combined car/truck fleet. In addition, 

the sales fraction for diesels remains below a quarter of one percent, more than an order of 

magnitude smaller than their 5.9 percent sales fraction in 1981. 

Table 27 

Comparison of MY2007 Diesel Vehicles With Their Conventional Counterparts 

<----- Hybrid Version -----> <----- Baseline Version -----> <Improvement> 

Model Name Inertia ADJ Gal Inertia ADJ Gal ADJ Gal 

Weight CID Trans COMP Per Weight CID Trans COMP Per COMP Per 

MPG Year* MPG Year* MPG Year* 

E320 BLUETEC** 4000 182 L7 27.3 549 4000 213 L7 20.2 743 35% 193 

R320 CDI 4MATIC** 5500 182 L7 22.4 670 5500 213 L7 17.0 882 32% 213 

ML320 CDI 4MATIC** 5000 182 L7 21.7 691 5000 213 L7 17.4 862 25% 171 

Touareg 6000 300 L6 17.4 862 5500 254 L6 14.8 1014 18% 151 

Grand Cherokee 4WD 5000 183 L5 19.8 758 4500 226 L5 17.1 877 16% 120 

Grand Cherokee 2WD 4500 215 L5 20.5 732 4500 226 L5 17.7 847 16% 116 

*Note: 

Gallons per year calculation is based on all vehicles being driven 15,000 miles. 

**Note: 

Baseline version used for the E320 BLUETEC comparison is the E350. Baseline version used for the R320 CDI

4MATIC comparison is the R350 4MATIC. Baseline version used for the ML320 CDI 4MATIC comparison is the

ML350 4MATIC. 

66 
VI. Marketing Groups 

In its century of evolution, the automotive industry existed first as small, individual 

companies that relatively quickly went out of business or grew into larger corporations. In that 

context, the historic term >manufacturer= usually meant a corporation that was associated with a 

single country that manufactured vehicles for sale in just that country and perhaps exported 

vehicles to a few other countries, too. Over the years, the nature of the automotive industry has 

changed substantially, and it has evolved into one in which global consolidations and alliances 

among heretofore independent manufacturers have become the norm, rather than the exception. 

The reports in this series include analyses of fuel economy trends in terms of the whole 

fleet of cars and light trucks and in various subcategories of interest, e.g., by weight class, by 

size class, etc. In addition, there has been a treatment of trends by groups of manufacturers. 

Initially, these groups were derived from the ADomestic@ and AImport@ categories which are part 

of the automobile fuel economy standards categories. This classification approach evolved into 

a market segment approach in which cars were apportioned to a ADomestic,@ AEuropean,@ and 

AAsian@ category, with trucks classified as ADomestic@ or AImported.@ As the automotive 

industry has become more transnational in nature, this type of vehicle classification has become 

less useful. In this report, trends by groups of manufacturers are now used to reflect the 

transnational and transregional nature of the automobile industry. To reflect the transition to an 

industry in which there are only a small number of independent companies, the fleet has been 

divided into eight major marketing group segments, and an ninth catch-all group (AOthers@) that 

contains independent manufacturers not assigned to one of the eight major marketing groups. 

These eight major marketing groups are: 

1) The General Motors Group includes GM, Opel, Saab, Isuzu, and Daewoo; 

2) The Ford Motor Group includes Ford, Jaguar, Volvo, Land Rover, Aston Martin, and 

Mazda; 

3) The DaimlerChrysler Group includes Chrysler and Mercedes Benz; 

4) The Toyota Group includes Toyota, Scion and Lexus; 

5) The Honda Group includes Honda and Acura; 

6) The Nissan Group includes Nissan and Infiniti; 

7) The Hyundai-Kia (HK) Group includes Hyundai and Kia; and 

8) The VW Group includes Volkswagen, Audi, SEAT, Skoda, Porsche, Lamborghini, 

Buggati, and Bentley. 

67 
Taken together, the eight major marketing groups comprise over 95 percent of the MY2007 new 

vehicle market in the U.S. It is expected that these marketing groups will continue to evolve and 

perhaps expand, or possibly contract as further changes in the automotive industry occur. For 

example, GM sold nearly its entire interest in Suzuki in 2006, and so Suzuki has been deleted 

from the GM marketing group in this year’s report. More recently, Ford sold its interest in 

Aston Martin, and Daimler sold most of its stake in Chrysler. 

Table 28 compares laboratory fuel economy values for the marketing groups described 

above for model year 2007 with the overall fleet average. For each marketing group, the table 

also shows the effect of adding certain individual manufacturers in that group. For example, if 

just GM cars were considered, the GM group would have an average laboratory car fuel 

economy of 27.9 mpg. Adding Daewoo raises GM’s car laboratory value to 28.1 mpg. Adding 

Saab and Isuzu does not change the value further. Toyota, Honda, and Hyundai-Kia have the 

highest laboratory fuel economy values, while GM, Ford, and DC have the lowest values. DC is 

the only marketing group with over 60 percent truck share, while VW is the only one with less 

than 40 percent truck share. Table 29 presents similar data to that in Table 28, except this table 

uses adjusted fuel economy values. 

A more detailed comparison of model year 2007 laboratory fuel economy, by vehicle 

type and size, is presented in Table 30. Stratifying by marketing group, vehicle type and size 

for MY2007, Toyota has the highest laboratory fuel economy average in four of the ten classes 

in which there is widespread competition, Honda leads in three classes, and GM, HK, and VW 

each lead in one class. Table 31 is a companion table to Table 30, but like Table 29 uses adjusted 

mpg data. 

Figures 65 through 72 compare for model years 1975 to 2007: percent truck, laboratory 

55/45 fuel economy for cars, trucks, and both cars and trucks for the GM, Ford, 

DaimlerChrysler, Toyota, Honda, Hyundai-Kia, Nissan, and VW marketing groups, respectively. 

 For all of these marketing groups, combined car and truck fuel economy is lower now than it 

was in 1988. Because the absolute values of fuel economy differ somewhat across the marketing 

groups, a separate presentation of the fuel economy trends was prepared by normalizing the fuel 

economy for each Group by its fuel economy in 1988, the year in which fuel economy for the 

fleet as a whole was the highest. In this way, a relative measure of how each group, compared to 

its own value in 1988, can be seen. The results are shown in Figures 73 through 80. 

All the marketing groups have lower absolute fuel economy now than they did in 1988. 

The declines are similar, except the VW Group has not declined as much, due at least in part to 

the fact their truck share (shown on Figure 72) has remained very low. More information 

stratified by marketing group can be found in the Appendixes L through O. 

68 
Table 28 

Model Year 2007 Laboratory 55/45 Fuel Economy by Marketing Group 

<-- FUEL ECONOMY --> Percent 

Group Group Member Added Cars Trucks Both Truck 

GM GM 27.9 21.3 23.8 55% 

Above plus Daewoo

Above plus Saab

Above plus Isuzu 

28.1 

28.1 

28.1 

21.3 

21.3 

21.3 

24.0 

24.0 

24.0 

53% 

53% 

53% 

Entire GM Group 28.1 21.3 24.0 53% 

Ford Ford 26.6 20.7 22.8 59% 

Above plus Mazda

Above plus Volvo

Above plus Land Rover

Above plus Jaguar

Above plus Ast. Mart. 

27.3 

27.3 

27.3 

27.3 

27.2 

20.8 

20.8 

20.6 

20.6 

20.6 

23.4 

23.4 

23.3 

23.3 

23.3 

54% 

52% 

53% 

53% 

53% 

Entire Ford Group 27.2 20.6 23.3 53% 

DC Chrysler

Above plus Mercedes 

25.6 

25.1 

21.5 

21.5 

22.8 

22.7 

66% 

61% 

Entire DC Group 25.1 21.5 22.7 61% 

Toyota Toyota 34.8 24.1 29.0 46% 

Honda Honda 33.4 25.0 28.7 48% 

Nissan Nissan 31.2 21.2 25.8 44% 

HK Kia 33.3 23.9 27.7 52% 

Above plus Hyundai 32.3 24.5 28.6 41% 

VW VW 28.9 19.7 27.4 11% 

Above plus Porsche 28.6 19.7 27.0 13% 

Above plus Bentley 28.3 19.7 26.7 13% 

Others 27.6 24.7 26.7 27% 

All Fleet Average 29.4 22.1 25.3 49% 

69 
Table 29 

Model Year 2007 Adjusted Composite Fuel Economy by Marketing Group 

Percent 

Group 

GM 

Group Member Added 

GM 

Above plus Daewoo

Above plus Saab

Above plus Isuzu 

Entire GM Group 

<-- FUEL ECONOMY --> 

Cars Trucks Both 

22.4 17.2 19.2 

22.6 17.2 19.4 

22.6 17.2 19.4 

22.6 17.2 19.4 

22.6 17.2 19.4 

Truck 

55% 

53% 

53% 

53% 

51% 

Ford 

DC 

Ford 

Above plus Volvo

Above plus Mazda 

Above plus Jaguar

Above plus Land Rover 

Above plus Ast. Mart. 

Entire Ford Group 

Chrysler

Above plus Mercedes 

Entire DC Group 

21.4 

21.9 

21.9 

21.8 

21.9 

21.8 

21.8 

20.5 

20.1 

20.1 

16.7 

16.7 

16.7 

16.6 

16.6 

16.6 

16.6 

17.3 

17.3 

17.3 

18.3 

18.8 

18.8 

18.7 

18.7 

18.7 

18.7 

18.3 

18.3 

18.3 

59% 

52% 

54% 

53% 

53% 

53% 

53% 

66% 

61% 

61% 

Toyota Toyota 27.2 19.1 22.8 46% 

Honda Honda 26.4 20.0 22.9 48% 

Nissan Nissan 24.6 17.0 20.6 44% 

HK Kia 

Above plus Hyundai 

26.2 

25.6 

19.1 

19.5 

22.0 

22.7 

52% 

41% 

VW VW 

Above plus Porsche

Above plus Bentley 

23.1 

22.9 

22.6 

15.8 

15.9 

15.8 

21.9 

21.6 

21.4 

11% 

13% 

13% 

Others 22.1 19.7 21.4 27% 

All Fleet Average 23.4 17.7 20.2 49% 

70 
Table 30 

Model Year 2007 Laboratory 55/45 Fuel Economy by Marketing Group 

VEHICLE 

TYPE/SIZE GM Ford DC Toyota Honda Nissan HK VW Others All 

Cars 

Small 29.5 29.0 27.5 34.0 37.8 25.2 35.4 28.7 28.2 30.3 

Midsize 27.2 28.0 27.6 35.1 30.1 32.3 34.8 26.1 26.2 30.8 

Large 26.5 24.2 22.8 29.8 23.5 28.6 23.6 22.3 25.3 

All 27.8 27.2 25.2 34.3 33.1 31.2 32.4 28.2 27.4 29.3 

Wagons 

Small 31.5 28.6 27.6 36.4 40.0 29.8 29.0 33.2 

Midsize 26.5 28.4 23.0 27.6 28.5 27.8 26.7 

Large 22.3 22.3 

All 31.5 28.4 24.6 36.4 40.0 27.6 29.0 28.3 30.4 

All Cars 

Small 29.8 29.0 27.5 35.3 38.0 25.2 35.4 28.7 28.2 30.8 

Midsize 27.2 28.0 26.6 35.1 30.1 32.3 34.5 26.7 26.8 30.5 

Large 26.5 24.2 22.6 29.8 23.5 28.6 23.6 22.3 25.1 

All 28.1 27.2 25.1 34.8 33.4 31.2 32.3 28.3 27.6 29.4 

Vans 

Small 0.0 

Midsize 24.5 24.6 24.6 25.9 24.7 24.4 23.8 24.7 

Large 19.7 19.7 

All 22.9 24.6 24.6 25.9 24.7 24.4 23.8 24.6 

SUVs 

Small 20.7 28.6 22.6 

Midsize 27.4 25.4 22.0 25.8 25.5 21.4 24.8 23.6 24.6 

Large 21.2 19.9 19.3 18.7 21.8 23.1 19.7 23.4 20.8 

All 21.6 21.5 21.2 25.2 25.5 21.7 24.7 19.7 24.7 22.6 

Pickups 

Small 0.0 

Midsize 23.4 22.3 24.6 23.7 

Large 20.5 18.8 19.2 19.8 21.4 19.6 20.1 19.7 

All 20.6 19.3 19.2 21.7 21.4 19.6 20.1 20.1 

Fleet 

All 24.0 23.3 22.7 29.0 28.7 25.8 28.6 26.7 26.7 25.3 

71 
 Table 31 

VEHICLE 

TYPE/SIZE 

Cars 

GM 

Model Year 2007 Adjusted Composite Fuel Economy by Marketing Group 

Ford DC Toyota Honda Nissan HK VW Others All 

Small 

Midsize 

Large 

All 

23.6 

22.0 

21.5 

22.4 

23.1 

22.4 

19.6 

21.8 

21.8 

22.1 

18.5 

20.3 

26.6 

27.5 

23.8 

26.9 

29.5 

24.0 

26.2 

20.2 

25.4 

18.9 

24.6 

27.7 

27.3 

23.0 

25.6 

22.9 

21.0 

19.0 

22.6 

22.5 

21.1 

18.1 

22.0 

24.0 

24.5 

20.5 

23.4 

Wagons 

Small 

Midsize 

Large 

All 

24.8 

21.5 

24.8 

22.9 

22.6 

22.6 

21.8 

18.7 

18.1 

19.7 

28.2 

28.2 

30.7 

30.7 

22.0 

22.0 

23.7 

22.8 

23.2 

23.0 

22.1 

22.4 

25.9 

21.4 

18.1 

24.0 

All Cars 

Small 

Midsize 

Large 

All 

23.8 

22.0 

21.5 

22.6 

23.1 

22.4 

19.6 

21.8 

21.8 

21.4 

18.4 

20.1 

27.4 

27.5 

23.8 

27.2 

29.6 

24.0 

26.4 

20.2 

25.4 

18.9 

24.6 

27.7 

27.1 

23.0 

25.6 

23.0 

21.5 

19.0 

22.6 

22.6 

21.5 

18.1 

22.1 

24.4 

24.3 

20.3 

23.4 

Vans 

Small 

Midsize 

Large 

All 

19.8 

15.8 

18.4 

19.7 

19.7 

19.8 

19.8 

20.6 

20.6 

20.0 

20.0 

19.7 

19.7 

19.2 

19.2 

0.0 

19.9 

15.8 

19.8 

SUVs 

Small 

Midsize 

Large 

All 

21.9 

17.2 

17.5 

20.0 

16.2 

17.4 

16.5 

17.7 

15.5 

17.0 

20.3 

14.9 

19.8 

20.3 

20.3 

17.2 

17.5 

17.4 

19.7 

18.7 

19.7 

15.9 

15.9 

22.5 

18.8 

18.8 

19.7 

17.9 

19.5 

16.8 

18.1 

Pickups 

Small 

Midsize 

Large 

All 

18.9 

16.4 

16.6 

17.8 

15.2 

15.5 

15.5 

15.5 

19.5 

15.9 

17.3 

17.2 

17.2 

15.8 

15.8 

16.2 

16.2 

0.0 

18.8 

15.8 

16.2 

Fleet 

All 19.4 18.7 18.3 22.8 22.9 20.6 22.7 21.4 21.4 20.2 

72 
150%

200%

250%

300%

150%

200%

250%

300%

150%

200%

250%

300%

150%

200%

250%

300%

GM Marketing Group Ford Marketing Group 

Fuel Economy by Model Year Fuel Economy by Model Year 

(Three Year Moving Average) (Three Year Moving Average)

Laboratory 55/45 MPG Percent Truck Laboratory 55/45 MPG Percent Truck 

Cars 

Both 

Trucks 

Percent Truck 

Model Year Model Year

Figure 65 Figure 66

1975 1980 1985 1990 1995 2000 2005 

10 

15 

20 

25 

30 

35 

40 

0% 

50% 

100% 

Cars 

Both 

Trucks 

Percent Truck 

1975 1980 1985 1990 1995 2000 2005 

10 

15 

20 

25 

30 

35 

40 

0% 

50% 

100% 

DaimlerChrysler Marketing Group Toyota Marketing Group 

Fuel Economy by Model Year Fuel Economy by Model Year 

(Three Year Moving Average) (Three Year Moving Average)

Laboratory 55/45 MPG Percent Truck 40 

Laboratory 55/45 MPG Percent Truck 

40

35 35

30 30

25 25

20 100% 20 100%

50% 15 50% 15

0% 10 10 0%

1975 1980 1985 1990 1995 2000 2005 1975 1980 1985 1990 1995 2000 2005

Model Year Model Year

 Figure 68

 Figure 67

Cars 

Both 

Trucks 

Percent Truck 

Cars 

Both 

Trucks 

Percent Truck 

73 
150%

200%

250%

300%

150%

200%

250%

300%

150%

200%

250%

300%

150%

200%

250%

300%

Honda Marketing Group

Fuel Economy by Model Year

(Three Year Moving Average)

Laboratory 55/45 MPG Percent Truck 

40

35

30

25

20

Cars 

Both 

Trucks 

Percent Truck 

100%

15 50%

10 0% 

1975 1980 1985 1990 1995 2000 2005

Model Year

 Figure 69

Hyundai-Kia Marketing Group

Fuel Economy by Model Year

(Three Year Moving Average)

Laboratory 55/45 MPG Percent Truck 

40

35

30

25

20

Cars 

Both 

Trucks 

Percent Truck 

100%

15 50%

10 0% 

1975 1980 1985 1990 1995 2000 2005

Model Year

 Figure 71

Nissan Marketing Group

Fuel Economy by Model Year

(Three Year Moving Average)

Laboratory 55/45 MPG Percent Truck 

40

35

30

25

20

Cars 

Both 

Trucks 

Percent Truck 

100%

15 50%

10 0% 

1975 1980 1985 1990 1995 2000 2005

Model Year

 Figure 70

VW Marketing Group

Fuel Economy by Model Year

(Three Year Moving Average)

Laboratory 55/45 MPG Percent Truck 

40

35

30

25

20 100% 

Cars 

Trucks 

Both 

Trucks

15 50% 

Percent Truck 

10 0% 

1975 1980 1985 1990 1995 2000 2005

Model Year

 Figure 72

74 
Normalized Fuel Economy Normalized Fuel Economy

 GM Marketing Group Ford Marketing Group

(Three Year Moving Average) (Three Year Moving Average)

Both Cars and Trucks Both Cars and Trucks 

0.50 

0.75 

1.00 

1.25 

Normalized Fuel Economy (1988 = 1.00) 

GM 

All 

0.50 

0.75 

1.00 

1.25 

Normalized Fuel Economy (1988 = 1.00) 

Ford 

All 

1975 1980 1985 1990 1995 2000 2005 1975 1980 1985 1990 1995 2000 2005 

Model Year Model Year Figure 73 Figure 74 

Normalized Fuel Economy

 DC Marketing Group 

(Three Year Moving Average) 

Both Cars and Trucks 

1.25 

Normalized Fuel Economy (1988 = 1.00) 

Normalized Fuel Economy

 Toyota Marketing Group 

(Three Year Moving Average) 

1.25 

Normalized Fuel Economy (1988 = 1.00) 

Both Cars and Trucks 

1.00 1.00 

0.75 0.75 

Figure 75 

1975 1980 

0.50 

1985 1990 1995 

Model Year 

2000 2005 

Figure 76 

1975 1980 

0.50 

1985 1990 1995 

Model Year 

2000 2005 

DC 

All 

Toyota 

All 

75 
Honda 

All 

Nissan 

All 

Hyundai-Kia 

All 

VW 

All 

Normalized Fuel Economy

 Honda Marketing Group 

(Three Year Moving Average) 

Both Cars and Trucks 

1.25 

Normalized Fuel Economy (1988 = 1.00) 1.25 

Normalized Fuel Economy

 Nissan Marketing Group 

(Three Year Moving Average) 

Normalized Fuel Economy (1988 = 1.00) 

Both Cars and Trucks 

1.00 1.00 

0.75 0.75 

Figure 77 

1975 1980 

0.50 

1985 1990 1995 

Model Year 

2000 2005 

Figure 78 

1975 1980 

0.50 

1985 1990 1995 

Model Year 

2000 2005 

1.25 

Normalized Fuel Economy

 Hyundai-Kia Marketing Group 

(Three Year Moving Average) 

Normalized Fuel Economy (1988 = 1.00) 

Both Cars and Trucks 

1.25 

Normalized Fuel Economy

 VW Marketing Group 

(Three Year Moving Average) 

Both Cars and Trucks 

Normalized Fuel Economy (1988 = 1.00) 

1.00 1.00 

0.75 0.75 

Figure 79 

1975 1980 

0.50 

1985 1990 1995 

Model Year 

2000 2005 

Figure 80 

1975 1980 

0.50 

1985 1990 1995 

Model Year 

2000 2005 

76 
VII. Characteristics of Fleets Comprised of Existing Fuel-Efficient Vehicles 

This section is limited to a discussion of hypothetical fleets of vehicles comprised of 

existing fuel-efficient vehicles and the fuel economy and other characteristics of those fleets. 

While it includes a discussion of some of the technical and engineering factors that affect fleet 

fuel economy, it does not attempt to evaluate either the benefits or the costs of achieving various 

fuel economy levels. In addition, the analysis presented here also does not attempt to evaluate 

the marketability or the public acceptance of any of the hypothetical fleets that result from the 

scenarios studied and discussed below. 

There are several different ways to look at the potential for improved fuel economy from 

the light-duty vehicle fleet. Many of these approaches utilize projections of more fuel efficient 

technologies that are not currently being used in the fleet today. As an example, a fleet made up 

of a large fraction of fuel cell vehicles could be considered. Such projections can be associated 

with a good deal of uncertainty, since uncertainty in the projections of market share compound 

with uncertainties about the fuel economy performance of yet uncommercialized technology. 

These uncertainties can be thought of as a combination of technical risk, i.e., can the technology 

be developed and mass produced?, and market risk, i.e., will people buy vehicles with the 

improved fuel economy? 

One general approach used in this report is to consider only the fuel economy 

performance of those technologies which exist in today=s fleet. This eliminates uncertainty about 

the feasibility and production readiness of the technology and reduces or eliminates the technical 

risk but, as mentioned above, does not treat market risk. Therefore, the analysis can be thought 

of as the fuel economy potential now in the fleet, with no new technologies added, if the higher 

mpg choices available were to be selected. 

As was shown in Figures 3 and 4, there is a wide distribution of fuel economy. Because 

of the interest in the high end of this spectrum, this portion of the database was examined in 

more detail using three Abest in class@ (BIC) analysis techniques. This type of technique is not 

new, and in fact was one of the methods used to investigate future fleet fuel economy capability 

when the original fuel economy standards were set. 

In any group or class of vehicles there will be a distribution of fuel economy 

performance, and the Abest in class@ method relies on that fact. The analysis involves dividing 

the fleet of vehicles into classes, selecting a set of representative high mpg Arole model@ vehicles 

from each class, and then calculating the average characteristics of the resultant fleet using the 

same relative sales proportions as in the baseline fleet. 

One potential problem with a BIC analysis is that the high mpg cars used in the analysis 

may be unusual in some way C so unusual that the hypothetical fleet made up of them may be 

deficient in some other attributes considered desirable by vehicle buyers. Because the BIC 

analysis is also sensitive to the selection of the best vehicles, three different procedures were 

used to select the role models. 

77 
Two of these selection procedures use the EPA car size classes (which for cars are the 

same as those used for the EPA/DOE Fuel Economy Guide) and the truck type/size classes 

described previously in this report. The third best-in-class role model selection procedure is 

based on using the vehicle inertia weight classes used for EPA=s vehicle testing and certification 

process. 

The advantage of using and analyzing data from the best-in-size class methods is that if 

the sales proportions of each class are held constant, the sales distribution of the resultant fleet 

by vehicle type and size does not change. This means that the size of the average vehicle does 

not change a lot, but there can be some fluctuation in interior volume for cars because of the 

distribution of interior volume within a car class. Similarly, there also is an advantage in using 

the inertia weight classes to determine the role models, since, if the sales proportions in each 

inertia weight class are held constant, the sales distribution of the resultant fleet by weight does 

not change, and in this case, the average weight remains the same. 

 One way of performing a best-in-class analysis is to use as role models the four 

nameplates with the highest fuel economy in each size class. (See Tables Q-1 and Q-2 in 

Appendix Q.) Under this procedure, all vehicles in a class with the same nameplate are included 

as role models regardless of vehicle configuration. Each role model nameplate from each class 

was assigned the same sales weighting factor, but the original sales weighting distribution for 

different vehicle configurations within a given nameplate (e.g., transmission type, engine size, 

and/or drive type) was retained. The resulting values were used to recalculate the fleet average 

values using the same relative proportions in each of the size classes that constitute the fleet. In 

cases where two identical vehicles differ by only one characteristic but have slightly different 

nameplates (such as the two-wheel drive Chevrolet C1500 and the four-wheel drive Chevrolet 

K1500 pickups), both are considered to have the different nameplates. Conversely, in the cases 

where there are technically identical vehicles with different nameplates (e.g., the Buick LeSabre 

and Pontiac Bonneville sedans), only one representative vehicle nameplate was considered in the 

BIC analysis. 

The second best-in-class role model selection procedure involves selecting as role models 

the best dozen vehicles in each size class with each vehicle configuration considered separately. 

Tables Q-3 and Q-4 in Appendix Q give listings of the representative vehicles used in this 

method. As with the previous procedure, in cases where technically identical vehicle 

configurations have different nameplates, only one representative vehicle was considered. 

Under this best-in-class method, the sales data for each role model vehicle in each class was 

assigned the same value, and the resulting values were used to re-calculate the fleet values again 

using the same relative proportions in each of the size classes that constitute the fleet. 

78 
The third best-in-class procedure involves selecting as role models the best dozen 

vehicles in each weight class. As with the previous method, each vehicle configuration was 

considered separately. (See Tables Q-5 and Q-6 in Appendix Q for a listing of the vehicles used 

in this analysis.) It should be noted that some of the weight classes have less than a dozen 

representative vehicles. In addition, as in the previous two best-in-class methods, where 

technically identical vehicle configurations with different nameplates are used, only one 

representative vehicle was included. As with the two best-in-size class methods, the sales data 

for each role model vehicle in each class was assigned the same value, and the resulting values 

were used to recalculate the fleet values again using the same relative proportions in each of the 

size classes that constitute the fleet. 

Tables 32 to 34 compare, for cars, trucks, and both cars and trucks, respectively, the 

results of the best-in-class analysis with actual average data for model year 2007. As discussed 

earlier, for the size class scenarios, the percentage of vehicles that are small, midsize, or large are 

the same as for the baseline fleet, and in the weight class scenarios, the average weight of the 

BIC data sets is the same as the actual one. 

Under all of the best-in-class scenarios, the vehicles used for the BIC analysis have less 

powerful engines, have slower 0-to-60 acceleration times, and are more likely to be equipped 

with front wheel drive, VVT, CVTs, and hybrid powertrains than the entire fleet as a whole. For 

trucks, the BIC data set vehicles make greater use of these same technologies plus multi-valve 

engines. 

For both cars and trucks in MY2007, depending on the scenario chosen, cars could have 

achieved from 16 to 31 percent better fuel economy than they did. Similarly, for trucks the fuel 

economy improvement ranges from 11 to 23 percent better fuel economy, and the combined car 

and truck fleet could have been 12 to 32 percent better. 

The best-in-class analyses can be thought of as the mpg potential now in the fleet with no 

new technologies added if the higher mpg choices available were selected. As such, the best-inclass analyses provide a useful reference point indicating the variation in fuel economy levels 

that results in large part from consumer preferences as opposed to technological availability. 

79 
Table 32 

Best in Class Results 2007 Cars 

Vehicle Selection Actual Size Size Weight

Characteristic Basis Data Class Class Class 

Selection All Best 4 Best 12 Best 12 

Criteria Cars Nameplates Vehicles Vehicles 

Fuel Economy Lab. 55/45 29.4 38.5 36.5 34.1 

Adjusted City 19.5 25.9 24.4 22.8 

Adjusted Highway 27.6 33.5 32.4 30.8 

Adjusted Composite 23.4 29.7 28.4 26.7 

Vehicle Size Weight (lb.) 3588 3217 3210 3588 

Volume (Cu. Ft) 111 111 111 114 

Engine CID 176 129 131 155 

HP 200 141 146 187 

HP/CID 1.16 1.10 1.12 1.20 

HP/WT .055 .043 .045 .051 

Percent Multivalve 82% 86% 87% 97% 

Percent Variable Valve 68% 89% 83% 86% 

Percent Diesel 0.1% <0.1% <0.1% 0.4% 

Performance 0-60 Time (Sec.) 9.5 10.3 10.4 9.7 

Top Speed 138 121 123 133 

Ton-MPG 43.2 50.0 47.0 48.8 

Cu. Ft. Mpg 2732 3479 3273 3134 

Cu. Ft. Ton-MPG 4829 5547 5215 5549 

Drive Front 75% 96% 95% 89% 

Rear 8% 2% 4% 8% 

4WD 17% 2% 2% 3% 

Transmission Manual 12% 11% 15% 12% 

Lockup 77% 59% 59% 50% 

CVT 10% 29% 24% 38% 

Hybrid Vehicle 3.0% 28.5% 17.0% 12.6% 

80 
Table 33 

Best in Class Results 2007 Trucks 

Vehicle Selection Actual Size Size Weight

Characteristic Basis Data Class Class Class 

Selection All Best 4 Best 12 Best 12 

Criteria Trucks Nameplates Vehicles Vehicles 

Fuel Economy Lab. 55/45 22.1 27.2 26.0 24.6 

Adjusted City 15.1 19.0 17.8 16.7 

Adjusted Highway 20.4 23.5 23.4 22.7 

Adjusted Composite 17.7 21.3 20.6 19.7 

Vehicle Size Weight (lb.) 4723 4164 4087 4723 

Engine CID 245 198 195 221 

HP 247 195 203 241 

HP/CID 1.02 0.99 1.05 1.11 

HP/WT .052 .047 .050 .051 

Percent Multivalve 58% 61% 72% 69% 

Percent Variable Valve 50% 66% 71% 68% 

Percent Diesel 0.2% 1.2% 0.5% 1.6% 

Performance 0-60 Time (Sec.) 9.7 9.7 9.9 9.8 

Top Speed 140 130 133 138 

Ton-MPG 42.0 45.4 42.5 46.3 

Drive Front 25% 49% 54% 39% 

Rear 27% 28% 19% 19% 

4WD 49% 24% 28% 42% 

Transmission Manual 4% 5% 9% 3% 

Lockup 93% 54% 72% 91% 

CVT 4% 41% 19% 7% 

Hybrid Vehicle 1.4% 30.4% 8.1% 3.8% 

81 
Table 34 

Best in Class Results 2007 Light Duty Vehicles 

Vehicle Selection Actual Size Size Weight

Characteristic Basis Data Class Class Class 

Selection All Best 4 Best 12 Best 12 

Criteria Vehicles Nameplates Vehicles Vehicles 

Fuel Economy Lab. 55/45 25.3 33.4 31.3 28.3 

Adjusted City 17.1 22.8 21.2 19.1 

Adjusted Highway 23.6 29.0 28.0 25.9 

Adjusted Composite 20.2 26.0 24.6 22.5 

Vehicle Size Weight (lb.) 4144 3565 3571 4144 

Engine CID 210 154 157 190 

HP 223 161 169 215 

HP/CID 1.10 1.06 1.09 1.15 

HP/WT .053 .045 .047 .051 

Percent Multivalve 70% 77% 81% 82% 

Percent Variable Valve 59% 80% 78% 77% 

Percent Diesel 0.1% 0.5% 0.2% 1.0% 

Performance 0-60 Time (Sec.) 9.6 10.1 10.2 9.8 

Top Speed 139 124 127 135 

Ton-MPG 42.6 48.3 45.1 47.5 

Drive Front 51% 79% 78% 62% 

Rear 22% 12% 10% 14% 

4WD 28% 10% 12% 24% 

Transmission Manual 8% 9% 13% 7% 

Lockup 85% 58% 65% 72% 

CVT 7% 33% 22% 22% 

Hybrid Vehicle 2.2% 29.2% 13.3% 7.9% 

82 
Another general approach for determining potential fuel economy improvement is to 

study the effects on fuel economy caused by the changes that have occurred in the distributions 

of vehicle weight and size. This technique involves preserving the average characteristics of 

vehicles within each size or weight strata in today=s fleet, but re-mixing the sales distributions to 

match those of a baseline year and then calculating the fleet wide averages for those 

characteristics using the re-mixed sales data. The sales distribution of the resultant fleet by 

vehicle type and size, thus is forced to be the same as that for the base year. As with the best in 

car size class technique, there can be some fluctuation in average interior volume for cars 

because of the distribution of interior volume within a car class. Similarly, if the sales 

proportions in each inertia weight class are held the same as the base year=s, the sales distribution 

of the resultant fleet by weight remains the same as that for the base year change, and the 

recalculated average weight is the same as the base year=s. In should be noted that both hybrid 

and diesel vehicles were excluded from the analysis so that only vehicles with conventional 

powertrains were considered 

Table 35 compares laboratory fuel economy, weight, interior volume, engine CID and 

HP, estimated 0-to-60 time and fuel economy for conventionally powered MY2007 cars as 

calculated from the actual 2007 sales distribution and then recalculated using the size and weight 

distributions from MY1981 and MY1988. The base years of 1981 and 1988 were chosen 

because 1981 was the year with the lowest average weight and horsepower levels, and 1988 was 

the year with the highest LAB fuel economy. This table includes the actual 1981 and 1988 fleet 

Table 35 

Characteristics of MY 2007 Cars 

Inertia Interior Engine 0 to 60 Lab 55/45

Calculated From: Weight Volume CID HP Time MPG 

2007 Actual Distribution 3598 111 178 203 9.4 29.0 

1981 Weight Distribution 3043 99 137 168 9.7 32.9 

1988 Weight Distribution 3047 103 131 154 10.3 33.9 

1981 Size Distribution 3517 108 171 199 9.4 29.4 

1988 Size Distribution 3516 108 169 196 9.5 29.3 

Reference: 1981 Actual 3043 106 178 99 14.1 24.9 

Reference: 1988 Actual 3047 107 160 116 12.8 28.6 

Percent Change: 

2007 Actual Distribution 0% 0% 0% 0% 0% 0% 

1981 Weight Distribution -15% -11% -23% -17% 3% 13% 

1988 Weight Distribution -15% -7% -26% -24% 10% 17% 

1981 Size Distribution -2% -3% -4% -2% 0% 1% 

1988 Size Distribution -2% -3% -5% -3% 1% 1% 

Reference: 1981 Actual -15% -5% 0% -51% 50% -14% 

Reference: 1988 Actual -15% -4% -10% -43% 36% -1% 

83 
averages as a point of reference. In both of the weight distribution cases, the fuel 

economy of the re-mixed 2007 fleet would have been higher than actually is: 13% if the 

1981 weight distribution is used, 17% if the 1988 weight distribution is used. For both 

re-mixed weight cases, interior volume is smaller by 11 and 7 percent, respectively, and 

horsepower substantially lower. Using the MY1981 and MY1988 size mix 

distributions results in a much smaller change of only a one percent increase in car fuel 

economy. In addition both of these remixed car class scenarios results in an average 

weight and horsepower for the hypothetical remixed fleets that is very close to the 

actual 2007 data. 

Table 36 shows similar data for trucks, and as with the car class cases using 

either the 1981 or the 1988 sales distribution by weight class, results in higher 

recalculated fuel economy than using the corresponding size class sales distribution. 

Figures 81 to 84 compare actual fuel economy for all model years from 1975 to 2007 

with what it would have been had the distributions of weight or size been the same as 

1981 or 1988. For both cars and trucks, using either the 1981 or 1988 weight class 

distribution, results in significantly high fuel economy improvements than the similar 

size class cases. 

Table 36 

Characteristics of MY 2007 Trucks 

Inertia Engine 0 to 60 Lab 55/45

Calculated From: Weight CID HP Time MPG 

2007 Actual Distribution 4728 246 248 9.7 22.0 

1981 Weight Distribution 3841 180 198 9.9 29.8 

1988 Weight Distribution 3838 180 190 10.3 29.1 

1981 Size Distribution 4442 246 242 9.8 22.2 

1988 Size Distribution 4301 226 223 10.0 23.0 

Reference: 1981 Actual 3841 252 121 14.4 19.7 

Reference: 1988 Actual 3838 227 141 12.9 21.2 

Percent Change: 

2007 Actual Distribution 0% 0% 0% 0% 0% 

1981 Weight Distribution -19% -27% -20% 2% 35% 

1988 Weight Distribution -19% -27% -23% 6% 32% 

1981 Size Distribution -6% 0% -2% 1% 1% 

1988 Size Distribution -9% -8% -10% 3% 5% 

Reference: 1981 Actual -19% 2% -51% 48% -10% 

Reference: 1988 Actual -19% -8% -43% 33% -4% 

84 
Effect of Weight and Size On Car Fuel Economy 

 Lab 55/45 MPG 

40 

35 

30 

25 

20 

15 

Distribution 

Actual 

1981 Weight 

1981 Size

10

1970 1975 1980 1985 1990 1995 2000 2005 2010

Model Year

Figure 81

Effect of Weight and Size On Truck Fuel Economy 

40 

35 

30 

25 

20 

15 

10 

 Lab 55/45 MPG 

Distribution 

Actual 

1981 Weight 

1981 Size 

1970 1975 1980 1985 1990 1995 2000 2005 2010 

Model Year

Figure 82 

85 
Effect of Weight and Size On Car Fuel Economy 

 Lab 55/45 MPG 

40 

35 

30 

25 

20 

15 

Distribution 

Actual 

1988 Weight 

1988 Size

10

1970 1975 1980 1985 1990 1995 2000 2005 2010

Model Year

Figure 83

Effect of Weight and Size On Truck Fuel Economy 

40 

35 

30 

25 

20 

15 

10 

 Lab 55/45 MPG 

Distribution 

Actual 

1988 Weight 

1988 Size 

1970 1975 1980 1985 1990 1995 2000 2005 2010 

Model Year

Figure 84 

86 
VIII. References 

1. AU.S. Environmental Protection Agency, Fuel Economy and Emission Control,@ November 

1972. 

2. "Passenger Car Fuel Economy - Trends and Influencing Factors," SAE Paper 730790, Austin 

and Hellman, September 1973. 

3. "Fuel Economy of the 1975 Models," SAE Paper 740970, Austin and Hellman, October 1974. 

4. "Passenger Car Fuel Economy Trends Through 1976," SAE Paper 750957, Austin and 

Service, October 1975. 

5. "Light-Duty Automotive Fuel Economy Trends Through 1977," SAE Paper 760795, Murrell, 

Pace, Service, and Yeager, October 1976. 

6. "Light-Duty Automotive Fuel Economy Trends Through 1978," SAE Paper 780036, Murrell, 

February 1978. 

7. "Light-Duty Automotive Fuel Economy Trends Through 1979," SAE Paper 790225, Murrell, 

February 1979. 

8. "Light-Duty Automotive Fuel Economy Trends Through 1980," SAE Paper 800853, Murrell, 

Foster and Bristor, June 1980. 

9. "Light-Duty Automotive Fuel Economy Trends Through 1981," SAE Paper 810386, Foster, 

Murrell and Loos, February 1981. 

10. "Light-Duty Automotive Fuel Economy Trends Through 1982," SAE Paper 820300, Cheng, 

LeBaron, Murrell, and Loos, February 1982. 

11. AWhy Vehicles Don't Achieve EPA MPG On the Road and How That Shortfall Can Be 

Accounted For," SAE Paper 820791, Hellman and Murrell, June 1982. 

12. ALight-Duty Automobile Fuel Economy Trends through 1983," SAE Paper 830544, Murrell, 

Loos, Heavenrich, and Cheng, February 1983. 

13. "Passenger Car Fuel Economy - Trends Through 1984," SAE Paper 840499, Heavenrich, 

Murrell, Cheng, and Loos, February 1984. 

14. "Light Truck Fuel Economy - Trends through 1984," SAE Paper 841405, Loos, Cheng, 

Murrell and Heavenrich, October 1984. 

87 
15. "Light-Duty Automotive Fuel Economy - Trends Through 1985," SAE Paper 850550, 

Heavenrich, Murrell, Cheng, and Loos, March 1985. 

16. "Light-Duty Automotive Trends Through 1986," SAE Paper 860366, Heavenrich, Cheng, 

and Murrell, February 1986. 

17. "Trends in Alternate Measures of Vehicle Fuel Economy," SAE Paper 861426, Hellman and 

Murrell, September 1986. 

18. "Light-Duty Automotive Trends Through 1987," SAE Paper 871088, Heavenrich, Murrell, 

and Cheng, May 1987. 

19. "Light-Duty Automotive Trends Through 1988," U.S. EPA, EPA/AA/CTAB/88-07, 

Heavenrich and Murrell, June 1988. 

20. "Light-Duty Automotive and Technology Trends Through 1989," U.S. EPA, 

EPA/AA/CTAB/89-04, Heavenrich, Murrell, and Hellman, May 1989. 

21. "Downward Trend in Passenger Car Fuel Economy--A View of Recent Data," U.S. EPA, 

EPA/AA/CTAB/90-01, Murrell and Heavenrich, January 1990. 

22. "Options for Controlling the Global Warming Impact from Motor Vehicles," U.S. EPA, 

EPA/AA/CTAB/89-08, Heavenrich, Murrell, and Hellman, December 1989. 

23. "Light-Duty Automotive Technology and Fuel Economy Trends Through 1990," U.S. EPA, 

EPA/AA/CTAB/90-03, Heavenrich and Murrell, June 1990. 

24. "Light-Duty Automotive Technology and Fuel Economy Trends Through 1991," U.S. 

EPA/AA/CTAB/91-02, Heavenrich, Murrell, and Hellman, May 1991. 

25. "Light-Duty Automotive Technology and Fuel Economy Trends Through 1993," U.S. 

EPA/AA/TDG/93-01, Murrell, Hellman, and Heavenrich, May 1993. 

26. "Light-Duty Automotive Technology and Fuel Economy Trends Through 1996," U.S. 

EPA/AA/TDSG/96-01, Heavenrich and Hellman, July 1996. 

27. "Light-Duty Automotive Technology and Fuel Economy Trends Through 1999," U.S.. 

EPA420-R-99-018, Heavenrich and Hellman, September 1999. 

28. "Light-Duty Automotive Technology and Fuel Economy Trends 1975 Through 2000," U.S. 

EPA420-R-00-008, Heavenrich and Hellman, December 2000. 

88 
29. "Light-Duty Automotive Technology and Fuel Economy Trends 1975 Through 2001," U.S. 

EPA420-R-01-008, Heavenrich and Hellman, September 2001. 

30. "Light-Duty Automotive Technology and Fuel Economy Trends 1975 Through 2003," U.S. 

EPA420-R-03-006, Heavenrich and Hellman, April 2003. 

31. "Light-Duty Automotive Technology and Fuel Economy Trends 1975 Through 2004," U.S. 

EPA420-R-04-001, Heavenrich and Hellman, April 2004. 

32. "Light-Duty Automotive Technology and Fuel Economy Trends 1975 Through 2005,” U.S. 

EPA420-R-05-001, Robert M. Heavenrich, July 2005. 

33. “Light-Duty Automotive Technology and Fuel Economy Trends 1975 Through 2006,” U.S. 

EPA420-R-06-011, Robert M. Heavenrich, July 2006. 

34. AConcise Description of Auto Fuel Economy in Recent Years," SAE Paper 760045, 

Malliaris, Hsia and Gould, February 1976. 

35. AAutomotive Engine B A Future Perspective@, SAE Paper 891666, Amann, 1989. 

36. ARegression Analysis of Acceleration Performance of Light-Duty Vehicles,@ DOT HS 807 

763, Young, September 1991. 

37. ADeterminates of Multiple Measures of Acceleration,@ SAE Paper 931805, Santini and 

Anderson, 1993. 

89