Vehicle Comparison Strategy: 

Eligibility for a High Occupancy Vehicle 

(HOV) Facility Exemption Based on the 

Energy-Effiecient Provision of the 2005 

Transportation Act 

Draft Technical Support Document 
Vehicle Comparison Strategy:


Eligibility for a High Occupancy Vehicle 


(HOV) Facility Exemption Based on the 


Energy-Effiecient Provision of the 2005 


Transportation Act


Draft Technical Support Document


Compliance and Innovative Strategies Division 

Office of Transportation and Air Quality 

U.S. Environmental Protection Agency 

EPA420-D-07-005 

May 2007 
Table of Contents 

Chapter 1: Background on the Safe, Accountable, Flexible Efficient Transportation 
 

Equity Act: A Legacy for Users........................................................................................ 3
 

Chapter 2: Discussion of Potential Vehicle Comparison Strategies ............................... 4
 

2.1 Hybrid-to-Gasoline Vehicle Comparison Method .............................................. 6
 

2.2 Inertia Weight Class Method............................................................................. 8
 

2.3 Hybrid-to-“Best in Class” Method.................................................................... 28
 

2.4 Final Recommendation ................................................................................... 36
 

Chapter 3: List of Eligible Vehicles Based on the Hybrid-to-Gasoline Comparison 
 

Methodology.................................................................................................................. 36
 

References.................................................................................................................... 44
 

2
 
Chapter 1: Background on the Safe, Accountable, Flexible 

Efficient Transportation Equity Act: A Legacy for Users 

The Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for 

Users (SAFETEA-LU), also known as the 2005 Transportation Act, was enacted on 

August 10, 2005. SAFETEA-LU, which is codified at 23 United States Code (U.S.C.) 

166, concerns the Federal surface transportation programs for highways, highway 

safety, and transit for a 5-year period covering 2005-2009. Certain provisions of 23 

U.S.C. 166 addresses the High Occupancy Vehicle (HOV) facility programs that some 

states have in place. 

In general, for vehicles to operate in HOV facilities, they must have two or more 

occupants per vehicle. 23 U.S.C. 166 provides some exemptions to this occupancy 

requirement for “inherently low emitting” vehicles and other “low emission and energyefficient” vehicles. Thus, 23 U.S.C. 166 allows, but does not require, a new occupancy 

exemption for the use of “low emission and energy-efficient” vehicles that do not meet 

the minimum occupancy requirement in (HOV) facilities. States with existing HOV 

facilities may optionally adopt this exemption. If they choose to adopt the HOV 

occupancy exemption for low emission and energy-efficient vehicles, states must 

commit to update the eligibility and definition of low emission and energy-efficient 

vehicles to be consistent and comply with the methodology that we to present in the 

Final Rulemaking. Per 23 U.S.C. 166, the exemption for the use of low emission and 

energy-efficient vehicles in HOV facilities expires September 30, 2009. 

23 U.S.C. 166 directs EPA to provide a rulemaking establishing the criteria 

required to certify, or designate, a vehicle as a low emission and energy-efficient vehicle 

3
 
that may be eligible for use in HOV facilities. 23 U.S.C. 166 defines a low emission 

vehicle as one that is certified to EPA’s Tier 2 emissions standards. In the Preamble to 

the Notice of Proposed Rulemaking (NPRM), we propose to further refine the definition 

of a low emission vehicle as one that must comply with Tier 2 Bin 5 or better (Bins 5, 4, 

3, 2 and 1). 23 U.S.C. 166 defines an energy-efficient vehicle as one operating on an 

alternative fuel (as discussed in the Preamble to the NPRM), or one that is: 

 “...to have achieved not less than a 50-percent increase in 

city fuel economy or not less than a 25-percent increase in 

combined city/highway fuel economy...relative to a 

comparable vehicle that is an internal combustion gasoline 

fueled vehicle (other than a vehicle that has propulsion 

energy from onboard hybrid sources).”1 

23 U.S.C. 166 also directs EPA to establish guidelines and procedures for making the 

vehicle comparisons and performance calculations needed to determine an energyefficient vehicle. 

This Draft Technical Support Document describes the various vehicle 

comparison strategies which were considered for purposes of certifying an energyefficient vehicle based on the prescribed fuel economy percent increase. Ultimately, 

one comparison strategy is recommended to be codified through the Federal 

rulemaking process, and this comparison strategy is described in further detail in this 

document. 

Chapter 2: Discussion of Potential Vehicle Comparison 

Strategies 

1

 23 U.S.C. 166 (f)(3)(B)(i). 

4
 
As discussed in the previous section, 23 U.S.C. 166 defines an energy-efficient 

vehicle as one operating on an alternative fuel or one that achieves a 50-percent or 

better increase in city fuel economy or a 25-percent increase in combined city/highway 

fuel economy relative to a comparable gasoline-fueled vehicle, excluding hybrids, as a 

basis of comparison. This Draft Technical Support Document explains the process we 

used to 1) select a vehicle comparison strategy, 2) define what is considered to be a 

comparable gasoline-fueled vehicle, and 3) describe the guidelines and procedures 

needed to perform the calculations for comparing fuel economy values. 

23 U.S.C. 166 provided some guidance that indicates the desired outcome of 

EPA’s analyses (e.g., would not degrade HOV facilities, would provide incentives for 

purchase and use of hybrid and other energy efficient vehicles). 23 U.S.C. 166 also 

provided EPA with some guidance on a “comparable” vehicle, by referencing 49 U.S.C 

32908(b), Fuel Economy Labeling Requirements and Contents. Today's HOV proposal 

for making fuel economy comparisons and performance calculations is in accordance 

with 49 U.S.C 32908(b) because the fundamental fuel economy values that form the 

basis of comparison are obtained from the same tests as those used for fuel economy 

labeling purposes. The city fuel economy and combined city-highway fuel economy 

comparisons that are specified in 23 U.S.C. 166 are based on the same city and cityhighway fuel economy that is determined by EPA regulations in the Code of Federal 

Regulations (CFR) under 40 CFR Part 600. This assures that automobile 

manufacturers would not need to perform additional fuel economy tests for the purpose 

of determining if their vehicles would qualify for HOV facility exemptions. 

5
 
Furthermore, we determined three goals for a desirable fuel economy 

comparison methodology. First, the method should not result in a large number of 

vehicles qualifying for the exemption to prevent HOV lane degradation. Second, the 

method should be based on data and/or a method for analyzing data that is readily 

available to the public or to the state administering HOV facility requirements. Third, the 

vehicles that would qualify should be construed by a reasonable person as being truly 

"energy efficient" per the intent of Congress. We considered a variety of methods, and 

analyzed whether or not they met the above three goals. The following methods are 

discussed in detail below: 

1. Hybrid-to-Gasoline Vehicle Comparison 

2. Inertia Weight Class 

3. Hybrid-to-“Best in Class” Vehicle Comparison 

2.1 Hybrid-to-Gasoline Vehicle Comparison Method 

2.1.1 How does EPA propose to develop baseline fuel economy values for the 

hybrid-to-gasoline vehicle comparison methodology? 

In this method, hybrid vehicles would be compared to their gasoline namesake 

counterparts (e.g. the Ford Escape Hybrid would be compared to the Ford Escape 

gasoline model). 

 However, there are some hybrids that do not have similar gasoline counterparts 

(e.g. the Honda Insight and the Toyota Prius). For those vehicles, EPA is proposing that 

the comparison be based on gasoline vehicles within the same comparable class as 

used EPA’s annual Fuel Economy Guide, which is jointly published by EPA and DOE. 

The median unadjusted fuel economy of all the gasoline vehicles in that class would be 

determined, and then compared against the hybrid's fuel economy. This comparison 

6
 
would be done separately for each model year. For example, the Honda Insight is 

classified as a “two-seater”. For each model year, we would identify all of the “twoseater” gasoline vehicles and determine the median unadjusted city and unadjusted 

combined city-highway fuel economy values. These fuel economy values would form 

the baseline fuel economy values to be used for the Honda Insight comparison. 

As fuel economy can vary from year to year, these comparisons must be made 

separately for each model year. 

2.1.2. How is the comparison determined, based on a percent increase in vehicle 

fuel economy value? 

We are proposing the following process for making a fuel economy comparison 

using the hybrid-to-gasoline vehicle comparison methodology: 

1) Determine the list of all hybrid vehicles (separately for each model year) 

emission-certified by EPA prior to September 30, 2009. 

2) For hybrid vehicles with a similar gasoline counterpart, compare the 

unadjusted city and unadjusted combined city-highway fuel economy values to 

the similar gasoline counterpart. 

3) For hybrid vehicles with no similar gasoline counterpart, calculate the 

median unadjusted city and/or unadjusted combined city-highway fuel economy 

values for all gasoline vehicles in the same EPA comparable vehicle class and 

compare the hybrid vehicle fuel economy values to the median unadjusted city 

fuel economy value and the unadjusted city-highway value for the comparison 

gasoline vehicle. 

4) Evaluate the results according to the following criteria: 

7
 
	 If the candidate hybrid vehicle’s city fuel economy is 50 percent 

grater that the city fuel economy value of its gasoline counterpart 

then the vehicle would qualify as energy-efficient; 

	 If the candidate hybrid vehicle’s combined city-highway fuel 

economy is 25 percent greater than the combined city/fuel 

economy of its gasoline counter part, then the vehicle would qualify 

as energy-efficient; or 

	 Conversely, if the hybrid vehicles do not meet either of these 

required fuel economy thresholds relative to their gasoline 

counterparts, then the vehicle would not qualify as energy-efficient. 

Based on the low emission and energy-efficient vehicle criteria using the hybrid-togasoline vehicle comparison methodology described above, the potential lists of 

vehicles eligible for an HOV occupancy exemption are shown in Chapter 3 below. 

2.2 Inertia Weight Class Method 

2.2.1 Overview 

The inertia weight classes used in this methodology are taken from the 

Alternative Motor Vehicle Tax Credit portion of the Energy Policy Act of 2005 (2005 

Energy Act).2 The 2005 Energy Act specifies 14 of these classes, categorized 

separately for passenger cars and light trucks, as follows: 1500/1750, 2000, 2250, 

2500, 2750, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, and 7000/8500 lbs. In 

addition to being referred to in the 2005 Energy Act, these same inertia weight classes 

are also codified by EPA regulations at 40 CFR 86.129-94. EPA defines inertia weight 

2

 Energy Policy Act of 2005 [Public Law 109-58, August 8, 2005]. 

8
 
class as the class into which a vehicle is grouped for testing purposes based on its 

loaded vehicle weight (nominal empty vehicle weight plus 300 pounds (lbs.) used for 

cars and for light-duty trucks up through 6000 lbs. gross vehicle weight rating (GVWR)) 

or adjusted loaded vehicle weight (average of nominal empty weight and GVWR used 

for light-duty trucks greater than 6000 lbs. GVWR). 

The 2005 Energy Act also designates associated baseline "2002 model year" city 

fuel economy values, based on a sales-weighted harmonic average of the unadjusted 

city fuel economy for the vehicle type (car or truck) for the purposes of tax credit 

generation. We believe it would be appropriate to apply this same method for purposes 

of determining vehicles that would qualify for HOV exemptions, since the Transportation 

Act and 2005 Energy Act both intend to offer incentives to increase the sales and use 

of energy-efficient vehicles, including hybrid and diesel technologies.3 23 U.S.C. 166 

offers a commuting incentive, that is, the use of HOV facilities, for vehicles that do not 

meet the minimum occupancy requirement and the 2005 Energy Act offers a motor 

vehicle tax credit based on fuel economy, technology, and inertia weight. However, 

regardless of this consistent rationale, the inertia weight class methodology does not 

necessarily mean that a vehicle that is eligible for a tax credit would also eligible for an 

HOV occupancy exemption or vice versa. 

While the 2005 Energy Act provides baseline city fuel economy values, which we 

are proposing to adopt for the city fuel economy provision in 23 U.S.C. 166, 23 U.S.C. 

166 also provides criteria for a combined city/highway fuel economy. We developed the 

2002 baseline values for the combined city/highway fuel economy for each inertia 

weight class and vehicle type utilizing the same method - a sales-weighted harmonic 

3

 23 U.S.C. 166 (f)(5)(B)(c). 

9
 
average - as the baseline city fuel economy values. These values were then 

considered the baseline fuel economy values for a comparable gasoline vehicle. 

Inertia weight classes are also codified by EPA regulations at 40 CFR 86.129-94. 

Inertia weight class is the class into which a vehicle is grouped for testing purposes 

based on its loaded vehicle weight (nominal empty vehicle weight plus 300 lbs. used for 

cars and for light-duty trucks up through 6000 lbs. GVWR) or adjusted loaded vehicle 

weight (average of nominal empty weight and GVWR used for light-duty trucks greater 

than 6000 lbs. GVWR). 

It should be noted that while a vehicle would have the same inertia weight for the 

purposes of applying for tax credits and an HOV occupancy exemption, the same 

vehicle may not be eligible for both. Other factors that would influence a vehicle’s 

potential for a tax credit and an HOV occupancy exemption include: availability of tax 

credit based on an imposed cap of 60,000 vehicles per manufacturer; the vehicle’s 

emission certification; the availability of HOV facilities within a state; and the stringency 

of a State’s HOV occupancy exemption given that the statute allows states the option to 

make the fuel economy provisions codified by EPA more stringent. 

2.2.2 Baseline Fuel Economy 

The 2005 Energy Act designates baseline city fuel economy values in miles per 

gallon (mpg) separately for cars and trucks. These values are defined for each inertia 

weight class to which a vehicle’s fuel economy value is compared to determine eligibility 

for the tax credit. These baseline city fuel economy values are the sales-weighted 

harmonic averages of unadjusted city fuel economy for all model year 2002 vehicles 

within each inertia weight class. The use of an unadjusted fuel economy value, besides 

10
 
being the precedent set by the 2005 Energy Act as well as the Fuel Economy Trends 

Report, is important; the other option would be to utilize the adjusted fuel economy 

values, also known as the fuel economy label values. A Notice of Proposed 

Rulemaking4 was recently issued that proposes changes to the methodology for 

adjusting the fuel economy label values; the adjusted fuel economy label values are 

displayed on vehicles at the time of sale and used in the Fuel Economy Guide and 

Green Vehicle Guide. Thus, it is likely that the adjustment calculations would change 

during the period of the HOV exemption program. Therefore, a methodology based on 

an adjusted value would have to be recalculated. The unadjusted fuel economy values 

would remain unchanged by the proposed rulemaking and would be the preferable 

option as a basis of comparison for the purposes of this proposal. 

Since the baseline city fuel economy values are based on the 2002 model year in 

the 2005 Energy Act, these values are being proposed as the baseline for comparison 

for each model year until the end of the HOV exemption program on September 30, 

2009. We believe that it is technically sound to apply the 2002 model year as an 

ongoing baseline since the data are based on gasoline-only vehicles, which have 

maintained a nearly consistent fuel economy over the years. For example, as noted in 

the Executive Summary of the Fuel Economy Trends Report for 1975 through 2004 

model years: 

“Model year 2004 light-duty vehicles are estimated to 

average 20.8 miles per gallon (MPG). The MY2004 average 

is within the 20.6 to 20.9 mpg range that has occurred for the 

past eight years.”5 

4

 71 FR 5426, February 9, 2006. 

5

 Hellman, 2004. 

11
 
While the example given applies specifically to model year 2004 vehicles, it also notes 

that the average has not changed much in the past eight years except for light truck fuel 

economy, which has increased for two years. This increase is likely due, at least in part, 

to higher light-truck CAFE standards Overall, fuel economy has been influenced by 

marginal changes in gasoline technology prior to the introduction of hybrid technology; 

this time period includes the 2002 data and shows that this model year would be 

relevant as a point of comparison for subsequent model years. 

It is also preferable to use one model year as the ongoing baseline to avoid 

having to annually recalculate the baseline and to provide certainty for manufacturers, 

auto dealers, the public, and HOV administrators. Since the baseline is based on sales 

data, it is difficult to calculate a sales-weighted average early in a model year as data 

cannot be finalized until after the end of the model year. The benefits of an updated 

baseline are minimal since fuel economy has remained steady, and the administrative 

burden and loss of certainty are not worth minimal gains in accuracy. Finally, since the 

baseline fuel economy values are listed in the 2005 Energy Act as a basis of 

comparison, these numbers are considered codified and their use provides certainty 

with minimal loss of accuracy over the relatively short lifetime of the HOV exemption for 

energy-efficient vehicles. 

2.2.2.1 Baseline City Fuel Economy 

The baseline city fuel economy is generated from gasoline-only vehicles, 

excluding hybrids, from the 2002 model year. Thus the baseline city fuel economy 

values represent of a comparable gasoline vehicle within the same inertia weight class 

12
 
as the candidate vehicle being compared. The baseline city fuel economy values, as 

listed in the 2005 Energy Act, are in Table 2-1, below. 

13
 
Table 2-1: 2002 Baseline City Fuel Economy 

Inertia Weight 

(lbs.) 

Passenger 

Automobiles (mpg) 

Light Trucks 

(mpg) 

1500 or 1750 45.2 39.4 

2000 39.6 35.2 

2250 35.2 31.8 

2500 31.7 29.0 

2750 28.8 26.8 

3000 26.4 24.9 

3500 22.6 21.8 

4000 19.8 19.4 

4500 17.6 17.6 

5000 15.9 16.1 

5500 14.4 14.8 

6000 13.2 13.7 

6500 12.2 12.8 

7000 to 8500 11.3 12.1 

Reference: Energy Policy Act of 2005 (Public Law 109-58, August 8, 2005) 

2.2.2.2 Baseline Combined City/Highway Fuel Economy 

While 23 U.S.C. 166 prescribes fuel economy eligibility requirements based on 

the city and the combined city/highway fuel economy values, the 2005 Energy Act 

eligibility requirements for fuel economy are based solely on city fuel economy values. 

Today’s proposal, therefore, must designate baseline fuel economy values for both city 

and combined city/highway fuel economy values. As a result, we calculated the salesweighted harmonic average of the unadjusted combined city/highway fuel economy 

values for each inertia weight class separately for cars and trucks, again using the 2002 

model year as the baseline. 

Before performing the baseline fuel economy calculations for combined 

city/highway, we used the data set obtained for the 2002 model year to recalculate the 

city fuel economy baseline to ensure that the data and methodology for the proposal 

were consistent with the data and methodology used to calculate values presented in 

14
 
the 2005 Energy Act. The calculated values for city fuel economy were near matches to 

those of the 2005 Energy Act, and hence we deemed the calculations appropriate for 

the purposes of calculating the baseline combined city/highway fuel economy values. 

To perform the baseline calculations, we first separated the vehicles to remove 

any hybrids and any vehicles not fueled by gasoline, i.e., alternative fuels and diesel. 

Once we limited the vehicle population to conventional gasoline-fueled vehicles only, we 

further separated it into cars and trucks and then by inertia weight class, as listed below 

in Table 2-2. Finally, we calculated a sales-weighted harmonic average of the 

combined city/highway fuel economy for each inertia weight class within the data set 

using Equations 3-1 and 3-2, listed below. Equation 3-2 was used to calculate the 

sales-weighted harmonic average of fuel economy, mimicking how the baseline city fuel 

economy was determined. 

Table 2-2: Inertia Weight Classes 

Inertia Weight 

(lbs.) 

1500 or 1750 

2000 

2250 

2500 

2750 

3000 

3500 

4000 

4500 

5000 

5500 

6000 

6500 

7000 to 8500 

Equation 2-1. Combined (City/highway) Fuel Consumption 

15
 
1 Combined City/Highway Fuel Consumption = Unadjusted Combined Fuel Economy 

Equation 2-2. Combined (City/highway) Sales Weighted Fuel Economy 

∑Sales 

Sales - weighted Unadjusted Combined Fuel Economy =

∑(Sales×Combined Fuel Consumption)

For both cars and trucks, some inertia weight classes were not represented by 

the given data set, and thus the associated combined city/highway fuel economy values 

for the missing inertia weight classes had to be extrapolated. We extrapolated the 

combined city/highway fuel economy values by plotting the combined city/highway fuel 

economy values against their associated inertia weight class. Using spreadsheet 

software, we fit a curve to the data, shown in Figures 2-1 and 2-2, shown below, and 

determined Equations 2-3 and 2-4, shown below, from the curves. Based on Equations 

2-3 and 2-4, we calculated the combined city/highway values for all inertia weight 

classes to fit the curve. The resulting values for the baseline combined city/highway 

fuel economy are displayed in Table 2-3, shown below. 

16
 
car baseline cmb 

y = 15339x-0.7711 

40.0 

35.0 

30.0 

25.0 

20.0 

15.0 

10.0 

5.0 

0.0 

0 1000 2000 3000 4000 5000 6000 7000 

inertia wt 

Figure 2-1. Determination of Baseline Combined Fuel Economy Values for Cars 

truck baseline cmb 

y = 14768x-0.7807 

cm

b FE 

35.0 

30.0 

25.0 

Figure 2-2. Determination of Baseline Combined Fuel Economy Values for Trucks 

Equation 2-3. Baseline Combined City/Highway Fuel Economy for Light-Duty 

Vehicles 

cm

b FE 

20.0 

15.0 

10.0 

5.0 

0.0 

0 1000 2000 3000 4000 5000 6000 7000 

inertia wt 

− Baseline Combined Fuel Economy = 15339 × (Inertia Weight Class 0.7711 )

Equation 2-4. Baseline Combined City/highway Fuel Economy for Light-Duty 

Trucks 

17 
− Baseline Combined Fuel Economy = 14768× (Inertia Weight Class 0.7807 )

18
 
Table 2-3: 2002 Baseline Combined City/highway Fuel Economy 

Inertia Weight 

(lbs.) 

Passenger 

Automobiles (mpg) 

Light Trucks 

(mpg) 

1500 or 1750 48.4 43.4 

2000 43.7 39.1 

2250 39.9 35.7 

2500 36.8 32.9 

2750 34.2 30.5 

3000 32.0 28.5 

3500 28.4 25.3 

4000 25.6 22.8 

4500 23.4 20.8 

5000 21.6 19.1 

5500 20.0 17.8 

6000 18.7 16.6 

6500 17.6 15.6 

7000 to 8500 16.6 14.7 

2.2.3 Vehicle Comparison Strategy for Inertia Weight 

Using the pre-defined inertia weight classes and baseline city fuel economy 

values from the 2005 Energy Act and the extrapolated baseline combined city/highway 

fuel economy values, fuel economy comparisons can be made to evaluate whether a 

candidate vehicle meets the established fuel economy percent increase criteria, 50-

percent or better increase in city fuel economy or 25-percent or better increase in 

combined city/highway fuel economy. 

We used Equation 2-4, shown below to calculate the percent increase in 

unadjusted fuel economy for all vehicles, according to their vehicle type, inertia weight 

class, and the associated baseline city and combined city/highway fuel economy values. 

Equation 2-4: Percent Increase 

19
 
(Unadjusted FE − 2002 Baseline FE) Percent Increase = ×100 

2002 Baseline FE 

*FE = fuel economy 

After calculating the percent increase for the unadjusted city and unadjusted combined 

city/highway fuel economy values for each vehicle within its associated inertia weight 

class, we applied the following criteria: 

1. If the percent increase for unadjusted city fuel economy was 50 percent or 

better, at a minimum, then the vehicle would qualify as energy-efficient; or 

2. If the percent increase for unadjusted combined city/highway fuel economy 

was 25 percent or better, at a minimum, then the vehicle would qualify as 

energy-efficient; or 

3. If the percent increase for unadjusted city fuel economy was less than 50 

percent and the percent increase for unadjusted combined city/highway fuel 

economy is less than 25 percent, then the vehicle would not qualify as 

energy-efficient. 

Thus, all vehicles meeting Criteria 1 and 2 would be classified as “energyefficient.” The minimum thresholds to qualify in miles per gallon are presented in Tables 

2-4 and 2-5, shown below for the unadjusted city and unadjusted combine city/highway 

fuel economy values. It should be noted that to be eligible for an HOV exemption, a 

vehicle would have to meet the criteria for both energy-efficient and low emission, and 

low emission vehicles are being proposed as those meeting the Federal Tier 2 Bin 5 or 

cleaner (i.e. Bins 5, 4, 3, 2, and 1) emission standards, or comparable California Low 

Emission Vehicle-II (LEV-II) emission standards that are as or more stringent (i.e. LEVII, ULEV-II, SULEV-II, PZEV, and ZEV for passenger cars - light-duty vehicles and light20
 
duty trucks, including most sport utility vehicles and most large pickup trucks - up to 

8500 lbs. GVWR). 

Table 2-4. EPA Minimum Eligibility Thresholds for Unadjusted City Fuel Economy 

Inertia Weight 

(lbs.) 

Passenger 

Automobiles (mpg) 

Light Trucks 

(mpg) 

1500 or 1750 67.8 59.1 

2000 59.4 52.8 

2250 52.8 47.7 

2500 47.6 43.5 

2750 43.2 40.2 

3000 39.6 37.4 

3500 33.9 32.7 

4000 29.7 29.1 

4500 26.4 26.4 

5000 23.9 24.2 

5500 21.6 22.2 

6000 19.8 20.6 

6500 18.3 19.2 

7000 to 8500 17.0 18.2 

Table 2-5. EPA Minimum Eligibility Thresholds for Unadjusted Combined 
 

City/Highway Fuel Economy
 

Inertia Weight 

(lbs.) 

Passenger 

Automobiles (mpg) 

Light Trucks 

(mpg) 

1500 or 1750 60.5 54.2 

2000 54.6 48.9 

2250 49.9 44.6 

2500 46.0 41.1 

2750 42.7 38.1 

3000 39.9 35.6 

3500 35.5 31.6 

4000 32.0 28.5 

4500 29.2 26.0 

5000 26.9 23.9 

5500 25.0 22.2 

6000 23.4 20.7 

6500 22.0 19.5 

7000 to 8500 20.8 18.4 

21
 
In addition to the criteria described above, we believe that an additional criterion 

is necessary to determine if a vehicle is fuel efficient. The proposed inertia weight class 

method, or any of the other methods considered, result in lists of potentially qualifying 

vehicles that include a few models that fail to achieve the level of the Corporate 

Average Fuel Economy standard. Thus we are proposing an additional comparison 

criterion, to be used as a "floor" to prevent the inclusion of vehicles which may be fuel 

efficient relative to others in the same inertia weight class. In order for a vehicle to 

qualify as fuel efficient, it must also have a combined fuel economy that is higher than 

25 percent above the applicable CAFE car or truck standard (Table 2-6). We believe 

that this additional criterion is in keeping with the Transportation Act requirement that 

the combined fuel economy be 25 percent better than a comparable gasoline vehicle. 

Table 2-6. CAFE Standards for Cars and Trucks 

CAFE 

Standard 

25 percent 

of the CAFE 

Standard 

All cars 27.5 mpg 34.4 mpg 

2005 trucks 21.0 mpg 26.3 mpg 

2006 trucks 21.6 mpg 27.0 mpg 

2007 trucks 22.2 mpg 27.8 mpg 

2008 trucks 22.5 mpg 28.1 mpg 

22
 
2.2.4. List of Eligible Vehicles Using Inertia Weight Methodology 

The vehicles that would be eligible for HOV exemption using the inertial weight 

methodology are shown in Tables 2.7 and 2.8 below. 

Table 2.7. List of Eligible Federally Certified Low Emission and Energy-Efficient 

Vehicles Generated Using the Inertia Weight Methodology 

MY Mfr Vehicle 

Model 

Engine 

Family 

Tran Int Wgt 

(lbs) 

Tier 2 

Std 

Unadj 

City FE 

(mpg) 

City FE 

Inc Over 

Baseline (%) 

Unadj 

Cmb FE 

(mpg) 

Cmb FE 

Inc Over 

Base-line 

(%) 

CARS 

2003 Honda Civic Hybrid 3HNXV0 

1.36CV AV 3000 B5 52.6 99 56.0 75 

2003 Honda Civic Hybrid 3HNXV0 

1.36CV M5 3000 B5 50.0 89 55.7 74 

2003 Honda Insight 3HNXV0 

1.0PCE AV 2250 B5 62.8 78 66.4 66 

2004 Honda Civic Hybrid 4HNXV0 

1.37CP AV 3000 B5 52.6 99 56.0 75 

2004 Honda Civic Hybrid 4HNXV0 

1.37CP M5 3000 B5 50.0 89 55.7 74 

2004 Honda Insight 4HNXV0 

1.0NCE AV 2250 B5 62.8 78 66.4 66 

2004 Toyota Prius 4TYXV0 

1.5MC1 AV 3000 B3 66.6 152 65.8 106 

2005 Honda Accord Hybrid 5HNXV0 

3.01B4 L5 3500 B5 32.2 42 37.5 32 

2005 Honda Civic Hybrid 5HNXV0 

1.3YCV AV 3000 B2 52.6 99 56.0 75 

2005 Honda Civic Hybrid 5HNXV0 

1.3YCV M5 3000 B2 50.0 89 55.7 74 

2005 Honda Insight 5HNXV0 

1.0XCE AV 2250 B5 62.8 78 66.4 66 

2005 Toyota Prius 5TYXV0 

1.5MC1 AV 3000 B3 66.6 152 65.8 106% 

2006 Honda Civic Hybrid 6HNXV0 

1.3XCP AV 3000 B2 54.6 107 58.8 84 

2006 Honda Insight 6HNXV0 

1.0VK5 AV 2250 B5 62.8 78 66.4 66 

2006 Toyota Prius 6TYXV0 

1.5MC1 AV 3000 B3 66.6 152 65.8 106 

23
 
2007 Honda Accord 

Hybrid 

7HNXV0 

3.0ZMC L5 4000 B2 31.3 58 36.3 42 

2007 Honda Civic 

Hybrid 

7HNXV0 

1.3JCP AV 3000 B2 54.6 107 58.8 84 

2007 Toyota Camry 

Hybrid 

7TYXV0 

2.4HC1 AV 4000 B3 44.2 123 45.9 79 

2007 Toyota Prius 7TYXV0 

1.5HC1 AV 3000 B3 66.6 152 65.8 106 

TRUCKS 

2005 Ford Escape Hybrid 

2WD 

5FMXT0 

2.31EE AV 4000 B4 39.6 104 39.5 74 

2005 Ford Escape Hybrid 

4WD 

5FMXT0 

2.31EE AV 4000 B4 36.6 89 36.7 61 

2005 Honda Odyssey 2WD 5HNXT0 

3.5AB4 L5 4500 B5 21.7 23 26.4 27 

2006 Ford Escape Hybrid 

4WD 

6FMXT0 

2.32EE AV 4000 B4 36.6 89 36.7 61 

2006 Ford Escape Hybrid 

FWD 

6FMXT0 

2.32EE AV 4000 B4 39.6 104 39.5 74 

2006 Lexus RX 400H 

2WD 

6TYXT03 

.3CC1 AV 4500 B3 36.8 109 36.2 74 

2006 Lexus RX 400H 

4WD 

6TYXT03 

.3CC1 AV 4500 B3 34.3 95 34.3 65 

2006 Lexus Tribute Hybrid 

4WD 

6FMXT0 

2.32EE AV 4000 B4 36.6 89 36.7 61 

2006 Mercury 

Mariner 

Hybrid 4WD 

6FMXT0 

2.32EE AV 4000 B4 36.6 89 36.7 61 

2006 Toyota Highlander 

Hybrid 2WD 

6TYXT03 

.3CC1 AV 4500 B3 36.8 109 36.2 74 

2006 Toyota Highlander 

Hybrid 4WD 

6TYXT03 

.3CC1 AV 4500 B3 34.3 95 34.3 65 

2006 Toyota RAV4 2WD 6TYXT03 

.5PEM L5 4000 B5 24.4 26 28.9 27 

2006 Toyota RAV4 4WD 6TYXT02 

.4PEM L4 4000 B5 25.5 31 29.2 28 

2007 Ford Escape 

Hybrid 2WD 

7FMXT0 

2.32ZE AV 4000 B3 35.8 85 36.5 60 

2007 Ford Escape 

Hybrid FWD 

7FMXT0 

2.32ZE AV 4000 B3 41.1 112 40.6 78 

24
 
2007 Honda CR-V 4WD 7HNXT0 

2.4FKR 

L5 4000 B5 24.5 27 28.5 25 

2007 Lexus RX 400H 

2WD 

7TYXT03 

.3CC1 

AV 4500 B3 35.7 103 35.0 69 

2007 Lexus RX 400H 

4WD 

7TYXT03 

.3CC1 

AV 4500 B3 34.3 9585 34.3 65 

2007 Mercury Mariner 

Hybrid 4WD 

7FMXT0 

2.32ZE 

AV 4000 B3 35.8 85 36.5 60 

2007 Saturn Vue 

 Hybrid 

7GMXT0 

2.4130 

L4 3500 B5 29.8 37 34.0 35 

2007 Toyota Highlander 

Hybrid 2WD 

7TYXT03 

.3CC1 

AV 4500 B3 35.7 103 35.0 69 

2007 Toyota Highlander 

Hybrid 4WD 

7TYXT03 

.3CC1 

AV 4500 B3 34.3 95 35.3 65 

2007 Toyota RAV4 2WD 7TYXT03 

.5BEM 

L5 4000 B5 24.4 26 28.9 27 

2007 Toyota RAV4 4WD 7TYXT02 

.4BEM 

L4 4000 B5 25.3 31 29.0 27 

2007 Toyota Tacoma 2WD 7TYXT02 

.7AEM 

M5 4000 B5 25.8 33 29.4 29 

DEDICATED ALTERNATIVE FUEL (CNG) VEHICLES 

2003 Honda Civic - CNG 3HNXV0 

1.73W3 N/A B2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2004 Honda Civic – CNG 4HNXV0 

1.74W0 N/A B2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2005 Honda Civic - CNG 5HNXV0 

1.7BF3 N/A B2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2003 Ford Crown Victoria 

- CNG 

3FMXV0 

4.6VP5 N/A B3 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2004 Ford Crown Victoria 

- CNG 

4FMXV0 

4.6VP5 N/A B3 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

Unless noted as a dedicated alternative fuel vehicle, all of the listed vehicles operate on gasoline, and some may also be flexible-fuel vehicles. 

MY = Model Year 

Mfr = Manufacturer 

Tran = Transmission type 

Int Wgt = Inertia Weight Class 

Std = Standard 

Unadj = Unadjusted 

FE = Fuel Economy 

Inc = Increase 

Cmb = Combined city-highway 

B = Bin 

25
 
Table 2.8 List of Eligible California Certified Low Emission and Energy-Efficient 

Vehicles Generated Using the Inertia Weight Methodology 

MY Mfr Vehicle 

Model 

Engine 

Family 

Tran Int Wgt 

(lbs) 

LEV- II 

Std 

Unadj 

City FE 

(mpg) 

City FE 

Inc Over 

Baseline 

(%) 

Unadj 

Cmb FE 

(mpg) 

Cmb FE 

Inc Over 

Baseline (%) 

CARS 

2003 Honda Civic Hybrid 3HNXV0 

1.36CV AV 3000 S2 52.6 99 56.0 75 

2003 Honda Civic Hybrid 3HNXV0 

1.36CV M5 3000 S2 50.0 89 55.7 74 

2003 Honda Insight 3HNXV0 

1.0PCE AV 2250 S2 62.8 78 66.4 66 

2004 Honda Civic Hybrid 4HNXV0 

1.37CP AV 3000 S2 52.6 99 56.0 75 

2004 Honda Civic Hybrid 4HNXV0 

1.37CP M5 3000 S2 50.0 89 55.7 74 

2004 Honda Insight 4HNXV0 

1.0NCE AV 2250 S2 62.8 78 66.4 66 

2004 Toyota Prius 4TYXV01 

.5MC1 AV 3000 S2 66.6 152 65.8 106 

2005 Honda Accord Hybrid 5HNXV0 

3.01B4 L5 3500 U2 32.2 42 37.5 32 

2005 Honda Civic Hybrid 5HNXV0 

1.3YCV AV 3000 S2 52.6 99 56.0 75 

2005 Honda Civic Hybrid 5HNXV0 

1.3YCV M5 3000 S2 50.0 89 55.7 74 

2005 Honda Insight 5HNXV0 

1.0XCE AV 2250 S2 62.8 78 66.4 66 

2005 Toyota Prius 5TYXV01 

.5MC1 AV 3000 S2 66.6 152 65.8 106 

2006 Honda Civic Hybrid 6HNXV0 

1.3XCP AV 3000 S2 54.6 107 58.8 84 

2006 Honda Insight 6HNXV0 

1.0VK5 AV 2250 S2 62.8 78 66.4 66 

2006 Toyota Prius 6TYXV01 

.5MC1 AV 3000 S2 66.6 152 65.8 106 

2007 Honda Accord Hybrid 7HNXV0 

3.0ZMC L5 4000 S2 31.3 58 36.3 42 

2007 Honda Civic Hybrid 7HNXV0 

1.3JCP AV 3000 S2 54.6 107 58.8 84 

2007 Toyota Camry Hybrid 7TYXV02 

.4HC1 AV 4000 S2 44.2 123 45.9 79 

2007 Toyota Prius 7TYXV01 

.5HC1 AV 3000 S2 66.6 152 65.8 106 

26
 
MY Mfr Vehicle 

Model 

Engine 

Family 

Tran Int Wgt 

(lbs) 

LEV- II 

Std 

Unadj 

City FE 

(mpg) 

City FE 

Inc Over 

Baseline 

(%) 

Unadj 

Cmb FE 

(mpg) 

Cmb FE 

Inc Over 

Baseline (%) 

TRUCKS 

2005 Ford Escape 

Hybrid 2WD 

5FMXT0 

2.31EE AV 4000 S2 39.6 104 39.5 74 

2005 Ford Escape 

Hybrid 4WD 

5FMXT0 

2.31EE AV 4000 S2 36.6 89 36.7 61 

2005 Honda Odyssey 2WD 5HNXT0 

3.5AB4 L5 4500 U2 21.7 23 26.4 27 

2006 Ford Escape 

Hybrid 4WD 

6FMXT0 

2.32EE AV 4000 S2 36.6 89 36.7 61 

2006 Ford Escape 

Hybrid FWD 

6FMXT0 

2.32EE AV 4000 S2 39.6 104 39.5 74 

2006 Lexus RX 400H 

2WD 

6TYXT03 

.3CC1 AV 4500 S2 36.8 109 36.2 74 

2006 Lexus RX 400H 

4WD 

6TYXT03 

.3CC1 AV 4500 S2 34.3 95 34.3 65 

2006 Mazda Tribute Hybrid 

4WD 

6FMXT0 

2.32EE AV 4000 S2 36.6 89 36.7 61 

2006 Mercury 

Mariner 

Hybrid 4WD 

6FMXT0 

2.32EE AV 4000 S2 36.6 89 36.7 61 

2006 Toyota Highlander 

Hybrid 2WD 

6TYXT03 

.3CC1 AV 4500 S2 36.8 109 36.2 74 

2006 Toyota Highlander 

Hybrid 4WD 

6TYXT03 

.3CC1 AV 4500 S2 34.3 95 34.3 65 

2006 Toyota RAV4 2WD 6TYXT03 

.5PEM L5 4000 U2 24.4 26 28.9 27 

2006 Toyota RAV4 4WD 6TYXT02 

.4PEM L4 4000 U2 25.5 31 29.2 28 

2007 Ford Escape 

Hybrid 7FMXT0 

2.32ZE 

AV 4000 S2 35.8 85 36.5 60 

2007 Ford Escape 

Hybrid 7FMXT0 

2.32ZE 

AV 4000 S2 41.1 112 40.6 78 

2007 Honda CR-V 4WD 7HNXT0 

2.4FKR 

L5 4000 U2 24.5 27 28.5 25 

27
 
MY Mfr Vehicle 

Model 

Engine 

Family 

Tran Int Wgt 

(lbs) 

LEV- II 

Std 

Unadj 

City FE 

(mpg) 

City FE 

Inc Over 

Baseline 

(%) 

Unadj 

Cmb FE 

(mpg) 

Cmb FE 

Inc Over 

Baseline (%) 

2007 Lexus RX 400H 

2WD 7TYXT03 

.3CC1 

AV 4500 S2 35.7 103 35 69 

2007 Lexus RX 400H 

4WD 7TYXT03 

.3CC1 

AV 4500 S2 34.3 95 34.3 65 

2007 Mercury 

Mariner 

Hybrid 

7FMXT0 

2.32ZE AV 4000 S2 35.8 85 36.5 60 

2007 Saturn Vue Hybrid 7GMXT0 

2.4130 

L4 3500 L2 29.8 37 34.0 35 

2007 Toyota Highlander 

Hybrid 2WD 7TYXT03 

.3CC1 

AV 4500 S2 35.7 103 35 69 

2007 Toyota Highlander 

Hybrid 4WD 7TYXT03 

.3CC1 

AV 4500 S2 34.3 95 34.3 65 

2007 Toyota RAV4 2WD 7TYXT03 

.5BEM L5 4000 U2 24.4 26 28.9 27 

2007 Toyota RAV4 4WD 7TYXT02 

.4BEM L4 4000 U2 25.3 31 29 27 

2007 Toyota Tacoma 2WD 7TYXT02 

.7AEM 

M5 4000 M2 25.8 33 29.4 29 

DEDICATED ALTERNATIVE FUEL (CNG) VEHICLES 

2004 Honda Civic – CNG 4HNXV0 

1.74W2 N/A S2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2005 Honda Civic - CNG 5HNXV0 

1.7BF4 N/A S2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

Unless noted as a dedicated alternative fuel vehicle, all of the listed vehicles operate on gasoline, and some may also be flexible-fuel 

vehicles. 

MY = Model Year 

Mfr = Manufacturer 

Tran = Transmission 

Int Wgt = Inertia Weight Class 

Std = Standard 

Unadj = Unadjusted 

FE = Fuel Economy 

Inc = Increase 

Cmb = Combined city-highway 

S2 = SULEVII 

U2 = ULEVII 

2.3 Hybrid-to-“Best in Class” Method 

EPA also considered defining a “comparable vehicle” as the vehicle with the best 

fuel economy of a particular class of vehicles as defined by EPA’s annual Fuel 

Economy Guide, which is jointly published by EPA and DOE. This approach is not a fuel 

28
 
and technology neutral approach, meaning that it only considers hybrid vehicles. No 

gasoline, diesel, or flexible-fuel would be considered for an HOV facilities exemption 

using this methodology. 

 For the “best in class” methodology, the following process would be used for 

making a fuel economy comparison: 

1) Sort the list of all hybrid vehicles (all model years certified for sale prior 

to September 30, 2009) by the vehicle classes defined in EPA’s annual Fuel 

Economy Guide for each model year. The vehicle classes are defined in the Fuel 

Economy Guide as follows: Two-seater, Minicompact Vehicle, Subcompact 

Vehicle, Compact Vehicle, Midsize Vehicle, Large Vehicle, Small Station 

Wagon, Midsize Station Wagon, Large Station Wagon, Small Pickup Truck, 

Standard Pickup Truck, Passenger Van, Cargo Van, Minivan, Sport Utility 

Vehicle (SUV), and Special Purpose Vehicle. 

2) For each model year and each vehicle class, determine which gasoline 

vehicle has the highest unadjusted city and unadjusted city-highway combined 

fuel economy values. For example, for the 2006 model year, the compact 

vehicle with the highest unadjusted city and unadjusted combined city-highway 

fuel economy values is the Toyota Corolla. The Toyota Corolla would be the 

comparison vehicle for any 2006 hybrid vehicle that is classified as a compact 

car. In this case, the 2006 Honda Civic hybrid is the only hybrid classified as a 

compact car. See Table 2.8 below for a complete list of comparison vehicles. 

Table 2.8 Vehicles with highest unadjusted city fuel economy values and 

unadjusted combined city-highway fuel economy vehicles by Fuel Economy 

Guide Class 

Model Hybrid Comparison Gasoline Fuel Economy 

29
 
Year Make/Model Make/Model Guide Class 

2003 Honda Insight Toyota MR2 Two-seater 

2003 Honda Civic Hybrid Honda Civic Compact 

2004 Honda Insight Toyota MR2 Two-seater 

2004 Honda Civic Hybrid Honda Civic Compact 

2004 Toyota Prius Hyundai Elantra Midsize 

2005 Honda Insight Toyota MR2 Two-seater 

2005 Honda Civic Hybrid Honda Civic Compact 

2005 Toyota Prius Hyundai Elantra Midsize 

2005 Honda Accord Hybrid Hyundai Elantra Midsize 

2005 Ford Escape Hybrid 2WD Toyota RAV4 2WD SUV 

2005 Ford Escape Hybrid 4WD Toyota RAV4 2WD SUV 

2006 Honda Insight Mazda MX-5 Two-seater 

2006 Honda Civic Hybrid Toyota Corolla Compact 

2006 Toyota Prius Hyundai Elantra Midsize 

2006 Honda Accord Hybrid Hyundai Elantra Midsize 

2006 Ford Escape Hybrid FWD Toyota RAV4 2WD SUV 

2006 Ford Escape Hybrid 4WD Toyota RAV4 2WD SUV 

2006 Lexus RX 400H 2WD Toyota RAV4 2WD SUV 

2006 Lexus RX 400H 2WD Toyota RAV4 2WD SUV 

2006 Mazda Tribute Hybrid Toyota RAV4 2WD SUV 

2006 Mercury Mariner Hybrid Toyota RAV4 2WD SUV 

2006 Toyota Highlander Hybrid 2WD Toyota RAV4 2WD SUV 

2006 Toyota Highlander Hybrid 2WD Toyota RAV4 2WD SUV 

2007 Honda Insight Toyota Corolla Compact 

2007 Honda Civic Hybrid Toyota Corolla Compact 

2007 Lexus GS 450H Toyota Corolla Compact 

2007 Toyota Prius Nissan Versa Midsize 

2007 Honda Accord Hybrid Jeep Patriot 4WD SUV 

2007 Ford Escape Hybrid FWD Jeep Patriot 4WD SUV 

2007 Ford Escape Hybrid 4WD Jeep Patriot 4WD SUV 

2007 Lexus RX 400H 2WD Jeep Patriot 4WD SUV 

2007 Lexus RX 400H 2WD Jeep Patriot 4WD SUV 

2007 Mercury Mariner Hybrid Jeep Patriot 4WD SUV 

2007 Toyota Highlander Hybrid 2WD Jeep Patriot 4WD SUV 

2007 Toyota Highlander Hybrid 2WD Jeep Patriot 4WD SUV 

3) Compare the hybrid vehicle fuel unadjusted economy values to the 

unadjusted city fuel economy value and the unadjusted city-highway fuel 

economy value for the comparison gasoline vehicle. 

4) Evaluate the results according to the following criteria: 

	 If the percent increase for city fuel economy is greater than 50 

percent over the baseline city fuel economy for the given specific 

vehicle, then the vehicle would qualify as energy-efficient; 

30
 
	 If the percent increase for combined city-highway fuel economy is 

greater than 25 percent over the baseline combined city-highway 

fuel economy for the given specific vehicle, then the vehicle would 

qualify as energy-efficient; or 

	 Conversely, if the candidate vehicle’s fuel economy does not meet 

these required thresholds when compared to the baseline fuel 

economy for that class of vehicle, then the vehicle would not qualify 

as energy-efficient. 

The vehicles that would be eligible for HOV exemption using the inertial weight 

methodology are shown in Tables 2.9 and 2.10 below. 

31
 
Table 2.9. List of Eligible Federally Certified Low Emission and Energy-Efficient 

Vehicles Generated Using the Hybrid-to-“Best in Class” Methodology 

MY Mfr Vehicle 

Model 

Engine 

Family 

Tran 

Fuel 

Economy 

Guide 

Class 

Tier 2 

Std 

Unadj 

City FE 

(mpg) 

City FE 

Inc Over 

Baseline (%) 

Unadj 

Cmb FE 

(mpg) 

Cmb FE 

Inc Over 

Base-line 

(%) 

CARS 

2003 Honda Insight 3HNXV0 

1.0PCE AV Two-seater B5 62.8 132 66.4 124 

2004 Honda Insight 4HNXV0 

1.0NCE AV Two-seater B5 62.8 131 66.4 120 

2004 Toyota Prius 4TYXV0 

1.5MC1 AV Midsize B3 66.6 121 65.8 87 

2005 Honda Insight 5HNXV0 

1.0XCE AV Two-seater B5 62.8 116 66.4 98 

2005 Toyota Prius 5TYXV0 

1.5MC1 AV Midsize B3 66.6 124 65.8 90 

2006 Honda Civic Hybrid 6HNXV0 

1.3XCP AV Compact B2 54.6 53 58.8 41 

2006 Honda Insight 6HNXV0 

1.0VK5 AV Two-seater B5 62.8 129 66.4 112 

2006 Toyota Prius 6TYXV0 

1.5MC1 AV Midsize B3 66.6 124 65.8 90 

2007 Honda Civic Hybrid 

7HNXV0 

1.3JCP AV Compact B2 54.6 53 58.8 41 

2007 Toyota Prius 7TYXV0 

1.5HC1 AV Midsize B3 66.6 101 65.8 76 

TRUCKS 

2005 Ford Escape Hybrid 

2WD 

5FMXT0 

2.31EE AV SUV B4 39.6 46 39.5 28 

2006 Ford Escape Hybrid 

FWD 

6FMXT0 

2.32EE AV SUV B4 39.6 48 39.5 28 

2007 Ford Escape Hybrid 

FWD 

7FMXT0 

2.32ZE AV SUV B3 41.1 46 40.6 29 

DEDICATED ALTERNATIVE FUEL (CNG) VEHICLES 

2003 Honda Civic - CNG 3HNXV0 

1.73W3 N/A B2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2004 Honda Civic – CNG 4HNXV0 

1.74W0 N/A B2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2005 Honda Civic - CNG 5HNXV0 

1.7BF3 N/A B2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2003 Ford Crown Victoria 

- CNG 

3FMXV0 

4.6VP5 N/A B3 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2004 Ford Crown Victoria 

- CNG 

4FMXV0 

4.6VP5 N/A B3 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

32
 
Unless noted as a dedicated alternative fuel vehicle, all of the listed vehicles operate on gasoline, and some may also be flexible-fuel vehicles. 

MY = Model Year 

Mfr = Manufacturer 

Tran = Transmission type 

Std = Standard 

Unadj = Unadjusted 

FE = Fuel Economy 

Inc = Increase 

Cmb = Combined city-highway 

B = Bin 

33
 
Table 2.10 List of Eligible California-Certified Low Emission and Energy-Efficient 

Vehicles Generated Using the Hybrid-to-“Best in Class” Methodology 

MY Mfr Vehicle 

Model 

Engine 

Family 

Tran 

Fuel 

Economy 

Guide Class 

LEV- II 

Std 

Unadj 

City FE 

(mpg) 

City FE 

Inc Over 

Baseline 

(%) 

Unadj 

Cmb FE 

(mpg) 

Cmb FE 

Inc Over 

Baseline (%) 

CARS 

2003 Honda Civic Hybrid 3HNXV01 

.36CV AV Compact S2 52.6 52 56.0 45 

2003 Honda Civic Hybrid 3HNXV01 

.36CV M5 Compact S2 50.0 59 55.7 46 

2003 Honda Insight 3HNXV01 

.0PCE AV Two-seater S2 62.8 249 66.4 201 

2004 Honda Civic Hybrid 4HNXV01 

.37CP AV Compact S2 52.6 50 56.0 41 

2004 Honda Civic Hybrid 4HNXV01 

.37CP M5 Compact S2 50.0 42 55.7 40 

2004 Honda Insight 4HNXV01 

.0NCE AV Two-seater S2 62.8 214 66.4 177 

2004 Toyota Prius 4TYXV01. 

5MC1 AV Midsize S2 66.6 200 65.8 139 

2005 Honda Civic Hybrid 5HNXV01 

.3YCV AV Midsize S2 52.6 50 56.0 41 

2005 Honda Civic Hybrid 5HNXV01 

.3YCV M5 Compact S2 50.0 42 55.7 40 

2005 Honda Insight 5HNXV01 

.0XCE AV Compact S2 62.8 224 66.4 185 

2005 Honda Accord 

Hybrid 

5HNXV03 

.01B4 L5 Midsize S2 32.2 37 37.48 32 

2005 Toyota Prius 5TYXV01. 

5MC1 AV Two-seater S2 66.6 201 65.8 140 

2006 Honda Civic Hybrid 6HNXV01 

.3XCP AV Midsize S2 54.6 62 58.8 51 

2006 Honda Insight 6HNXV01 

.0VK5 AV Compact S2 62.8 211 66.4 173 

2006 Toyota Prius 6TYXV01. 

5MC1 AV Two-seater S2 66.6 200 65.8 144 

2007 Honda Accord 

Hybrid 

7HNXV03 

.0ZMC L5 Midsize S2 31.3 37 36.3 31 

2007 Honda Civic Hybrid 7HNXV01 

.3JCP AV Midsize S2 54.6 67 58.8 51 

2007 Toyota Camry Hybrid 7TYXV02. 

4HC1 AV Midsize S2 44.2 66 45.9 44 

34
 
MY Mfr Vehicle 

Model 

Engine 

Family 

Tran 

Fuel 

Economy 

Guide Class 

LEV- II 

Std 

Unadj 

City FE 

(mpg) 

City FE 

Inc Over 

Baseline 

(%) 

Unadj 

Cmb FE 

(mpg) 

Cmb FE 

Inc Over 

Baseline (%) 

2007 Toyota Prius 7TYXV01. 

5HC1 AV Midsize S2 66.6 210 65.8 154 

TRUCKS 

2005 Ford Escape 

Hybrid 2WD 

5FMXT02. 

31EE AV 4000 S2 39.6 65 39.5 46 

2005 Ford Escape 

Hybrid 4WD 

5FMXT02. 

31EE AV 4000 S2 36.6 78 36.7 57 

2006 Ford Escape 

Hybrid 4WD 

6FMXT02. 

32EE AV SUV S2 36.6 59 36.7 41 

2006 Ford Escape 

Hybrid FWD 

6FMXT02. 

32EE AV SUV S2 39.6 59 39.5 42 

2006 Lexus RX 400H 

2WD 

6TYXT03. 

3CC1 AV SUV S2 36.8 141 36.2 96 

2006 Lexus RX 400H 

4WD 

6TYXT03. 

3CC1 AV SUV S2 34.3 124 34.3 86 

2006 Mazda Tribute 

Hybrid 4WD 

6FMXT02. 

32EE AV SUV S2 36.6 59 36.7 41 

2006 Mercury 

Mariner 

Hybrid 4WD 

6FMXT02. 

32EE AV SUV S2 36.6 75 36.7 53 

2006 Toyota Highlander 

Hybrid 2WD 

6TYXT03. 

3CC1 AV SUV S2 36.8 72 36.2 45 

2006 Toyota Highlander 

Hybrid 4WD 

6TYXT03. 

3CC1 AV SUV S2 34.3 67 34.3 42 

2007 Ford Escape 

Hybrid 4WD 7FMXT02. 

32ZE 

AV SUV S2 35.8 55 36.5 39 

2007 Ford Escape 

Hybrid FWD 7FMXT02. 

32ZE 

AV SUV S2 41.1 64 40.6 45 

2007 Lexus RX 400H 

2WD 7TYXT03. 

3CC1 

AV SUV S2 35.7 135 35 95 

2007 Lexus RX 400H 

4WD 7TYXT03. 

3CC1 

AV SUV S2 34.3 126 34.3 91 

2007 Mercury 

Mariner 

Hybrid 7FMXT02. 

32ZE 

AV SUV S2 35.8 55 36.5 39 

35
 
MY Mfr Vehicle 

Model 

Engine 

Family 

Tran 

Fuel 

Economy 

Guide Class 

LEV- II 

Std 

Unadj 

City FE 

(mpg) 

City FE 

Inc Over 

Baseline 

(%) 

Unadj 

Cmb FE 

(mpg) 

Cmb FE 

Inc Over 

Baseline (%) 

2007 Toyota Highlander 

Hybrid 2WD 7TYXT03. 

3CC1 

AV SUV S2 35.7 103 35 69 

2007 Toyota Highlander 

Hybrid 4WD 7TYXT03. 

3CC1 

AV SUV S2 34.3 52 34.3 32 

DEDICATED ALTERNATIVE FUEL (CNG) VEHICLES 

2004 Honda Civic – CNG 4HNXV01 

.74W2 N/A S2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2005 Honda Civic - CNG 5HNXV01 

.7BF4 N/A S2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

Unless noted as a dedicated alternative fuel vehicle, all of the listed vehicles operate on gasoline, and some may also be flexible-fuel 

vehicles. 

MY = Model Year 

Mfr = Manufacturer 

Tran = Transmission 

Std = Standard 

Unadj = Unadjusted 

FE = Fuel Economy 

Inc = Increase 

Cmb = Combined city-highway 

S2 = SULEVII 

U2 = ULEVII 

2.4 Final Recommendation 

Based on the above discussion, EPA is proposing the Hybrid-to-gasoline vehicle 

comparison methodology. 

Chapter 3: List of Eligible Vehicles Based on the Hybrid-toGasoline Comparison Methodology 

As described in previous chapters, the hybrid-to-gasoline comparison vehicle 

comparison method is being proposed as the methodology for designating a 

comparable gasoline vehicle for purposes of this proposal. 

 Using the hybrid-to-gasoline vehicle comparison method as the comparison 

strategy, we would annually generate a list of eligible vehicles based on the Federal 

36
 
criteria and make it available to the Department of Transportation (DOT), who is 

primarily responsible for implementing HOV facilities and these associated exemptions. 

The federal list of eligible vehicles is based on the statutory criteria for fuel economy 

percent increases, but 23 U.S.C. 166 also provides an allowance to individual States 

that may implement this exemption to increase the stringency of the designated fuel 

economy increase percentages, using the described methodology and resulting 

baselines as the basis for comparisons. As a result, the vehicles that the EPA lists as 

eligible may not be eligible in all states. 

The potential federal list of vehicles eligible for an HOV occupancy exemption 

based on the emissions and fuel economy criteria is shown below in Table 3-1 and the 

potential list of vehicles based on California emission certification for the low emission 

criteria is shown below in Table 3-2. This list is only a proposed list and may change 

when the final rule is issued. Vehicles for model years 2008-2009 will be added to the 

list once they are available for use. Moreover, since states have the option to increase 

the stringency of the designated fuel economy percent increase values, an individual 

state’s list may differ from these lists. 

Table 3-1. Proposed List of Eligible Federally Certified Low Emission and EnergyEfficient Vehicles 

MY Mfr Vehicle 

Model 

Engine 

Family 

Tran 

Fuel 

Economy 

Guide 

Class 

Tier 2 

Std 

Unadj 

City FE 

(mpg) 

City FE 

Inc Over 

Baseline (%) 

Unadj 

Cmb FE 

(mpg) 

Cmb FE 

Inc Over 

Base-line 

(%) 

CARS 

2003 Honda Civic Hybrid 3HNXV0 

1.36CV AV Compact B5 52.6 52 56.0 75 

2003 Honda Civic Hybrid 3HNXV0 

1.36CV M5 Compact B5 50.0 59 55.7 74 

37
 
2003 Honda Insight 3HNXV0 

1.0PCE AV Two-seater B5 62.8 249 66.4 66 

2004 Honda Civic Hybrid 4HNXV0 

1.37CP AV Compact B5 52.6 50 56.0 75 

2004 Honda Civic Hybrid 4HNXV0 

1.37CP M5 Compact B5 50.0 42 55.7 74 

2004 Honda Insight 4HNXV0 

1.0NCE AV Two-seater B5 62.8 214 66.4 66 

2004 Toyota Prius 4TYXV0 

1.5MC1 AV Midsize B3 66.6 200 65.8 106 

2005 Honda Civic Hybrid 5HNXV0 

1.3YCV AV Compact B2 52.6 50 56.0 41 

2005 Honda Civic Hybrid 5HNXV0 

1.3YCV M5 Compact B2 50.0 42 55.7 40 

2005 Honda Insight 5HNXV0 

1.0XCE AV Two-seater B5 62.8 224 66.4 185 

2005 Honda Accord Hybrid 5HNXV0 

3.01B4 L5 Midsize B5 32.2 37 37.48 32 

2005 Toyota Prius 5TYXV0 

1.5MC1 AV Midsize B3 66.6 201 65.8 140 

2006 Honda Civic Hybrid 6HNXV0 

1.3XCP AV Compact B2 54.6 62 58.8 51 

2006 Honda Insight 6HNXV0 

1.0VK5 AV Two-seater B5 62.8 211 66.4 173 

2006 Toyota Prius 6TYXV0 

1.5MC1 AV Midsize B3 66.6 200 65.8 144 

2007 Honda Accord 

Hybrid 

7HNXV0 

3.0ZMC L5 Midsize B2 31.3 37 36.3 31 

2007 Honda Civic 

Hybrid 

7HNXV0 

1.3JCP AV Compact B2 54.6 67 58.8 51 

2007 Toyota Camry 

Hybrid 

7TYXV0 

2.4HC1 AV Midsize B3 44.2 66 45.9 44 

2007 Toyota Prius 7TYXV0 

1.5HC1 AV Midsize B3 66.6 210 65.8 154 

TRUCKS 

2005 Ford Escape Hybrid 

2WD 

5FMXT0 

2.31EE AV SUV B4 39.6 65 39.5 46 

2005 Ford Escape Hybrid 

4WD 

5FMXT0 

2.31EE AV SUV B4 36.6 78 36.7 57 

2006 Ford Escape Hybrid 

4WD 

6FMXT0 

2.32EE AV SUV B4 36.6 59 36.7 41 

38
 
2006 Ford Escape Hybrid 

FWD 

6FMXT0 

2.32EE AV SUV B4 39.6 59 39.5 42 

2006 Lexus RX 400H 

2WD 

6TYXT0 

3.3CC1 AV SUV B3 36.8 141 36.2 96 

2006 Lexus RX 400H 

4WD 

6TYXT0 

3.3CC1 AV SUV B3 34.3 124 34.3 86 

2006 Lexus Tribute Hybrid 

4WD 

6FMXT0 

2.32EE AV SUV B4 36.6 59 36.7 41 

2006 Mercury 

Mariner 

Hybrid 4WD 

6FMXT0 

2.32EE AV SUV B4 36.6 75 36.7 53 

2006 Toyota Highlander 

Hybrid 2WD 

6TYXT0 

3.3CC1 AV SUV B3 36.8 72 36.2 45 

2006 Toyota Highlander 

Hybrid 4WD 

6TYXT0 

3.3CC1 AV SUV B3 34.3 67 34.3 42 

2007 Ford Escape 

Hybrid 2WD 

7FMXT0 

2.32ZE AV SUV B3 35.8 55 36.5 39 

2007 Ford Escape 

Hybrid FWD 

7FMXT0 

2.32ZE AV SUV B3 41.1 64 40.6 45 

2007 Lexus RX 400H 

2WD 

7TYXT0 

3.3CC1 

AV SUV B3 35.7 135 35.0 95 

2007 Lexus RX 400H 

4WD 

7TYXT0 

3.3CC1 

AV SUV B3 34.3 126 34.3 91 

2007 Mercury Mariner 

Hybrid 4WD 

7FMXT0 

2.32ZE 

AV SUV B3 35.8 55 36.5 39 

2007 Toyota Highlander 

Hybrid 2WD 

7TYXT0 

3.3CC1 

AV SUV B3 35.7 67 35.0 40 

2007 Toyota Highlander 

Hybrid 4WD 

7TYXT0 

3.3CC1 

AV SUV B3 34.3 52 34.3 32 

DEDICATED ALTERNATIVE FUEL (CNG) VEHICLES 

2003 Honda Civic - CNG 3HNXV0 

1.73W3 N/A B2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2004 Honda Civic – CNG 4HNXV0 

1.74W0 N/A B2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2005 Honda Civic - CNG 5HNXV0 

1.7BF3 N/A B2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2003 Ford Crown Victoria 

- CNG 

3FMXV0 

4.6VP5 N/A B3 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2004 Ford Crown Victoria 

- CNG 

4FMXV0 

4.6VP5 N/A B3 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

39
 
Unless noted as a dedicated alternative fuel vehicle, all of the listed vehicles operate on gasoline, and some may also be flexible-fuel vehicles. 

MY = Model Year 

Mfr = Manufacturer 

Tran = Transmission type 

Int Wgt = Inertia Weight Class 

Std = Standard 

Unadj = Unadjusted 

FE = Fuel Economy 

Inc = Increase 

Cmb = Combined city-highway 

B = Bin 

40
 
Table 3-2. Proposed List of Eligible California-Certified Low Emission and EnergyEfficient Vehicles 

MY Mfr Vehicle 

Model 

Engine 

Family 

Tran 

Fuel 

Economy 

Guide Class 

LEV- II 

Std 

Unadj 

City FE 

(mpg) 

City FE 

Inc Over 

Baseline 

(%) 

Unadj 

Cmb FE 

(mpg) 

Cmb FE 

Inc Over 

Baseline (%) 

CARS 

2003 Honda Civic Hybrid 3HNXV01 

.36CV AV Compact S2 52.6 52 56.0 45 

2003 Honda Civic Hybrid 3HNXV01 

.36CV M5 Compact S2 50.0 59 55.7 46 

2003 Honda Insight 3HNXV01 

.0PCE AV Two-seater S2 62.8 249 66.4 201 

2004 Honda Civic Hybrid 4HNXV01 

.37CP AV Compact S2 52.6 50 56.0 41 

2004 Honda Civic Hybrid 4HNXV01 

.37CP M5 Compact S2 50.0 42 55.7 40 

2004 Honda Insight 4HNXV01 

.0NCE AV Two-seater S2 62.8 214 66.4 177 

2004 Toyota Prius 4TYXV01. 

5MC1 AV Midsize S2 66.6 200 65.8 139 

2005 Honda Civic Hybrid 5HNXV01 

.3YCV AV Midsize S2 52.6 50 56.0 41 

2005 Honda Civic Hybrid 5HNXV01 

.3YCV M5 Compact S2 50.0 42 55.7 40 

2005 Honda Insight 5HNXV01 

.0XCE AV Compact S2 62.8 224 66.4 185 

2005 Honda Accord 

Hybrid 

5HNXV03 

.01B4 L5 Midsize S2 32.2 37 37.48 32 

2005 Toyota Prius 5TYXV01. 

5MC1 AV Two-seater S2 66.6 201 65.8 140 

2006 Honda Civic Hybrid 6HNXV01 

.3XCP AV Midsize S2 54.6 62 58.8 51 

2006 Honda Insight 6HNXV01 

.0VK5 AV Compact S2 62.8 211 66.4 173 

2006 Toyota Prius 6TYXV01. 

5MC1 AV Two-seater S2 66.6 200 65.8 144 

2007 Honda Accord 

Hybrid 

7HNXV03 

.0ZMC L5 Midsize S2 31.3 37 36.3 31 

2007 Honda Civic Hybrid 7HNXV01 

.3JCP AV Midsize S2 54.6 67 58.8 51 

2007 Toyota Camry Hybrid 7TYXV02. 

4HC1 AV Midsize S2 44.2 66 45.9 44 

2007 Toyota Prius 7TYXV01. 

5HC1 AV Midsize S2 66.6 210 65.8 154 

41
 
MY Mfr Vehicle 

Model 

Engine 

Family 

Tran 

Fuel 

Economy 

Guide Class 

LEV- II 

Std 

Unadj 

City FE 

(mpg) 

City FE 

Inc Over 

Baseline 

(%) 

Unadj 

Cmb FE 

(mpg) 

Cmb FE 

Inc Over 

Baseline (%) 

TRUCKS 

2005 Ford Escape 

Hybrid 2WD 

5FMXT02. 

31EE AV SUV S2 39.6 65 39.5 46 

2005 Ford Escape 

Hybrid 4WD 

5FMXT02. 

31EE AV SUV S2 36.6 78 36.7 57 

2006 Ford Escape 

Hybrid 4WD 

6FMXT02. 

32EE AV SUV S2 36.6 59 36.7 41 

2006 Ford Escape 

Hybrid FWD 

6FMXT02. 

32EE AV SUV S2 39.6 59 39.5 42 

2006 Lexus RX 400H 

2WD 

6TYXT03. 

3CC1 AV SUV S2 36.8 141 36.2 96 

2006 Lexus RX 400H 

4WD 

6TYXT03. 

3CC1 AV SUV S2 34.3 124 34.3 86 

2006 Mazda Tribute 

Hybrid 4WD 

6FMXT02. 

32EE AV SUV S2 36.6 59 36.7 41 

2006 Mercury 

Mariner 

Hybrid 4WD 

6FMXT02. 

32EE AV SUV S2 36.6 75 36.7 53 

2006 Toyota Highlander 

Hybrid 2WD 

6TYXT03. 

3CC1 AV SUV S2 36.8 72 36.2 45 

2006 Toyota Highlander 

Hybrid 4WD 

6TYXT03. 

3CC1 AV SUV S2 34.3 67 34.3 42 

2007 Ford Escape 

Hybrid 4WD 7FMXT02. 

32ZE 

AV SUV S2 35.8 55 36.5 39 

2007 Ford Escape 

Hybrid FWD 7FMXT02. 

32ZE 

AV SUV S2 41.1 64 40.6 45 

2007 Lexus RX 400H 

2WD 7TYXT03. 

3CC1 

AV SUV S2 35.7 135 35 95 

2007 Lexus RX 400H 

4WD 7TYXT03. 

3CC1 

AV SUV S2 34.3 126 34.3 91 

2007 Mercury 

Mariner 

Hybrid 

7FMXT02. 

32ZE AV SUV S2 35.8 55 36.5 39 

42
 
MY Mfr Vehicle 

Model 

Engine 

Family 

Tran 

Fuel 

Economy 

Guide Class 

LEV- II 

Std 

Unadj 

City FE 

(mpg) 

City FE 

Inc Over 

Baseline 

(%) 

Unadj 

Cmb FE 

(mpg) 

Cmb FE 

Inc Over 

Baseline (%) 

2007 Toyota Highlander 

Hybrid 2WD 7TYXT03. 

3CC1 

AV SUV S2 35.7 103 35 69 

2007 Toyota Highlander 

Hybrid 4WD 7TYXT03. 

3CC1 

AV SUV S2 34.3 52 34.3 32 

DEDICATED ALTERNATIVE FUEL (CNG) VEHICLES 

2004 Honda Civic – CNG 4HNXV01 

.74W2 N/A S2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

2005 Honda Civic - CNG 5HNXV01 

.7BF4 N/A S2 DEDICATED ALTERNATIVE FUEL (CNG) VEHICLE 

Unless noted as a dedicated alternative fuel vehicle, all of the listed vehicles operate on gasoline, and some may also be flexible-fuel 

vehicles. 

MY = Model Year 

Mfr = Manufacturer 

Tran = Transmission 

Int Wgt = Inertia Weight Class 

Std = Standard 

Unadj = Unadjusted 

FE = Fuel Economy 

Inc = Increase 

Cmb = Combined city-highway 

S2 = SULEVII 

U2 = ULEVII 

43
 
References 

Energy Policy Act of 2005. Public Law 109-58, August 8, 2005. 

Hellman, Karl, and Robert Heavenrich. “Light-Duty Automotive Technology and Fuel 

Economy Trends: 1975 Through 2004” (FE Trends). EPA420-R-04-001, 2004. 

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

Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users 

(SAFETEA-LU). Public Law 109-59, Section 1121 HOV Facilities. August 10, 

2005. 

U.S. Department of Transportation (DOT), Federal Highway Administration (FHWA). 

“Safe Accountable Flexible Efficient Transportation Equity Act: A Legacy for 

Users.” http://www.fhwa.dot.gov/safetealu/ 

U.S. DOT, National Highway Traffic and Safety Administration (NHTSA). “Vehicles and 

Equipment.” 

http://www.nhtsa.dot.gov/portal/site/nhtsa/menuitem.d0b5a45b55bfbe582f57529c 

dba046a0/ 

U.S. Environmental Protection Agency (EPA), Office of Transportation and Air Quality 

(OTAQ). “Basic Information.” 

http://www.epa.gov/fueleconomy/basicinformation.htm 

U.S. EPA, OTAQ. “Certification and Fuel Economy Information System (CFEIS).” 

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

U.S. EPA, OTAQ. “Green Vehicle Guide.” www.epa.gov/greenvehicles 

U.S. EPA, OTAQ. “Notice of Proposed Rulemaking: Revisions to Improve Calculation of 

Fuel Economy Estimates.” 71 FR 5426, February 9, 2006. 

http://www.epa.gov/fueleconomy/regulations.htm#estimates 

U.S. EPA, OTAQ. “Regulations and Standards.” 

http://www.epa.gov/fueleconomy/regulations.htm#cafe 

44