P.1 

OAR Box 1830 

Prepped by Ollie Stewart 

Document Number: 

197) IV-C-164 

Docket Number: 

A-87-11 

Printed 11/13/2008 7:21:02 AM Sheet 197 of 232 
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i ^ 

(A) UNITED STATES ENVIRONMENTAL PROTECTION AGENCY I \l~ ^ " • *° 1 

ANN ARBOR. MICHIGAN 48105 

APR 2 7 1989 

OFFICE OF 

AIR AND RADIATION 

mm 

MAY 31989 

EPA AIR DOCKET 

Clarence M. Ditlow 

Center for Auto Safety 

2001 S Street, NW 

Suite 410 

Washington, DC 20009 

Dear Mr. Ditlow: 

In response to your letter of March 14, 1989, enclosed is 

an excerpt from a December 22, 1988 EPA memorandum entitled 

"Onboard and Evaporative Control System Cost Estimates for the 

Supplemental Notice of Proposed Rulemaking." In this, excerpt 

you will find EPA's most recent analysis of the fuel economy 

impacts of onboard refueling control. Although a number of 

updated values and several new assumptions have gone into*, th-^s 

analysis, it is never-the-less a continuation ^of^ tiie 

methodology used in the fuel economy impact analysis .presented 

in the July, 1987 Response to Public Comments document which is 

also enclosed. Pages 2-113 to 2-143 of that document should Be 

referred to as well when trying to more fully understand EPA's 

methodology in calculating the fuel economy impact of onboard. 

As is explained in the enclosed excerpt, the fuel savings 

occur as a result of the capture and subsequent utilization of 

fuel vapors in the engine that absent controls were merely 

released to the atmosphere. The fuel vapor controlled is 

credited on an equal energy basis as liquid gasoline under the 

assumption that the engine can utilize the vapor with the same 

efficiency as the fuel from the vehicle's fuel distribution 

system. 

In addition to this fuel economy benefit, however, is a 

fuel economy detriment associated the added weight of the 

vehicle for the vapor control hardware. Here, however, is the 

major difference between the 1987 analysis and the current 

analysis. Under the assumption that onboard refueling control 

is incremental to volatility control and improved evaporative 

control, the majority of the vehicle changes required for 

onboard would have already been required to control excess 

evaporative and running loss emissions. As a result, there is 
P.3 

no weight penalty associated with onboard refueling control (it 

/is applied to improved evaporative control). Thus, instead of 

only a marginal fuel economy benefit for onboard if it is not 

assumed incremental to improved evaporative control (as in the 

1987 analysis), it becomes comparatively significant. In 

addition, it is worth noting that the fuel economy benefits of 

onboard controls may be even greater. Recent fuel economy 

trend analyses and projections suggest that future vehicle fuel 

economies may not be as large as had been predicted. Thus, 

onboard fuel . consumption benefits could increase by 

approximately 25 percent over the values in Table 14 of the 

enclosed excerpt. 

The fuel economy impact is significant to the cost 

effectiveness of onboard refueling controls, but is 

never-the-less small relative to overall fuel economy. Since 

refueling emissions are on the order of 5.4 g/gal (assuming 

summer volatility control to 9 psi) representing less than 0.2 

percent of a gallon of gasoline (adjusted for vapor energy 

content and density compared to that of liquid gasoline), the 

maximum fuel economy increase is limited to this level. While 

there should be a small increase in on-road fuel economy 

associated with onboard control, there should be no impact on 

CAFE fuel economy, since CAFE fuel economy is not measured as 

miles driven per gallon of fuel from the tank, but is rather 

calculated using a mass balance of the exhaust emissions 

independent of where the fuel comes from. 

Please contact Paul Machiele of my staff at (313) 668-4264 

if you have any questions regarding the enclosed analyses. 

CHARLES L. GRAY, JR. 

Charles L. Gray, Jr. 

Director 

Emission Control Technology Division 

Enclosures 

6973W 
P.4 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

ANN ARBOR. MICHIGAN 48105 

DEC 2 2 I988 

OFFICE OF 

AIR AND RADIATION 

MEMORANDUM 

SUBJECT: Onboard and 

Estimates for 

Rulemaking 

Evaporative Control System ' Cost 

the Supplemental Notice of Proposed 

FROM: 

TO: 

THRU: 

Jean Schwendeman, Mechanical Engineer 

Standards Development and Support Branc 

The Record 

Glenn W. Passavant, Senior Project Manage 

Standards Development and Support Branch 

•X' < •'. t '-it.' 

r yJLrtti&M***^ 

Richard A. Rykowski, Senior Project Manage 

Standards Development and Support Branch * # S 

Introduction 

This memorandum describes in detail the new cost estimates 

for the improved evaporative system and the onboard refueling 

vapor, recovery system, as discussed in the Supplemental Notice 

of Proposed Rulemaking. The analysis for the improved 

evaporative system was performed for both 9.0 and 11.5 psi RVP 

certification fuel. As is discussed further below, the onboard 

analysis assumes a 9.0 psi RVP certification fuel. 

The estimates will be shown as incremental costs for each 

additional level of control. The costs for "improved" 

evaporative systems are incremental to those for "excess" 

evaporative systems and the revised costs for onboard systems 

are incremental to both of these. For this memorandum, each of 

the different control levels are defined as follows: 
P.5 

-5-

Table lA 

Excess Evaporative System Costs 

(Incremental to Current Evap')* 

9.0 psi RVP Certification Fuel 

Vehicle 

LDV 

LDT 

HDGV 

Vehicle 

Cost Increase 

1.45 

1.85 

3.35 

weight 

Penalty 

o.oo 

0.00 

0.00 

Fuel Net Cost 

Recovery Credit** to Owner 

N.A. 

N.A. 

N.A. 

Sales Weighted Net Cost 

1.45 

1.85 

3.35 

1.60 

Table IB 

Improved Evaporative System Costs 

(Incremental to Excess Evap)* 

9.0 psi RVP Certification Fuel 

Vehicle 

LDV 

LDT 

HDGV 

Vehicle . 

Cost Increase 

9.65 

13.40 

11.25 

Weight 

Penalty 

0.50 

1.15 

0.60 

Fuel Net Cost. 

Recovery Credit to Owner 

12.30 

20.6 5 

38.7 5 

-2.15 

-6.10 

-26.90 

Sales Weighted Net Cost -3.70 

* * 

Costs are in RPE for 1988 dollars rounded to the nearest nickel. 

Sales Weights: LDV1 73.2%; LDT 24.3%; HDGV 2.5%. 

The total fuel recovery credit of excess evaporative systems would 

be the result of any vehicle changes and also of matching 

certification and in-use fuel RVPs. It is difficult to determine 

the portion of the credit due solely to vehicle changes, so none are 

used here. 
-6-

P.6 

Table 1C 

Revised Onboard Control System Costs 

(Incremental to Improved Evap)* 

9.0 psi RVP Certification Fuel 

Vehicle 

LDV 

LDT 

HDGV 

Vehicle 

Cost Increase 

0.90 

1.50 

5.20 

Weight 

Penalty 

0.00 

0.00 

0.00 

Fuel 

Recovery Credit 

4.20 

6.65 

12.60 

Sales Weighted Net Cost 

Net Cost 

to Owner 

-3.30 

-5.15 

-7.40 

-3.90 

Vehicle 

LDV 

LDT 

HDGV 

Table ID 

Total Costs for Onboard and 

Evaporative System Changes* 

9.0 psi RVP Certification Fuel 

Vehicle 

Cost Increase 

12.00 

16.75 

19.80 

Weight 

Penalty 

0.50 

1.15 

0.60 

Fuel Net Cost 

Recovery Credit to Owner 

16.50 

27.3 0 

51.3 5 

Sales Weighted Net Cost 

-4.00 

-9.40 

-30.95 

-6.00 

Costs are in RPE for 1988 dollars rounded to the nearest nickel 

Sales Weights: LDV 73.2%; LDT 24.3%; HDGV 2.5%. 
P.7 

-34 - 1 

C. Recovery Credits ] 

1 

) 

(i) Weight Penalty 

The weight penalty for the improved evaporative system was 

calculated using the same method as was used in the original 

onboard proposal. The components which were included in the 

weight calculation are the canister, vapor lines, and the vapor 

vent/rollover valve. A carbon density of 0.66 lb./L. and a 

body weight of 0.445 pounds for a 1.5 liter canister are the 

same values used in the original onboard proposal. The body 

weight of other cylindrical canister sizes is assumed to be 

proportional to the ratio of the squares of the canister 

t 

The following discussion on recovery credits (weight 

penalty and fuel recovery) is specific for each system. A net 

recovery,credit has two components: a fuel recovery credit and 

a weight penalty. The fuel recovery credit accounts for the 

fuel that is saved when fuel vapors are captured by a vapor 

recovery system and utilized. The weight penalty accounts for 

a loss in fuel economy due to the slight increase in vehicle 

weight added by the vapor recovery system. The net recovery 

credit is the difference between the money saved from fuel 

recovery and the increased fuel consumption cost to move a 

slightly heavier vehicle. The recovery credits for excess 

evaporative systems will be discussed first. Recovery credits 

for improved evaporative systems and onboard systems will 

follow. j 

1. Excess Evaporative System 

There was no weight penalty associated with the excess 

evaporative system of the original volatility proposal since 

there were no changes necessary in vehicle hardware at 9.0 RVP 

fuel which would result in a weight penalty. The fuel recovery 

credit for these systems is a function of not only changes to 

the vehicle control system but also of change in commercial 

fuel volatility (both the matching of in-use and certification, 

fuel RVP and the RVP level at which this is done). The portion 

of the excess evaporative fuel recovery credit due solely to 

vehicle controls is difficult to determine. Also, if the 

excess evaporative fuel recovery credit is included, then the 

increase in lifetime fuel cost to the vehicle owner due to 

commercial fuel volatility control must also be included. 

Since the purpose of this analysis is only to determine vehicle 

control system costs and not volatility control costs, the 

excess evaporative fuel recovery credit was not included here. 

2. Improved Evaporative Systems 

The net recovery credits for the improved evaporative system 

were calculated for 9.0 psi RVP fuel. The weight penalty will 

be discussed first. 

* ^ 
P.8 

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radii. (The square of the radius for a 1.5 L canister, 

assuming the height to be equal to the diameter, is 38.5 

cm2). Tables 11A and 11B show the calculations for the 

change in canister weights between the improved and excess j 

evaporative systems. The calculations showing the change in ' 

weight due to the increased diameter of the vapor lines are j 

shown in Tables 12A and 12B. There is no difference in weight' ] 

between the improved evaporative vapor vent/rollover system ! 

valve and the revised onboard system valve. Also, EPA did not J 

subtract the weight of any possible current system vent valve i 

from that of the improved evaporative valve so that the full ' 

valve weight was allocated to the improved evaporative system. 

The same weight was used as that which was measured for the 

valve on the original onboard proposal system. This is a 

conservative estimate since the original onboard valve was a 

heavier fillneck mounted valve made of steel while the improved 

evaporative valve is plastic and mounted on the tank. The 

values below have been weighted by sales for single and dual 

fuel tanks. 

t 
Table H A 

Evaporative System Canister Weights, LDVs and LDTs; 

9.0 psi RVP fuel. 

Canister Carbon + Canister Body 

Size Weight Material Weight 

Total Canister 

Weight 

LDVs 

Excess Evaporative System 1.3 L 

Improved Evaporative System 2.7 L 

0.9 lbs. 0.4 lbs. 1.3 lbs. 

1.8 lbs. 0.7 lbs. 2.5 lbs. 

Incremental Canister Weight 

for Improved Evaporative System 1.2 lbs. 

LDTs 

Single Tank 

Excess Evaporative System 1.7 L 

Improved Evaporative System 3.9 L 

1.1 lbs. 0.5 lbs. 1.6 lbs. 

2.6 lbs. 0.8 lbs. 3.4 lbs. 

Incremental Canister Weight 

for Improved Evaporative System 1.8 lbs. 

Dual Tank 

Excess Evaporative System 2 § 1.7 L 

Improved Evaporative System 2 @ 3.9 L 

2.2 lbs. 1.0 lbs. 3.2 lbs. 

5.2 lbs. 1.6 lbs. 6.8 lbs. 

Incremental Canister Weight 

for Improved Evaporative System 3.6 lbs. 

i 

Ul 

I 

LDT Weighted (single and dual) = (80%)(1.8 lbs.) +(20%)(3.6 lbs) = 2.2 lbs. 
Table 11B 

Evaporative System Canister Weights, HDGVs; 

9.0 psi RVP fuel. 

Canister Carbon -l- Canister Body = Total Canister 

Size Weight Material Weight Weight 

Excess Evaporative System 4.0 L 2.6 lbs. 0.9 lbs. 3.5 lbs. 

(From Original Volatility 

Proposal. Average of all 

HDGV classes, and both 

single and dual tanks) 

Improved Evaporative System 

Class lib 

Single Tank 4.3 L 2.8 lbs. 0.9 lbs. 3.7 lbs. 

Dual Tank 2 @ 4.3 L 5.6 lbs. 1.8 lbs. 7.4 lbs. 

Weighted (Single and Dual) = (80%)(3.7 lbs) + (20%)(7.4 lbs) = 4.4 lbs. 

Class lib Incremental Canister Weight 

for Improved Evaporative System =4.4-3. 5 =0.9 lbs. 

Class VI 

Single Tank 7.0 L 4.6 lbs. 1.2 lbs. 5.8 lbs. 

Dual Tank 2 @ 10.1 L 13.4 lbs. 3.2 lbs. 16.6 lbs. 

Weighted (Single and Dual) = (85%)(5.8 lbs.) + (15%)(16.6 lbs) = 7.4 lbs. 

Class VI Incremental Canister Weight 

for Improved Evaporative System =7.4-3. 5 =3.9 lbs. 

i 

I 
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Table 12A 

Improved Evaporative System Vapor Line Weights; LDVs and LDTs 

Net incremental weight of the improved evaporative system vapor 

lines is the difference in weight between the 3/8" I.D. fuel 

tank vapor vent line on the improved evaporative system and the 

1/4" I.D. purge line on the excess evaporative system. 

Excess Evaporative 

Purqe Line 

2 ft. of 1/4" I.D. Steel: 

1 ft. of 1/4" I.D. Rubber: 

2 ft. 

1 ft. 

X 0.06 lb/ft = 0.12 

X 0.08 lb/ft = 0.08 

0.20 

lb 

lb 

lb 

Improved Evaporative 

Fuel Tank Vent Line 

2 ft. of 3/8" I.D. Steel: 

1 ft. of 3/8" I.D. Rubber: 

2 ft. X 0.12 lb/ft 

1 ft. X 0.12 lb/ft 

0.24 lb 

0.12. lb 

0.36 lb 

Total Incremental Weight LDVs and LDT Single Tank 

0.36 lb - 0.20 lb = 0.2 lbs. 

Total Incremental Weight LDT Dual Tank 

(80%)(0.20 lb) + (20%)(0.40 lb) - 0.2 lbs. 
P.12 

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Table 12B 

Improved Evaporative System Vapor Line Weights; HDGVs 

Net incremental weight of the improved evaporative system vapor 

lines is the difference in weight between the 1/2" I.D. rubber 

fuel tank vapor vent line on the improved evaporative system 

and the 3/8" I.D. rubber fuel tank vapor vent line on the 

excess evaporative system. 

Excess Evaporative System 

Fuel Tank Vapor Vent Line 

Class lib: 

Class VI: 

Single Tank 3/8": 

Dual Tanks : 

Single Tank 3/8": 

Dual Tanks : 

Improved Evaporative System 

Fuel Tank Vapor Vent Line 

Class lib: Single Tank 1/2" 

Dual Tanks 

Class VI: 

8 ft. X 0.12 lb/ft, 

2 X single 

15 ft. X 0.16 lb/ft 

2 X single 

0.96 lbs, 

1.92 lbs. 

1.8 

3.6 

lbs 

lbs 

Single Tank 1/2": 

Dual Tanks : 

8 ft. X 0.16 lb/ft 

2 X single 

15 ft. X 0.16 lb/ft 

2 X single 

Total Incremental Weight of Vapor Lines 

Class lib: Single Tank: 1.28 lbs. - 0.96 lbs. 

Dual Tank : 2.56 lbs. - 1.92 lbs. 

Weighted: (80%)(0.32) + (20%)(0.64) 

Class VI: Single Tank: 2.4 lbs. - 1.8 lbs. 

Dual Tank 4.8 lbs. - 3.6 lbs. 

Weighted: (85%)(0.6) + (15%)(1.2) 

1.28 lbs . 

2.5 6 lbs . 

2.4 0 lbs . 

4.8 0 lbs . 

0.32 lbs. 

0.64 lbs. 

0.40 lbs. 

0.6 lbs . 

1.2 lbs . 

0 .7 lbs . 

i 

j 

i 
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Vapor Vent/Rollover Valve Weight 

LDV 

LDT: 

HDGV lib: 

HDGV VI: 

(80%)(0.4) +(20%)(0.8) 

(80%)(0.4) + (20%)(0.8) 

(85%)(0.4) + (15%)(0.8) 

0.4 lbs 

0.5 lbs 

0.5 lbs 

0.5 lbs 

The total change in vehicle weight and the corresponding 

effect on fuel economy can now be calculated. The same format 

as that used in the original onboard proposal was used. 

Component LDV 

Canister (Carbon, Body) 

Vapor Lines 

Valve 

Total Weight (lbs) 

Weight Multiplication 

Factor (1.1) 

Ave. Vehicle Weight (lbs) 

Percent Change in Weight 

Sensitivity Factor 

(dimensionless) 

Percent Change in Fuel 

Economy (mpg) 

Projected Fuel 

Economy (mpg) 

Projected Avg. Life (miles) 

LDT lib VI 

1.2 lbs 2.2 lbs 0.9 lbs 3.9 lbs 

0.2 

0.4 

1.8 

2.0 

3,082 

0.064% 

-0.329 

0.2 

0.5 

2.9 

3.2 

3,832 

0.083% 

-0.402 

0.4 

0.5 

1.8 

2.0 

9,250 

0.021% 

-0.402 

0.7 

0.5 

5.1 

5.6 

22,500 

0.025% 

-0.402 

-0.021% -0.033% -0.009% -0.010% 

24.61 18.43 11.16 

100,000 120,000 110,000 

Lifetime Fuel Consumption 

(gal) 4,063 

Lifetime Weight Penalty 

(gal) 0.9 

6,511 

2.2 

9,857 

0.8 

6.07 

110,000 

18,122 

1.8 

HDGVs (weighted) = 1.1 gal 

The total weight penalty cost over the lifetime of the 

vehicle can now be calculated using the same discount factors 

and yearly fuel recovery fractions as used in the original 

onboard proposal. A fuel price of $0.82 per gallon is used, 

which is the same as was used in the original volatility 

proposal. This price does not include taxes and is based upon 

a crude oil price of $20 per barrel. The resulting weight 

penalty is: $0.48 for LDVs, $1.16 for LDTs, and $0.60 for 

HDGVs. 

* H» 
-41-

(ii) Fuel Recovery Credit 

The fuel recovery credits ($ per vehicle lifetime) are j 

based on the emission factor reductions (grams HC per mile) j 

resulting from improved evaporative control systems. These * 

emission factor reductions, shown in Table 13, were taken from ] 

a recent EPA analysis. [5] It was assumed that 80 percent of j 

current running loss emissions would be controlled by the 

implementation of improved evaporative controls. The total \ 

emission factor reductions for each vehicle type were then | 

multiplied by their expected lifetime mileages discounted at a : 

rate of 10 percent (65420 for LDVs, 80932 for LDTs and 71715 j 

for HDVs) to yield total discounted lifetime emission • 

reductions. These emission reductions (assumed to be all [ 

butane) were then valued at $290.32 per ton based on work j 

performed in the original volatility control proposal. (This j 

assumes a cost per gallon of gasoline of $0.82 and a combustion \ 

efficiency of the hydrocarbon vapor equivalent to that of 

liquid fuel; i.e., an evaporative recovery factor of 1.0.) The 

fuel recovery credits on a vehicle lifetime basis are then: 

Vehicle Type 9 RVP Fuel 11.5 RVP Fuel 

LDV $12.31 $42.83 

LDT $20.67 $63.35 

HDV $38.74 $96.07 

The decrease in the credit with 9 RVP fuel results from the 

fact that a great deal of evaporative emission reductions occur 

as a result of volatility control. These volatility-related 

emission reductions are not reflected in the calculations above. 

The net recovery credit for the improved evaporative 

system of each vehicle type is the difference between the fuel 

recovery credit and the weight penalty for that system. These 

values are shown in Table IB. 

3. Onboard System 

The net recovery credits used in the original onboard 

proposal were adjusted to account for the changes made in the 

supplemental proposal. Since the fuel tank sizes, and fuel 

economies did not change in the reproposal, the quantity of 

fuel recovered was not changed. However, the simplified system 

has fewer components than before and even results in the 

removal of the external vent line for LDVs, LDTs and Class lib 

HDGVs. The canister is only slightly larger than the canister 

proposed for the enhanced evaporative system. Therefore, EPA 

considers the weight penalty of onboard systems incremental to 

improved evaporative systems to be essentially zero. In fact, 

there could be a slight weight decrease. 
-42-

Table 13 

Emission Factor Reductions Resulting 

From Improved Evaporative Controls,5] 

9 RVP Fuel 

LDV LDT HDV 

High Temperature Diurnal 

Evaporative Emissions (g/mi) 0.34 0.55 1.44 

Running Losses (g/mi) 0.248 0.248 0.248 

Total Emission Factor (g/mi) 0.588 0.789 1.688 

Discounted Lifetime 

Emissions (kg) 38.5 64.6 121.0 

11.5 RVP Fuel 

Discounted Lifetime 

Emission (kg) 133.0 198.0 300.2 

LDV LDT HDV j 

High Temperature Diurnal . j 

Evaporative Emissions (g/mi) 0.67 1.07 2.81 j 

Running Losses (g/mi) 1.376 1.376 1.376 

Total Emission Factor (g/mi) 2.046 2.446 4.186 
P.16 

-43-

Since there is no weight penalty, the net recovery credit 

is based solely on the fuel recovery credit. The fuel cost was 

adjusted from $0.98/gal to $0.82/gal in order to be consistent 

with the value used in the original volatility proposal. The 

discount factors and yearly fuel recovery fractions used in the 

original proposal were also applied in this analysis. The fuel 

recovery credits for 9.0 psi RVP fuel are shown in Table 14, 

along with the quantity of fuel saved during the vehicle's 

life. These credits are also shown in Table 1C. 
P.17 

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Table 14 

Fuel Recovery Credits for Onboard Systems* 

9.0 psi RVP 

Fuel Savings 

Vehicle (gal/life) (1988$) 

LDV 7.8 $4.20 

LDT 12.6 6.65 

HDGV 23.6 12.60 

Values Tess than $10 were rounded off to the nearest 

nickel. Values greater than $10 were rounded off to the 

nearest dime. 
P.18 

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Summary . j 

The cost analysis for the supplemental proposal for . 

improved evaporative and onboard systems were changed only 

where necessary to reflect new requirements, changes in design 

concepts and improved modeling. Components and other cost 

areas not affected were only adjusted for inflation so that all 

values are in 1988 dollars. The resulting cost estimates 

represent "typical" vehicles. The actual cost for individual 

models will vary. A summary of the costs for excess 

evaporative, improved evaporative and revised onboard systems 

is presented in the following paragraphs. These system costs 

were shown in Tables 1A through ID. 

_ 

The estimated net costs for excess evaporative systems I 

incremental to current evaporative systems when 9.0 RVP fuel is ] 

used are $1.45, $1.85 and $3.35 for LDVs, LDTs and HDGVs j 

respectively. These costs are entirely due to vehicle cost j 

increases since there is no incremental weight penalty and the I 

fuel recovery credit can not be included in this analysis for. ] 

reasons already explained. However, this is conservative since 

some of the recovery credit is attributable to vehicle \ 

charges. The sales weighted net incremental cost for excess ' 

evaporative systems is $1.60 in RPE. 1 

The estimated cost for improved evaporative systems \ 

incremental to excess evaporative systems is $9.65, $13.40, and 

$11.25 for LDVs, LDTs, and HDGVs, respectively, for 9.0 psi RVP -j 

certification fuel. If the net recovery credits are included, i 

the improved evaporative systems should result in a net < 

incremental savings of $2.15, $6.10 and $26.90 for LDVs, LDTs ] 

and HDGVs respectively; The net savings weighted by vehicle • 

class is $3.70. 1 

The estimated cost for simplified onboard systems 

incremental to improved evaporative systems is $0.90, $1.50, 

and $5.20 for LDVs, LDTs, and HDGVs respectively (for 9.0 psi 

RVP certification fuel). If the net recovery credits are 

included, the onboard systems should result in a net savings 

for the vehicle owner. The estimated net incremental savings 

are $3.30, $5.15 and $7.40 for LDVs, LDTs, and HDGVs, 

respectively (9.0 psi RVP). The net incremental savings 

weighted by vehicle class sales is $3.90. 

The total vehicle costs for the onboard refueling and 

evaporative system changes (both excess and improved 

evaporative) are $12.00, $16.75 and $19.80 for LDVs, LDTs and 

HDGVs respectively incremental to current evaporative systems. 

If the net recovery credits are included a net savings is ! 

realized by the vehicle owner of $4.00, $9.40 and $30.95 in the 

three vehicle classes. The sales weighted net incremental 

savings is $6.00. 
-46-

References 

1. Draft Regulatory Impact Analysis, "Control of 

Gasoline Volatility and Evaporative Hydrocarbon Emissions from 

New Motor Vehicles," U.S. EPA, Office of Air and Radiation, 

Office of Mobile Sources, July 1987. Public Docket A-85-22, 

III-B-l. 

2. "Evaluation of Air Pollution Regulatory Strategies 

for Gasoline Marketing Industry - Response to Public Comments," 

U.S. EPA, Office of Air and Radiation, Office of Air Quality 

Planning and Standards, and Office of Mobile Sources, 

(EPA450/3-84-012c), July 1987. 

3. Draft Regulatory Impact Analysis, Proposed Refueling 

Emission Regulations for Gasoline - Fueled Vehicles — Volume 

II - Additional Analysis of Onboard Controls 

(EPA-450/3-87-001b), U.S. EPA, Office of Air and Radiation, 

Office of Air Quality Planning and Standards, and Office of 

Mobile Sources, July 1987. 

4. "PT Model Description and Users Guide," David B. 

Bartus, U.S. EPA, SDSB, August 10, 1988. 

5. "Effect of Running Losses and Excess Evaporative 

Emissions on Future VOC Emission Inventories," Memorandum from 

Richard Rykowski, EPA/OMS/ECTD/SDSB, to the Record, December 

22, 1988. 

-> 

-«<fl 

J