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U.S. Department of Energy,Vehicle Technologies Program, Advanced Vehicle Testing Activity (AVTA)
British Columbia PHEV Demonstration Workshop – AVTA’s PHEV Testing and Demonstration Activities
Jim FrancfortBC Hydro and Powertech LabsVancouver, British Columbia. October 2008
This presentation does not contain any proprietary or sensitive information
2
AVTA Background and Goals• The Advanced Vehicle Testing Activity (AVTA) is part of
DOE’s Vehicle Technologies Program. The AVTA mission is to support DOE’s strategic goal to reduce the nation’s dependence on foreign oil
• The Idaho National Laboratory (INL) and Electric Transportation Engineering Corporation (ETEC) conduct the AVTA. Argonne National Laboratory performs dynamometer testing
• INL is a 890 square mile eastern Idaho based DOE multi-program laboratory with 3,600 staff
• The AVTA goals: – Provide benchmark data to technology modelers,
research and development programs, vehicle manufacturers (via VSATT), and target and goal setters
– Assist fleet managers in making informed vehicle purchase, deployment and operating decisions
3
AVTA Testing History• Plug-in hybrid electric vehicles (PHEV)
– 9 models, ~75 vehicles• Hybrid electric vehicles (HEV)
– 14 models, 4 million test miles• Hydrogen ICE (internal combustion engine) vehicles
– 7 models, 400,000 test miles• Full-size electric vehicles
– 40 EV models, 5+ million test miles• Neighborhood electric vehicles
– 16 models, 200,000 test miles• Urban electric vehicles
– 3 models, 1 million test miles
4
PHEV Questions • Are PHEVs technically and economically feasible as a
transportation option?• What are the petroleum savings and electricity demands?• Will fleets and the public adapt to plugging in (charging)
PHEVs to maximize mpg?• Is a two-fuel scenario a difficult transition?• What are the charging infrastructure needs, including
110V versus 220V? Fast charging?• V2Grid – economic benefit or liability to the vehicle
operator?
• To answer these questions, the AVTA is testing and field demonstrating nine different PHEV models and charging infrastructure
5
9 PHEVs Models in Testing/Demonstrations • Hymotion Prius • Hymotion Escape• EnergyCS Prius• Electrovaya Escape• Hybrids Plus Escape• Hybrids Plus Prius• Manzanita Prius (lead acid)• Ford Escape• Renault Kangoo (NiCad)• (Vehicles equipped with
lithium traction batteries unless noted)
6
PHEV Testing Objectives• Perform independent testing of PHEVs, using:
– Baseline performance testing – closed test tracks and dynamometers
– Accelerated testing – dedicated drivers operating on defined onroad loops
– Fleet testing – everyday unstructured use, with onboard data loggers
• Document battery life, charging patterns and demand profiles
• Document vehicle operations, fuel use (both gasoline and electricity) and infrastructure requirements (110 versus 220, offpeak and V2Grid charging)
• Document driver influences on fuel use• Document PHEV life-cycle costs
7
PHEV Baseline Performance Testing• ETEC conducts initial track testing near Phoenix, AZ
– Includes coastdown (determination of dynamometer coefficients), acceleration, top speed, braking, charging, and durability testing
• Argonne 5-day dynamometer testing regime includes: – Charge depleting and sustaining test cycles, as well
as hot and cold starts– At least 26 UDDS (Urban Dynamometer Driving
Schedule) and HWFEDS (Highway Fuel Economy Driving Schedule) dynamometer test cycles
8
• 5 kWh A123Systems (Li) V1 and Prius packs (AC kWh)Hymotion Prius – UDDS Fuel Use
Hymotion PHEV Prius MPG & kWh - UDDS Testing
01020
30405060
708090
100110
120130140150
160170180
7 15 22 30 37 45 52 60 67 75 82 90 97 105 112 119 127 134 142
MPG
0.00.51.0
1.52.02.53.0
3.54.04.55.05.5
6.06.57.07.5
8.08.59.0
Each Bar - 1 UDDS Test Cycle, Labeled by Cumulative Miles
kWh
MPG per UDDS Test Cumulative AC kWh Cumulative MPG
9
Hymotion Prius – HWFETS Fuel Use• 5 kWh A123Systems (Li) V1 and Prius packs (AC kWh)
Hymotion PHEV Prius MPG & kWh - HWFET Testing
0102030405060708090
100110120130140150160170180
10 21 31 41 51 62 72 82 92 103 113 123 133 144 154
MPG
0.00.51.01.52.02.53.03.54.04.55.05.56.06.57.07.58.08.59.0
Each Bar - 1 HWFET Test Cycle, Labeled by Cumulative Miles
kWh
MPG per FWHET Test Cumulative MPG Cumulative AC kWh
10
• 9 kWh Valence (Li) pack only (AC kWh)EnergyCS Prius – UDDS Fuel Use
EnergyCS PHEV Prius MPG & kWh - UDDS Testing
0
1020
30
4050
60
7080
90
100110
120
130140
150
160170
180
7 15 22 30 37 45 52 60 67 75 82 90 97 105 112 120 127 135 142 150
Each Bar = 1 UDDS Test Cycle. Labeled by Cumulative Miles
MP
G
0
0.51
1.5
22.5
3
3.54
4.5
55.5
6
6.57
7.5
88.5
9
kWh
Drive Cycle MPG Cumulative AC kWh Cumulative MPG
11
• 9 kWh Valence (Li) pack only (AC kWh)EnergyCS Prius – HWFETS Fuel Use
EnergyCS PHEV Prius MPG & kWh - HWFET Testing
0
1020
3040
50
6070
8090
100
110120
130
140150
160170
180
10 21 31 41 51 62 72 82 92 103 113 123 133 144 154
Each Bar = 1 HWFET Test Cycle. Labeled by Cumulative Miles
MPG
0
0.51
1.52
2.5
33.5
44.5
5
5.56
6.5
77.5
88.5
9
kWh
Drive Cycle MPG Cumulative AC kWh Cumulative MPG
12
Hymotion Escape – UDDS Fuel Use• 8.5 kWh A123Systems (Li) and Escape packs (AC kWh)
Hymotion PHEV Escape MPG & kWh - UDDS Testing
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
7 15 22 30 37 45 52 60 67 75 82 90 97 105 112 120 127 135 142
Each Bar = 1 UDDS Test Cycle. Labeled by Cumulative Miles
MP
G
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
kWh
Drive Cycle Fuel Economy Cumulative AC kWhrs Cumulative Fuel Economy
13
Hymotion Escape – HWFETS Fuel Use• 8.5 kWh A123Systems (Li) and Escape packs (AC kWh)
Hymotion PHEV Escape MPG & kWh - HWFET Testing
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
10 21 31 41 51 62 72 82 92 103 113 123 133 144 154
Each Bar = 1 HWFET Test Cycle. Labeled by Cumulative Miles
MPG
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
kWh
Drive Cycle Fuel Economy Cumulative AC kWhrs Cumulative Fuel Economy
14
• 12 kWh Electrovaya (Li) and Escape packs (AC kWh)Electrovaya Escape – UDDS Fuel Use
Electrovaya PHEV Escape MPG & kWh - UDDS Testing
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
7 15 22 30 37 45 52 60 67 75 82 90 97 105 112 120 127 135 142
Each Bar = 1 UDDS Test Cycle. Labeled by Cumulative Miles
MPG
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
kWh
MPG per UDDS Test Cumulative AC kWh Cumulative UDDS MPG
15
• 12 kWh Electrovaya (Li) and Escape packs – (AC kWh)Electrovaya Escape – HWFETS Fuel Use
Electrovaya PHEV Escape MPG & kWh - HWFET Testing
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
37 42 41 35 33 36 36 36 36 36 36 36 36 36 36
Each Bar = 1 HWFET Test Cycle. Labeled by Cumulative Miles
MPG
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
kWh
MPG per HWFET Cumulative AC kWh Cumulative HWFET MPG
16
Renault Kangoo Test Results• First OEM series PHEV with 9.6 kWh (usable) Saft NiCad
pack and 650cc gasoline engine
40.90.042Battery and Gas Hot HWFETS
0.271Battery Only @ Constant 45 mpg
0.110
0.144
0.155
0.268
AC kWh per Mile
39.4Battery and Gas Hot UDDS
42.3Battery and Gas Cold UDDS
Battery Only - HWFETS
Battery Only – UDDS
Miles per GallonTest Cycle
17
PHEV Accelerated Testing• Accelerated testing in Phoenix over 5,440 miles• GPS units track distance, average and maximum speeds
188.357%43%Average5,4401621,3443,1002,340Total
11%2%60031218220011%4%6006128210012%5%640812628011%6%6001012426011%9%6001512404011%9%6001512224011%9%6001512044011%19%600308112011%37%6006040110(%)(%)(mi)(N)(hr)(10 mi)(10 mi)(mi)
MilesRepsTotalRepsChargeHighwayUrbanCycle
18
Hymotion Prius – Accelerated Testing
101.1 6.0584.1060015120440
127.24.81
79.5 Weighted Average5,440167140431002540Total54.811.0215.060031218220073.28.4335.986006128210058.311.3643.99640812628068.98.9855.336001012426073.18.5479.8260015124040
106.95.7887.2260015122240
115.9 5.37122.026003081120136.336006040110
MPGGalsAC kWh(mi)(N)(hr)(10 mi)(10 mi)(mi)GasolineElectricityTotalRepsChargeHighwayUrbanCycle
Each total distance slightly greater than 600 and 640 miles. HEV version = 44 mpg
19
EnergyCS Prius – Accelerated Testing
42.714.2925.00600*15120440
128.14.78115.586006040110
Weighted Average484014798425002340Total57.810.4612.9860031218220070.88.8122.676006128210065.810.0939.046408126280
103.75.9065.006001012426055.511.3632.44600*5124040
Testing600*5122240
77.9 7.95 86.216003081120
MPGGalskWh(mi)(N)(hr)(10 mi)(10 mi)(mi)
GasolineElectricityTotalRepsChargeHighwayUrbanCycle
*Software updated and cells replaced. Rerun. Each total distance slightly greater than 600 miles. HEV version = 44 mpg
20
* Testing ended when gasoline engine and inverter failed. Each total distance slightly greater than 600 miles.
Renault Kangoo – Accelerated Testing
Deleted*Deleted*
44.6257.9628.6033.2235.18
131.96
359.60
AC kWh
Electricity
05.62005120440
0
3,04012387614801560Total60031218220060061282100
38.616.614.4640812628045.113.310.460010124260
07.0200512404006.02005122240
04.66003081120
1.76006040110
MPGGalsMi/kWh(mi)(N)(hr)(10 mi)(10 mi)(mi)
GasolineTotalRepsChargeHighwayUrbanCycle
21
Hymotion Escape – Accelerated Testing
38.715.99
45.3
41.114.9157.5160015120440
Weighted Average5440162134431002340Total33.517.7226.0960031218220039.815.6958.646006128210041.316.0577.696408126280
13.7097.186001012426051.511.92114.1460015124040
76.2960015122240
45.713.51163.296003081120Testing6006040110
MPGGalsAC kWh(mi)(N)(hr)(10 mi)(10 mi)(mi)GasolineElectricityTotalRepsChargeHighwayUrbanCycle
Each total distance slightly greater than 600 miles. HEV version = 27 mpg
22
Electrovaya Escape – Accelerated Testing
43.137.316.4271.360015120440
Weighted Average5440162134431002340Total600312182200
29.221.1720.856006128210040.816.3042.72640812628037.316.6444.796001012426029.820.7355.8460015124040
14.3469.860015122240
60030811206006040110
MPGGalsAC kWh(mi)(N)(hr)(10 mi)(10 mi)(mi)GasolineElectricityTotalRepsChargeHighwayUrbanCycle
Each total distance slightly greater than 600 miles. HEV version = 27 mpg
23
Hymotion Prius – Fuel Costs
Hymotion PHEV Prius UDDS & HWFEDS Fuel Cost per Mile
$0.000
$0.005$0.010
$0.015
$0.020$0.025
$0.030$0.035
$0.040
$0.045$0.050
$0.055
$0.060$0.065
$0.070
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Each data point labeled by HWFEDS and UDDS tests, uneven miles. Gas $4.00 gallon & kWh $0.10
Fuel
Cos
t per
Mile
HYM UDDS $ per Mile Gas
HYM UDDS $ per Mile kWh
HYM HWY $ per Mile Gas
HYM HWY $ per Mile kWh
HYM Prius UDDS Combined $$ PER MILE
HYM Prius HWY Combined $$ PER MILE
24
PHEV Vs. HEV and ICE Fuel Costs per MilePHEVs, HEV & ICEs - Fuel Costs per Mile
$0.03$0.04$0.05$0.06$0.07$0.08$0.09$0.10$0.11$0.12$0.13$0.14$0.15$0.16$0.17$0.18$0.19$0.20$0.21
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20Each data point labeled by HWFEDS and UDDS Tests, Uneven Miles. Gas $4.00 gallon & kWh $0.10
Fuel
Cos
t per
Mile
ECS UDDS Combined $$ PER MILEECS HWY Combined $$ PER MILEHYM Prius UDDS Combined $$ PER MILEHYM Prius HWY Combined $$ PER MILEHEV Prius 45 MPGICE Gas 30 MPGICE Gas 20 MPGECS Prius Accelerated TestingHYM Escape UDDS Combined $$ PER MILEHYM Escape HWY Combined $$ PER MILEHYM Prius Accelerated TestingEltro UDDS Combined $$ PER MILEEltro HWY Combined $$ PER MILE
25
Onroad Demonstration and Data Collection Partners• ~75 Testing partners in the U.S. and Canada, including:
– 36 Electric utilities (some via NRECA)– 6 City governments– 2 County governments– 2 State governments– 8 Universities and colleges– 2 Clean air agencies– 7 Private companies and advocacy organizations– 3 Governments of Canadian provinces– 2 Sea ports and U.S. military organizations– 2 PHEV conversion companies
26
14+13? - Canada
2
16+211
11
6
11+2
2
6
1+3
37
3
2 5+20?
195 w/data loggers32 adding CY0833? In discussion127 Total end of CY08
PHEVs and Demonstration Locations
1
1
27
Hymotion Joint Data Collection• Kvaser data loggers installed 50 PHEVs North America• Onboard data includes vehicle performance, fuel use,
and charging and driving profiles• Participants include electric utilities, water agencies,
universities, county and provincial governments:– Northeast: Vermont, New Hampshire, New York – East / South East: Toronto, Virginia, South Carolina,
North Carolina, Kentucky, Florida – North / Central: Wisconsin, North Dakota, Indiana,
Manitoba– Southwest: Arizona, Texas– West Coast: California, Oregon
• Started 2007
28
Single Hymotion Prius Charging Profiles• 3 months, 2212 miles, 35 charges
Time at start of charging
0
2
4
6
8
10
12
14
0 - <
2
2 - <
4
4 - <
6
6 - <
8
8 - <
10
10 -
<12
12 -
<14
14 -
<16
16 -
<18
18 -
<20
20 -
<22
22 -
<24
Time
# of
cha
rgin
g ev
ents
AC energy in per charging event (kWh)
0123456789
0.5 1
1.5 2
2.5 3
3.5 4
4.5 5
Mor
e
Kilowatt Hours
# of
cha
rgin
g ev
ents
Length of charging time per charging event
0
2
4
6
8
10
12
1 2 3 4 5 6 7 8 9 10 MoreHours
# of
cha
rgin
g ev
ents
29
Single Hymotion Prius Charging Profiles
Plug-in battery SOC after charging
0
5
10
15
20
25
30
10 20 30 40 50 60 70 80 90 100SOC%
# of
cha
rgin
g ev
ents
Number of trips since last charging event
0
2
4
6
8
10
0 1 2 3 4 5 6 7 8 9 10 MoreTrips since last charging event
Freq
uenc
y
Plug-in battery SOC prior to charging
0
2
4
6
8
10
12
10 20 30 40 50 60 70 80 90 100SOC %
# of
cha
rgin
g ev
ents
Total distance since last charging event (mi)
0
2
4
6
8
10
12
0 10 20 30 40 50 60 70 80 90 100 110 120MoreMiles
# of
cha
rgin
g ev
ents
• 3 months, 2212 miles, 35 charges
30
26 Hymotion Prius - January thru May 2008• Below averages do NOT tell the whole PHEV energy-
use potential – see following slides
48
40
49
59
Miles per Gallon
42,000
16,059
11,121
14,820
Distance Traveled (Miles)
1,358Charge Sustaining (CS)
4,835
404
3,073
Number of Trips
All trips combined
Mixed CD / CS
Charge Depleting (CD)
Charge / Operating Mode
31
13 Hymotion Prius in May 2008 - MPG• Below averages do NOT tell the whole PHEV energy
use potential – see following slides
55.9
40.2
52.1
72.0
MPG
8.1
7.0
0.9
10.6
27.5
5.3
Average Trip Distance (miles)
6,291
6,417
127
1,411
1,840
3,040
Total Distance (Miles)
775CD, CS, CD/CS results (excludes EV results)
133Charge Sustaining (CS)
912
137
67
575
Number of Trips
Total
0.236Electric vehicle only (EV)
0.050Mixed CD / CS
0.138Charge Depleting (CD)
DC kWh per MileCharge / Operating Mode
32
13 Hymotion Prius MPG Vs. Speed
Trip Fuel Economy vs. Trip Average Speed - May 2008
0
50
100
150
200
250
300
0 10 20 30 40 50 60 70 80 90
Trip Average Speed (mph)
Trip
Fue
l Eco
nom
y (m
pg)
CD tripsCD/CS tripsCS trips
33
13 Hymotion Prius MPG Vs. Distance
Trip Fuel Economy vs. Trip Distance
0
50
100
150
200
250
300
0 5 10 15 20 25 30 35 40 45 50
Trip Distance (mi)
Trip
Fue
l Eco
nom
y (m
pg)
CD tripsCD/CS tripsCS trips
34
13 Hymotion Prius and Aggressive DrivingMPG vs. Trip Aggressiveness (Percent of time above the 40% accelerator pedal position)
0%
10%
20%
30%
40%
50%
60%
0 25 50 75 100 125 150 175 200 225 250 275 300
Trip Fuel Economy (mpg)
Agg
ress
iven
ess
Fact
or
CD tripsCD/CS tripsCS tripsLog. (CD trips)Log. (CD/CS trips)
35
NYSERDA Testing Partnership
OngoingOngoingHybridsPlus Escape
OngoingOngoingElectovaya Escape
OngoingCompletedHymotion Escape
CompletedCompletedHymotion Prius
Near completion, restartedCompletedEnergyCS Prius
Accelerated TestingBaseline TestingModel
• AVTA is testing New York State Energy Research and Development Agency’s PHEV conversions, stated 2007
• Fleet testing of ~20 PHEVs later CY08
36
EnergyCS Prius Data Collection• Provided AVTA onboard data for 12 vehicles operating
in fleets in the U.S. and Canada • Going forward, EnergyCS is using lithium batteries from
various manufacturers• ~ 30 vehicles deployed (~15 North America and ~15
Europe)
37
Seattle Area Demonstration • 13 Hymotion Prius operations in partnership with:
– City of Seattle (4)– King County (4)– Port of Seattle (2)– Puget Sound Clean Air Agency (3)– Started 4/2008, nine vehicles converted to date,
remainder October 2008• City of Seattle lead time-of-day charging demonstration
on above 13 Seattle area PHEVs. Includes INL battery impact analysis. Uses V2Green wireless charging control
• These and all future demonstrations are using V2Green onboard data loggers with cellular data transfer and GPS
38
Tacoma Power Demonstration • Vehicle demonstration using
– 2 Manzanita lead acid Prius, 1st quarter 2008– 2 Hymotion Prius adding late 2008
• Charging infrastructure study – After 4 PHEVs in operation, collect data on one
section of administration building (800 amp, 480 volt, 3 phase load) and PHEV charging infrastructure
– Document demand and energy profiles of PHEV charging as portion of facility profiles
– WiFi local energy meter (LEM) data collection system
39
Fleet Demonstration Partners – cont’d• Washington State-wide, Port of Chelan leading, with 14
Hymotion Prius with:– Benton County PUD, Chelan County Public Works,
City of Wenatchee, Douglas County PUD, Energy Northwest, Green IT Alliance, McKinstry, Port of Chelan, University of Washington, Walla Walla Community College and Wenatchee Valley College
– Started 4/2008, 1 converted to date, more Oct. 2008• University of California Davis, with 13 Hymotion Prius
– Up to 70 AAA of California public drivers will each operate a vehicle for ~2 months
– First study of public use of PHEVs, charging practices and locations, started April 2008
– 13 vehicles recently completed conversions
40
Fleet Demonstration Partners – cont’d• National Rural Electric Cooperative Association
– Total of ten Prius and Escape PHEVs from Hymotion, EnergyCS, and Hybrids Plus operated by rural electric coop utilities, 6 converted to date, started 2007
– Includes: Jackson Electric Membership Coop (GA), Salem Electric (OR), Four County Electric Membership Corp. (NC), Central Electric Power Coop (SC), Great River Electric (MN), and Buckeye Rural Electric Coop (OH)
• Hawaii, with 6 Hymotion Prius on Maui and Oahu – State of Hawaii, University of Hawaii, Hawaiian
Electric Company, Maui Electric Company, Maui County, U.S. Air Force
– Planned start 11/2008
41
Other PHEV Testing• Hymotion/A123Systems V2 Prius battery hot weather
vehicle/battery testing, summer 2008• PHEV charging studies at three commercial facilities
(Tacoma Power is one). Started 5/2008• Bidirectional vehicle-to-grid (V2G) charging study with
electric utilities participating. Fall 2008– 6 kW and 20 kW levels, using two lithium battery
PHEVs, V2Green cellular charging control, documenting infrastructure requirements and costs
• Conduct vehicle/battery testing on PHEVs when received via DOE’s OEM TADA PHEV solicitation
• Will consider other suitable PHEV conversions for vehicle/battery testing
42
Charging Infrastructure• National Electric Code requires
– Dedicated branch circuit– GFCI (ground fault circuit interrupt)– “EV” extension cord– Unique connector “plug”
• NEC being updated
43
PHEV Market Status - Converters• Hymotion: ~125 Prius ($9995) and 5 Escapes
– Prius only battery production ramp-up now, replacing all 67 Version 1 batteries. Recall most Escapes
– Prius crash-tested and obtaining CARB certification– Conversions and warranty work in Boston, D.C., L.A.,
Minneapolis, San Francisco and Seattle• Hybrids Plus: ~35 Prius and Escapes, ($21,600 to
$36,150). Some operational issues• EnergyCS: ~30 Prius (~$40,000). Some operational
issues with early batteries• Cal Cars: 8 Pius, believed to be all lead acid• Green Car Company: 3(?) Manzanita lead acid Prius
conversions ($12,000). Some operational issues. Doing Hymotion conversions
• Electrovaya: 2(?) Escapes. Some operational issues• Various single conversion “companies”
44
AVTA Webpage Use and Gasoline CostsINL WWW Visitors & Gasoline Costs
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
May
'02
June
July
Aug
Sept
Oct
Nov
Dec
'02
Jan
'03
Feb
Mar
chAp
rilM
ay
June
July
Aug
Sept
Oct
Nov
Dec
'03
Jan
'04
Feb
Mar
chAp
rilM
ayJu
neJu
lyAu
gSe
ptO
ctN
ovD
ec '0
4Ja
n '0
5Fe
bM
arch
April
May
June
July
Aug
Sept
Oct
Nov
Dec
'05
Jan
'06
Feb
Mar
chAp
rilM
ayJu
neJu
lyAu
gSe
ptO
ctN
ov
Dec
'06
Jan
'07
Feb
Mar
chAp
rilM
ayJu
neJu
lyAu
gSe
ptO
ctN
ovD
ec '0
7Ja
n '0
8Fe
bM
arch
April
May
June
July
Aug
Num
ber o
f Mon
thly
Vis
itors
$1.25
$1.50
$1.75
$2.00
$2.25
$2.50
$2.75
$3.00
$3.25
$3.50
$3.75
$4.00
$4.25
All G
rade
s G
asol
ine
Cos
ts -
End
of M
onth
Visitors (left axis)
Gasoline Cost (right axis)
Linear (Gasoline Cost (right axis) )
Linear (Visitors (left axis))