Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
California Air Resources BoardChairman’s Air Pollution Seminar Series
June 12, 2002
Overview and Results of a Statewide Survey of Vehicle Registration Status in California
Theodore Younglove, Tom Durbin, Carrie Malcolm, and Matt Smith
Bourns College of EngineeringCenter for Environmental Research and Technology University of California Riverside, CA 92521-0434
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Project Sponsors:
California Air Resources Board
South Coast Air Quality Management District
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Acknowledgments:California Air Resources Board
Alberto Ayala, Mark Carlock, Sandee Kidd
Department of Consumer Affairs, Bureau of Automotive Repair
David Amlin, Mark Duewel, Kathy Runkle, and Greg Sweet
Data Collection
Hugo Galdamez, John Gaskins, Shayna Golbaf, Beth Lee, Don Pacocha,
Alison Rowlen, Judy Swineford, and Sylvester Wheeler
Data Entry
Jennifer Anderson, Warren Katzenstein, Lindsey Miller, Shelly Miller,
Andrea Ruiz, Jessica Walters, and Ryan Wicks
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Site Selection
• Data collected in all 58 counties in California, proportional to
county population.
• Minimum county sample size set to 200. Actual sampling was less
in the smallest population counties.
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Site Selection
• Data collected at randomly selected zip codes within each county.
• Sample size proportional to zip code population.
• Random parking lots throughout the zip code.
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Parking Lot Selection
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Data Capture
• Data collected by cruising parking lots and photographing vehicles in the lot.
• Data collected at 3 to 5 mph without stopping.
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Data Capture
• Unregistered Vehicle Survey data collection using digital still
cameras.
– Toshiba M4 digital camera selected for rapid refresh rate (0.8
seconds between pictures).
• Data stored on Flash Media for download to PC for data entry.
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Data Capture
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Data Capture
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Data Capture
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Data Capture
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Data Capture: ZIP Code Centroids
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Siskiyou
DelNorte
Modoc
Humboldt
Trinity ShastaLassen
TehamaPlumas
ButteMendocinoGlenn Sierra
YubaLake
NevadaColusa
PlacerSutter
El DoradoYolo
AlpineNapaSonoma
Sacramento
Mono
Amador
CalaverasTuolumne
MarinSan
Joaquin
Solano
ContraCosta
StanislausAlameda
Mariposa
San Francisco
Madera
SanMateo
Merced
Fresno
SantaClara
Inyo
SantaCruz
SanBenito
Monterey Tulare
Kings
Kern
San Bernardino
San LuisObispo
Ventura
Riverside
SantaBarbara
Orange
San Diego
LosAngeles
Imperial
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
License Plate Obstructions - Non-Random
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
License Plate Obstructions - Random
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Public Interactions
95% Oblivious 4.9% Notice, but don’t care
0.1% Notice, but not happy
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Data Analysis
• Two methods of registration classification:
– Observed data.
–Vehicle license plates were characterized by registered,
unregistered, dealer, front, no plate, out of state, unknown
state, and unknown based on stickers observed on the plate.
– DMV comparisons.
–Vehicle license plate data will be submitted to the DMV to
obtain official registration status.
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Data Analysis
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Average County Non-Registration Rate 3.5%
Siskiyou
DelNorte
Modoc
Humboldt
Trinity ShastaLassen
TehamaPlumas
ButteMendocinoGlenn Sierra
YubaLake
NevadaColusa
PlacerSutter
El DoradoYolo
AlpineNapaSonoma
Sacramento
Mono
Amador
CalaverasTuolumne
MarinSan
Joaquin
Solano
ContraCosta
StanislausAlameda
Mariposa
San Francisco
Madera
SanMateo
Merced
Fresno
SantaClara
Inyo
SantaCruz
SanBenito
Monterey Tulare
Kings
Kern
San Bernardino
San LuisObispo
Ventura
Riverside
SantaBarbara
Orange
San Diego
LosAngeles
Imperial
Siskiyou
DelNorte
Modoc
Humboldt
Trinity ShastaLassen
TehamaPlumas
ButteMendocinoGlenn Sierra
YubaLake
NevadaColusa
PlacerSutter
El DoradoYolo
AlpineNapaSonoma
Sacramento
Mono
Amador
CalaverasTuolumne
MarinSan
Joaquin
Solano
ContraCosta
StanislausAlameda
Mariposa
San Francisco
Madera
SanMateo
Merced
Fresno
SantaClara
Inyo
SantaCruz
SanBenito
Monterey Tulare
Kings
Kern
San Bernardino
San LuisObispo
Ventura
Riverside
SantaBarbara
Orange
San Diego
LosAngeles
Imperial
Percent Unregistered Vehicles0 - 1 1 - 22 - 33 - 44 - 55 - 66 - 7
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
County Non-Registration Rate: All counties
0
5
10
15
20
0-1 1-2 2-3 3-4 4-5 5-6 >6
Percent Unregistered Vehicles
Num
ber o
fC
ount
ies
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
County Non-Registration Rate: Counties with population >300,000
02
4
68
10
0-1 1-2 2-3 3-4 4-5 >5
Percent Unregistered Vehicles
Num
ber
ofC
ount
ies
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Non-Registration Rate by length of time unregistered (overall 3.38%)–Instantaneous - <3 months–Long Term - 3 months to 2 years–Chronic - > 2 years
0.95
2.41
0.030.0 0.5 1.0 1.5 2.0 2.5 3.0
Instanteous Long Term Chronic
Unregistration Status
Percent of Total
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Results:Riverside County: Percent unregistered vehicles by zip code
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Results:Riverside County: Percent of vehicles > 3 months unregistered
0
5
10
15
1979
1984
1986
1989
1991
1994
1996
1998
Model Year
Perc
ent
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Results:Riverside County: Number of vehicles > 3 months unregistered
0
2
4
6
8
1979
1984
1986
1989
1991
1994
1996
1998
Model Year
Num
ber
of V
ehicl
es
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Results:Demographic Analysis: County Median Household Income
2 29.383 14.692 9.157 .000455 88.246 1.60457 117.629
DF Sum of Squares Mean Square F-Value P-ValueRegressionResidualTotal
ANOVA Table% Unreg vs. Median HI ($)
-9.308 3.036 -9.308 -3.066 .0034.001 1.879E-4 3.668 3.744 .0004
-9.640E-9 2.778E-9 -3.400 -3.470 .0010
Coefficient Std. Error Std. Coeff. t-Value P-ValueInterceptMedian HI ($)Median HI ($)^2
Regression Coefficients% Unreg vs. Median HI ($)
-1
0
1
2
3
4
5
6
7
% U
nreg
15000 20000 25000 30000 35000 40000 45000 50000Median HI ($)
Y = -9.308 + .001 * X - 9.64E-9 * X^2; R^2 = .25
Regression Plot
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Results:Demographic Analysis: County Population
1 5.722 5.722 2.864 .096256 111.907 1.99857 117.629
DF Sum of Squares Mean Square F-Value P-ValueRegressionResidualTotal
ANOVA Table% Unreg vs. population
2.517 .202 2.517 12.431 <.00012.344E-7 1.385E-7 .221 1.692 .0962
Coefficient Std. Error Std. Coeff. t-Value P-ValueInterceptpopulation
Regression Coefficients% Unreg vs. population
-1
0
1
2
3
4
5
6
7
% U
nreg
-1000000 1000000 3000000 5000000 7000000 9000000population
Y = 2.517 + 2.344E-7 * X; R^2 = .049
Regression Plot
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Results:Demographic Analysis: County Percent Home Ownership
1 2.482 2.482 1.207 .276656 115.147 2.05657 117.629
DF Sum of Squares Mean Square F-Value P-ValueRegressionResidualTotal
ANOVA Table% Unreg vs. Owner %
4.436 1.633 4.436 2.716 .0088-.028 .026 -.145 -1.099 .2766
Coefficient Std. Error Std. Coeff. t-Value P-ValueInterceptOw ner %
Regression Coefficients% Unreg vs. Owner %
-1
0
1
2
3
4
5
6
7
% U
nreg
30 35 40 45 50 55 60 65 70 75 80Ow ner %
Y = 4.436 - .028 * X; R^2 = .021
Regression Plot
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Siskiyou
DelNorte
Modoc
Humboldt
Trinity ShastaLassen
TehamaPlumas
ButteMendocinoGlenn Sierra
YubaLake
NevadaColusa
PlacerSutter
El DoradoYolo
AlpineNapaSonoma
Sacramento
Mono
Amador
CalaverasTuolumne
MarinSan
Joaquin
Solano
ContraCosta
StanislausAlameda
Mariposa
San Francisco
Madera
SanMateo
Merced
Fresno
SantaClara
Inyo
SantaCruz
SanBenito
Monterey Tulare
Kings
Kern
San Bernardino
San LuisObispo
Ventura
Riverside
SantaBarbara
Orange
San Diego
LosAngeles
Imperial
Percent Out of State Vehicles0 - 12 - 55 - 1010 - 1515 - 20>20
Out of State Vehicles
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Percentage of missed vehicles
Imperial
LosAngeles
San Diego
Orange
SantaBarbara
Riverside
Ventura
San LuisObispo
San Bernardino
Kern
Kings
TulareMonterey
SanBenito
SantaCruz
Inyo
SantaClara
Fresno
Merced
SanMateo
Madera
San Francisco
MariposaAlameda
Stanislaus
ContraCosta
Solano
SanJoaquin
MarinTuolumne
Calaveras
Amador
Mono
Sacramento
Sonoma Napa Alpine
Yolo El DoradoSutter
PlacerColusa
NevadaLake
Yuba
SierraGlennMendocino Butte
PlumasTehama
LassenShastaTrinity
Humboldt
Modoc
DelNorte
Siskiyou
Percent Missed Vehicles0 - 22 - 55 - 1010 - 2020 - 4040 - 65
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Results:Riverside County: Fleet composition
0
100
200
300
400
1972
1975
1978
1981
1984
1987
1990
1993
1996
1999
Model Year
Num
ber
of V
ehicl
es
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Results:Riverside County: Emission controls
TWC EGR Both Neither Unknown TotalRegistered 342 80 1803 18 22 2265
Unregistered 14 5 93 1 3 116
020406080
100
% TWC % EGR % Both % None
Emission Control
Perc
ent o
f Fle
et
Registered
Unregistered
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Results:Fleet Composition: DMV, On-Road, and Parking Lot
L o s A n g e l e s C o u n t y
0
2 0
4 0
6 0
8 0
1 0 0
M o d e l Y e a r
Perc
ent D M V
SE L E V
U n r e g
O r a n g e C o u n t y
0
2 0
4 0
6 0
8 0
1 0 0
M o de l Y e a r
Perc
ent D M V
SE L E V
U n re g
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Results:Smog Check Analysis; 64,892 license plates having Smog Check and observed registration status.
Field Number Pass Failed Gross Polluter Tampered Aborted UnknownStatus # % # % # % # % # % # %
Registered 51974 50423 97 682 1.3 250 0.48 25 0.1 391 0.8 203 0.4Instantaneous 1449 1385 95.6 30 2.1 13 0.90 2 0.1 12 0.8 7 0.5Long Term 601 549 91.4 18 3 19 3.16 2 0.3 10 1.7 3 0.50
Chronic 13 11 84.6 1 7.7 1 7.69 0 0.00 0 0.00 0 0.00Front 4921 4716 95.8 91 1.9 44 0.89 4 0.1 44 0.9 22 0.5
Unknown 7387 7015 95 157 2.1 66 0.89 13 0.2 83 1.1 53 0.7Total 66346 64100 979 393 46 540 288
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Results:Travel Study: Origins and destination locations by zip code for 92505
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Results:Travel Study Example: Geocoded destination locations for all of Riverside County
Total Addresses 98Matched Addresses 45Unmatched Total 53
Incomplete Addresses 16
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Results:Travel Study: Average miles traveled in Riverside County by model year
02468
1012
1972
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
Model Year
Ave
rage
Mile
s
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Results:Travel Study: Average miles traveled in Riverside County by business type
02468
10
Ban
k
Bus
ines
s
Educ
atio
n
Food
Gro
cery
Mal
l
Med
ical
Min
i Mal
l
Rec
reat
iona
l
Ret
ail
Ave
rage
Mile
s
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Conclusions:• Unregistered vehicles typically older that the general vehicle population.
• Higher proportions of out of state vehicles on the road in:– Counties near the state border.– Zip codes and counties with tourist attractions.
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Future Work:• Comparison of observed registration to DMV registration.
• Comparison of Smog Check results for registered and unregistered vehicles.
• In-depth travel study:– Geocode in ArcView all origins (home address of registered vehicle) and destinations (address of data collection sites).– Determine distance traveled by model year, business type and characterize cross county travel.
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
Samples of Captured Vehicles
Center for Environmental Research and Technology
University of California, RiversideBourns College of Engineering
California - Summer 2000