Carbon Emissions and
Climate Change
A Study of Attitudes and their
Relationship with Travel Behavior
Prepared for:
TRB National Transportation Planning
Applications Conference
3/18/2016
Research Questions
Do drivers know what vehicle carbon emissions are?
What are driver’s opinions about a link between carbon
emissions from vehicles and climate change?
Are drivers likely to change travel behavior to reduce
carbon emissions?
Do drivers support policies such as using toll revenue to
implement carbon emission reduction programs?
2
Context
Sources of US GHG Emissions, MMT CDE, by Sector, 2007
Industrial
2,610
35%
Transportation
2,036
28%
US Transport Sector, CO2 Emissions, 1947-2007
2,500
Commercial
1,355
19%
2,000
~2% CAGR
MMT CO2
Residential
1,281
18%
1,500
1,000
500
06
20
03
20
97
00
20
19
94
19
88
85
91
19
19
19
82
76
79
19
19
19
73
19
67
70
19
19
64
19
58
61
19
19
55
19
52
19
19
49
-
Y ear
Source: Emissions of Greenhouse Gases in the United States 2007 (DOE/EIA-0573(2007)), 3 Dec. 2008
3
Context
Source: Global Warming on the Road: The Climate Impact of America’s Automobiles Environmental Defense 2006
4
Policy
 “To have the greatest chance to slow and perhaps even reverse the slide
toward calamitous climate change, we need to mobilize the widest
possible public support for effective actions. And to do this effectively,
we need to understand the bases of public attitudes and behavior.”
Source: PUBLIC ATTITUDES AND BEHAVIOR ABOUT CLIMATE CHANGE: What Shapes Them and How to Influence
Them, Martin Patchen, 2006
5
Attitude Towards Climate Change
Belief is most strongly held by:
•Urban residents
•Younger people
•More educated people
Source: A Deeper Partisan Divide Over Global Warming The Pew Research Center for the People and the Press, 2008
6
Behavioral Attitude Towards Climate Change
“There is consistent evidence that people’s willingness to take
specific environmentally-helpful actions or support specific proenvironmental policies declines as the amount of sacrifice
connected to the action or policy increases.”
“A study of Americans also found that people were much more
likely to support policies that had no clear costs to them
personally.”
 90 % believe the U.S. should reduce GHG emissions
 77% support CO2 regulations
 54% support a 5% gas guzzler tax on vehicles < 25mpg
 17% support a 60 cent/gallon gas tax to encourage people to drive less and
reduce emissions.
Source: PUBLIC ATTITUDES AND BEHAVIOR ABOUT CLIMATE CHANGE: What Shapes Them and How to Influence
Them, Martin Patchen, 2006
7
Attitudinal Segmentation of the UK Populations
‘Believe but busy’ believe climate change is happening but feel that
they are unable to act because they have other priorities
‘Contributors’ are prepared to take action because they believe that
small actions by many people will have an impact on climate change.
‘Deniers’ are skeptical that human activity impacts climate change. May
be motivated by cost and time saving arguments but not by
environmental considerations.
‘Ineffectuals’, believe that climate change is happening but do not
believe that their actions will make a difference.
‘Aspirationals’ are younger people, who are relatively well educated
about climate change but who have lifestyle aspirations that deter them
from taking actions that will reduce their carbon consumption.
Source: Exploring public attitudes to climate change and travel choices: deliberative research (King et al, 2009)
8
Project Locations
Project
Responses
Austin
1852
Chicago
1976
Dallas
1619
Dothan
430
Norfolk
2340
Total
8217
Chicago, IL
July 2008
Norfolk, VA
May 2009
Dallas, TX
December 2008
Austin, TX
May 2008
Dothan, AL
June 2008
9
Survey Methodology

Computer-based stated preference surveys

Designed to estimate the values of travel
time savings (VOTs) of potential users of
road pricing projects

Multi-method sampling approach




In-person intercept at activity sites near the study corridor
Hand-out/mail-out postcard invitations
Employer emails
Online sample providers
10
General Questionnaire Outline
RP Trip
Characteristics
Stated
Preference
Debrief and
Attitudes
 Questions describing respondent’s recent trip in the corridor
 E.g. purpose, time of day, origin, destination, etc.
 Stated preference trade-off questions presenting various travel
alternatives under different time and cost conditions
 Toll attitude questions
 Emissions attitude questions
 Basic individual and household-level demographic information,
Demographics
such as gender, age, employment, household size, household
vehicles, annual household income
11
Attitude Statements

Three toll attitude statements:
1. I will use a toll route if the tolls are reasonable and I
save time.
2. I support using tolls to pay for highway improvements
that relieve congestion.
3. I can generally afford to pay tolls.

Five climate/emissions attitude
statements:
1. I understand what vehicle carbon emissions are.
2. Carbon emissions from my vehicle contribute to climate
change.
3. I am willing to carpool or take public transit more
frequently to reduce carbon emissions from my vehicle.
4. I am willing to pay higher tolls if they are used to reduce
air pollution and carbon emissions.
5. I support using tolls to pay for public transportation.

Five point scale from “strongly disagree”
to “strongly agree”
12
Attitude Analysis
 A few disclaimers:
 Preliminary work
 Stated preference samples are not necessarily population-proportional
 Not all questions included in all surveys for various reasons
 These are “add-on” questions to a stated preference survey
Attitude Statement
Austin
Chicago
Dallas
Dothan
Norfolk
N
I will use a toll route if the tolls are reasonable and I save time.
X
X
X
X
X
8217
I support using tolls to pay for highway improvements that relieve
congestion.
X
X
X
X
X
8217
I can generally afford to pay tolls.
X
--
X
X
X
6241
I understand what vehicle carbon emissions are.
X
X
X
--
--
5447
Carbon emissions from my vehicle contribute to climate change.
X
X
X
X
X
8217
I am willing to carpool or take public transit more frequently to
reduce carbon emissions from my vehicle.
X
X
X
X
X
8217
I am willing to pay higher tolls if they are used to reduce air
pollution and carbon emissions.
X
X
X
X
--
5877
I support using tolls to pay for public transportation.
X
X
X
--
X
7787
13
Overall Attitudes
I will use a toll route if the tolls
are reasonable and I save time.
Toll
Attitudes
9%
I support using tolls to pay for highway
improvements that relieve congestion.
15%
I can generally afford to pay tolls.
13%
I understand what vehicle
carbon emissions are.
6%
13%
42%
12%
14%
30%
19%
37%
17%
19%
39%
16%
43%
Strongly disagree
47%
Disagree
Neutral
Carbon emissions from my vehicle
contribute to climate change.
Emission
Attitudes
7%
10%
I am willing to carpool or take public
transit more frequently to reduce
carbon emissions from my vehicle.
9%
16%
I am willing to pay higher tolls if
they are used to reduce air
pollution and carbon emissions.
21%
I support using tolls to pay
for public transportation.
20%
0%
24%
35%
18%
25%
22%
20%
28%
26%
17%
22%
40%
Strongly agree
14%
23%
29%
60%
Agree
21%
8%
13%
80%
100%
14
Toll Attitudes
Survey Location
72%
 Higher toll acceptance in Chicago and
55%
54%
Norfolk 43%
Dothan 72%
Norfolk 43%
Dothan 68%
Chicago 65%
Chicago 88%
 Lower toll acceptance in Norfolk
Norfolk 61%
Percent Agree
Dothan
I wi l l us e a tol l route I s upport us i ng tol l s I ca n genera l l y a fford
i f the tol l s a re
to pa y for hi ghwa y
to pa y tol l s .
rea s ona bl e a nd I
i mprovements tha t
s a ve ti me.
rel i eve conges ti on.
Household Income
100%
Household Income
90%
80%
associated with toll attitudes
Percent Agree
 Household income is strongly
70%
72%
Under $25,000
60%
50%
54%
55%
$25,000–$49,999
$50,000–$99,999
40%
$100,000 or more
30%
Mean Value
20%
10%
0%
I will use a toll route I support using tolls I can generally afford
if the tolls are
to pay for highway
to pay tolls.
reasonable and I save improvements that
time.
relieve congestion.
15
Toll Attitudes
100%
 Higher toll acceptance
 Employed full-time or retired
 Less toll acceptance among students
80%
70%
Percent Agree
 Older
Respondent Age
90%
72%
16-24
60%
55%
54%
50%
25-34
35-64
40%
65 +
30%
and unemployed
Mean Value
20%
10%
 No significant differences found
0%
between other demographic variables,
including
I will use a toll route I support using tolls I can generally afford
if the tolls are
to pay for highway
to pay tolls.
reasonable and I save improvements that
time.
relieve congestion.
 Household size
 Household vehicles
100%
 Gender
Employment Status
90%
80%
Percent Agree
70%
Employed full-time
72%
Employed part-time
Self-employed
60%
54%
50%
55%
Student
Homemaker
40%
Retired
30%
Unemployed
20%
Mean Value
10%
0%
I will use a toll route
if the tolls are
reasonable and I
save time.
I support using tolls
to pay for highway
improvements that
relieve congestion.
I can generally
afford to pay tolls.
16
Emission Attitudes: Understanding Emissions
I understand what vehicle carbon emissions are.
Percent Agree
Mean Value
90%
$100,000 or more
Household
Income
$50,000–$99,999
$25,000–$49,999
Under $25,000
65 or older
Age
93%
91%
87%
83%
88%
35–64
92%
25–34
16–24
Increases slightly with income
90%
Lowest age category least likely to
understand
83%
 Very little variation across other demographic variables.
 Essentially all respondents reported having an understanding of
vehicle carbon emissions
17
Emission Attitudes: Contribute to Climate Change
Carbon emissions from my vehicle contribute to climate change.
Percent Agree
Mean Value
56%
65 or older
52%
35–64
55%
25–34
Age
62%
16–24
56%
Male
Gender
53%
Female
60%
3 + vehicles
Household
Vehicles
2 vehicles
59%
1 vehicle
58%
Full-time
56%
Part-time
55%
52%
61%
Student
52%
56%
Unemployed
64%
Austin
59%
Chicago
Dothan
Dallas
Norfolk
Students more likely to agree
54%
Homemaker
Retired
Survey
Location
Women more likely to agree
More household vehicles less likely to agree
52%
Self-employed
Employment
Status
Decreases as age increases; similar to Pew study
findings
43%
55%
Austin and Chicago more likely to agree;
Dothan and Norfolk less
51%
18
Emission Attitudes: Willing to Change Behavior
I am willing to carpool or take public transit more frequently to reduce carbon emissions from my vehicle.
Percent Agree
Mean Value
42%
$100,000 or more
38%
$50,000–$99,999
Household
Income
41%
$25,000–$49,999
44%
Under $25,000
45%
65 or older
35%
35–64
40%
25–34
Age
47%
38%
2 vehicles
Household
Vehicles
46%
40%
Full-time
44%
Part-time
38%
Self-employed
49%
Student
36%
47%
Unemployed
52%
Austin
47%
Chicago
43%
Dothan
Dallas
Norfolk
Students most willing to change behavior
41%
Homemaker
Retired
Decreases as number of household vehicles increases
42%
1 vehicle
Employment
Status
Decreases as age increases
45%
16–24
3 + vehicles
Decreases as income increases
Large differences by region
37%
31%
19
Emission Attitudes: Willingness to Pay
I am willing to pay higher tolls if they are used to reduce air pollution and carbon emissions.
Percent Agree
Mean Value
Household
Income
$100,000 or more
Household
Vehicles
30%
$25,000–$49,999
30%
Male
3 + vehicles
2 vehicles
1 vehicle
Part-time
Self-employed
Student
Homemaker
Retired
Unemployed
Almost no variation by income, compared with large
variation in willingness to pay for travel time savings
34%
28%
Female
Full-time
Employment
Status
33%
$50,000–$99,999
Under $25,000
Gender
31%
35%
Women more willing to pay to reduce emissions
27%
Decreases as number of household vehicles increases
33%
35%
29%
34%
31%
36%
30%
40%
34%
20
Emission Attitudes: Tolls for Transit
I support using tolls to pay for public transportation.
Percent Agree
Mean Value
41%
$100,000 or more
Household
Income
Household
Vehicles
48%
$50,000–$99,999
40%
$25,000–$49,999
38%
Under $25,000
37%
3 + vehicles
39%
2 vehicles
44%
49%
Austin
Survey
Location
42%
Chicago
Dallas
Norfolk
Decreases as number of household vehicles increases
42%
1 vehicle
High income households more likely to
support using tolls for transit
47%
31%
21
Latent Class Analysis
Cluster Sizes
 Latent Class Analysis was used to group respondents
Cluster4
20%
into clusters based on their responses to the toll and
emission attitude questions.
Cluster1
28%
 Probability-based classification into unknown groups
 Homogenous groups of respondents who share similar attitudes
Cluster3
25%
Cluster2
27%
Percent Agree
Attitude Statement
Mean Value
Cluster 1
Cluster 2
Cluster 3
Cluster 4
I will use a toll route if the tolls are reasonable and I save time.
72%
96%
97%
33%
54%
I support using tolls to pay for highway improvements that
relieve congestion.
54%
94%
93%
2%
14%
I can generally afford to pay tolls.
55%
72%
82%
24%
44%
I understand what vehicle carbon emissions are.*
90%
90%
98%
76%
95%
Carbon emissions from my vehicle contribute to climate change.
56%
33%
90%
15%
95%
I am willing to carpool or take public transit more frequently to
reduce carbon emissions from my vehicle.
41%
20%
71%
14%
66%
I am willing to pay higher tolls if they are used to reduce air
pollution and carbon emissions.
31%
4%
84%
0%
24%
I support using tolls to pay for public transportation.
41%
47%
88%
1%
21%
> Average
< Average
* Not used as an input variable to the latent class analysis
22
Latent Class Descriptions
 Cluster 1: “I’ll pay for anything that
benefits me directly”
 Cluster 2: “I’ll do anything to reduce
my impact”
 Willing to pay to save time.
 Willing to pay to save time.
 Can afford to pay tolls.
 Can afford to pay tolls.
 Don’t believe they are contributing to climate
 Believe they are contributing to climate change
change and don’t want to do anything about it.
 Cluster Characteristics:
 Higher than average income
and willing to pay more and change behavior to
reduce impact
 Cluster Characteristics:
 Slightly older
 Slightly higher income
 Skews male
 Fewer household vehicles
 Skews female
 Cluster 3: “ I don’t believe in climate
change or double taxation.”
 Cluster 4: “I’d like to reduce my
impact, but I can’t afford it”
 Not willing to pay to save time.
 Not willing to pay to save time.
 Can’t afford to pay tolls.
 Can’t afford to pay tolls.
 Don’t believe they are contributing to climate
 Believe they are contributing to climate change
change and don’t want to do anything about it.
 Cluster Characteristics
and willing to shift behavior, but not pay extra
 Cluster Characteristics:
 Slightly lower income
 Lower income
 More household vehicles
 Younger
 More likely to be from the Norfolk Sample
 More students
 Skews female
23
Conclusions
 Vast majority of respondents are aware that their vehicles emit carbon,
but only slightly more than half think this is contributing to climate
change. Even fewer are willing to change their behavior or pay to reduce
emissions. Support decreases as personal sacrifice increases.
 Many people are willing to pay for something that directly benefits them,
such as saving travel time, but fewer are willing to pay for something less
tangible such as emissions reduction.
 Distinct attitudinal groups exist. What is the best way to market policy
initiatives to each group?
 How do you get ~50% of the population (clusters 1 and 3) to agree that climate change is an
issue?
 How do you get them to care enough to do something about it?
 More research is needed!
24
Questions?
25