04/20/23

Carbon Emissions and Climate ChangeA Study of Attitudes and their Relationship with Travel Behavior

Prepared for:TRB National Transportation Planning Applications Conference

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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?

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Residential1,28118%

Commercial1,35519%

Industrial2,61035%

Transportation2,03628%

-

500

1,000

1,500

2,000

2,500

1949

1952

1955

1958

1961

1964

1967

1970

1973

1976

1979

1982

1985

1988

1991

1994

1997

2000

2003

2006

Year

MM

T C

O2

Context

Source: Emissions of Greenhouse Gases in the United States 2007 (DOE/EIA-0573(2007)), 3 Dec. 2008

Sources of US GHG Emissions, MMT CDE, by Sector, 2007

~2% CAGR

US Transport Sector, CO2 Emissions, 1947-2007

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Context

Source: Global Warming on the Road: The Climate Impact of America’s Automobiles Environmental Defense 2006

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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

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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

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Behavioral Attitude Towards Climate Change

“There is consistent evidence that people’s willingness to take specific environmentally-helpful actions or support specific pro-environmental 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

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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)

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Project Locations

Chicago, ILJuly 2008

Norfolk, VAMay 2009

Dothan, ALJune 2008

Dallas, TXDecember 2008

Austin, TXMay 2008

Project

Responses

Austin 1852

Chicago 1976

Dallas 1619

Dothan 430

Norfolk 2340

Total 8217

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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

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General Questionnaire Outline

RP Trip Characteristics

StatedPreference

Debrief and Attitudes

Demographics

Questions describing respondent’s recent trip in the corridorE.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 questionsEmissions attitude questions

Basic individual and household-level demographic information, such as gender, age, employment, household size, household vehicles, annual household income

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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”

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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

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9%

15%

13%

10%

16%

21%

7%

12%

14%

9%

18%

22%

17%

13%

19%

19%

6%

24%

25%

26%

22%

42%

37%

39%

43%

35%

28%

23%

29%

30%

17%

16%

47%

21%

14%

8%

13%20%

0% 20% 40% 60% 80% 100%

Strongly disagreeDisagreeNeutralAgreeStrongly agree

Overall Attitudes

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.

I understand what vehicle carbon emissions are.

Carbon emissions from my vehicle contribute to climate change.

I am willing to carpool or take public transit more frequently to reduce carbon emissions from my vehicle.

I am willing to pay higher tolls if they are used to reduce air

pollution and carbon emissions.

I support using tolls to pay for public transportation.

Toll Attitudes

Emission Attitudes

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Toll Attitudes

Higher toll acceptance in Chicago and Dothan

Lower toll acceptance in Norfolk

72%

54% 55%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

I will use a toll routeif the tolls are

reasonable and I savetime.

I support using tollsto pay for highwayimprovements thatrelieve congestion.

I can generally affordto pay tolls.

Perc

ent A

gree Under $25,000

$25,000–$49,999

$50,000–$99,999

$100,000 or more

Mean Value

Household Income

Chica

go 8

8%

Nor

folk

61%

72%

I wi l l us e a tol l routei f the tol l s a re

reas onable and Is ave ti me.

Chica

go 6

5%

Doth

an 6

8%

Nor

folk

43%

54%

I s upport us ing tol l sto pay for highwayimprovements thatrel ieve conges ti on.

Doth

an 7

2%

Nor

folk

43%

55%

I can genera l ly affordto pay tol l s .

Household income is strongly associated with toll attitudes

Household Income

Survey Location

Perc

ent

Ag

ree

16

72%

54% 55%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

I will use a toll routeif the tolls are

reasonable and I savetime.

I support using tollsto pay for highwayimprovements thatrelieve congestion.

I can generally affordto pay tolls.

Perc

ent A

gree 16-24

25-34

35-64

65 +

Mean Value

Toll Attitudes

Higher toll acceptance Older Employed full-time or retired

Less toll acceptance among students and unemployed

No significant differences found between other demographic variables, including

Household size Household vehicles Gender

72%

54% 55%

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

I will use a toll routeif the tolls are

reasonable and Isave time.

I support using tollsto pay for highwayimprovements thatrelieve congestion.

I can generallyafford to pay tolls.

Perc

ent A

gree

Employed full-time

Employed part-time

Self-employed

Student

Homemaker

Retired

Unemployed

Mean Value

Respondent Age

Employment Status

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Emission Attitudes: Understanding Emissions

I understand what vehicle carbon emissions are.

83%

87%

91%

93%

Under $25,000

$25,000–$49,999

$50,000–$99,999

$100,000 or more

83%

90%

92%

88%

16–24

25–34

35–64

65 or older

90%Mean Value

HouseholdIncome

Age

Increases slightly with income

Lowest age category least likely to understand

Very little variation across other demographic variables.Essentially all respondents reported having an

understanding of vehicle carbon emissions

Percent Agree

18

64%

59%

43%

55%

51%

Austin

Chicago

Dothan

Dallas

Norfolk

Emission Attitudes: Contribute to Climate Change

56%

62%

55%

52%

16–24

25–34

35–64

65 or older

60%

53%

Female

Male

58%

59%

52%

1 vehicle

2 vehicles

3 + vehicles

56%

55%

52%

61%

54%

52%

56%

Full-time

Part-time

Self-employed

Student

Homemaker

Retired

Unemployed

Carbon emissions from my vehicle contribute to climate change.

Age

Gender

Household Vehicles

EmploymentStatus

56%Mean Value

Decreases as age increases; similar to Pew study findings

Students more likely to agree

Women more likely to agree

More household vehicles less likely to agree

SurveyLocation

Austin and Chicago more likely to agree; Dothan and Norfolk less

Percent Agree

19

52%

47%

43%

37%

31%

Austin

Chicago

Dothan

Dallas

Norfolk

40%

44%

38%

49%

41%

36%

47%

Full-time

Part-time

Self-employed

Student

Homemaker

Retired

Unemployed

Emission Attitudes: Willing to Change Behavior

I am willing to carpool or take public transit more frequently to reduce carbon emissions from my vehicle.

HouseholdIncome

Age

EmploymentStatus

45%

44%

41%

38%

Under $25,000

$25,000–$49,999

$50,000–$99,999

$100,000 or more

47%

45%

40%

35%

16–24

25–34

35–64

65 or older

46%

42%

38%

1 vehicle

2 vehicles

3 + vehicles

42%Mean Value

Household Vehicles

Decreases as income increases

Decreases as age increases

Students most willing to change behavior

Decreases as number of household vehicles increases

Large differences by region

Percent Agree

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Emission Attitudes: Willingness to PayI am willing to pay higher tolls if they are used to reduce air pollution and carbon emissions.

HouseholdIncome

Gender

34%

30%

30%

33%

Under $25,000

$25,000–$49,999

$50,000–$99,999

$100,000 or more

35%

28%

Female

Male

35%

33%

27%

1 vehicle

2 vehicles

3 + vehicles

29%

34%

31%

36%

30%

40%

34%

Full-time

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

EmploymentStatus

31%Mean Value

Household Vehicles

Women more willing to pay to reduce emissions

Decreases as number of household vehicles increases

Percent Agree

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49%

42%

47%

31%

Austin

Chicago

Dallas

Norfolk

Emission Attitudes: Tolls for TransitI support using tolls to pay for public transportation.

37%

38%

40%

48%

Under $25,000

$25,000–$49,999

$50,000–$99,999

$100,000 or more

44%

42%

39%

1 vehicle

2 vehicles

3 + vehicles

41%Mean Value

SurveyLocation

Household Vehicles

HouseholdIncome

High income households more likely to support using tolls for transit

Decreases as number of household vehicles increases

Percent Agree

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Latent Class Analysis

Latent Class Analysis was used to group respondents into clusters based on their responses to the toll and emission attitude questions.

Probability-based classification into unknown groups Homogenous groups of respondents who share similar

attitudes

Cluster1 28%

Cluster2 27%

Cluster3 25%

Cluster4 20%

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%

Cluster Sizes

* Not used as an input variable to the latent class analysis

> Average

< Average

Percent Agree

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Latent Class Descriptions

Cluster 1: “I’ll pay for anything that benefits me directly”

Willing to pay to save time. Can afford to pay tolls. Don’t believe they are contributing to

climate change and don’t want to do anything about it.

Cluster Characteristics: Higher than average income Slightly older Skews male

Cluster 2: “I’ll do anything to reduce my impact”

Willing to pay to save time. Can afford to pay tolls. Believe they are contributing to climate

change and willing to pay more and change behavior to reduce impact

Cluster Characteristics: Slightly higher income Fewer household vehicles Skews female

Cluster 3: “ I don’t believe in climate change or double taxation.”

Not willing to pay to save time. Can’t afford to pay tolls. Don’t believe they are contributing to

climate change and don’t want to do anything about it.

Cluster Characteristics Slightly lower income More household vehicles More likely to be from the Norfolk Sample

Cluster 4: “I’d like to reduce my impact, but I can’t afford it”

Not willing to pay to save time. Can’t afford to pay tolls. Believe they are contributing to climate

change and willing to shift behavior, but not pay extra

Cluster Characteristics: Lower income Younger More students Skews female

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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!

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Questions?