Exploring Changing Travel TrendsSteven E. Polzin, Ph.D.Xuehao Chu, Ph.D.Center for Urban Transportation ResearchUniversity of South Florida

Nancy McGuckinTravel Behavior Associates

Fundamentals on Interpreting NHTS Data

“If you torture the data long enough, nature will confess.”

Ronald Coase – 1991 Nobel Prize in Economics

“If you torture the data long enough you can make it confess to anything.”

Alan Pisarski – No Nobel Prizes

Simple Recipe for Using NHTS Data

3. Blend with Statistical package or various analytical tools

Sound theory or

hypothesis

Confirm with other survey, count or field

data

Other data as

available

NHTS data1. Start with:

2. Add other data as necessary and available

4. Evaluate Results

5. Serve with good graphics and compelling story

Review MOEs (margins of error) and

MORs (measures of relevance)

Anecdotal Evidence

Growth in • Income• Knowledge

Social and Economic Interactions Create Demand for Travel

Specialization in• Employment

• Consumption

• Social Relationships

• Time Use

Growth in • Person Travel

• Commerce

• Communication

Time

1969 - FIRST NHTS Population (millions) 20315,000 households surveyedIn home interviewsPerson miles traveled (trillion) 1.40

Vehicles/100 people 52Gas /gallon $ 0. 35New house $ 15,550Income per year $ 8,550New car $ 3,270

Man Walks on Moon

Wal*Mart Incorporated

ChappaquiddickBridge Incident

Woodstock Festival

Eisenhower Passes

First Computer to Computer Message

1977 - SECOND NHTS

Apple Computer Incorporated

Department of Energy Created

Alaska Pipeline Opens

Fiber optics deployed for telephone communicationsFirst Star Wars

Released

Elvis Died?

Population (millions) 21618,000 households surveyedIn home interviewsPerson miles traveled (trillion ) 1.62

Vehicles/100 people 68Gas /gallon $ 0. 65New house $ 49,300Income per year $15,000BMW 320i $ 7,990

1983 - THIRD NHTS

Modern Minivan Introduced

Michael Jackson does Moon Walk

ARPANET officially changes to use the Internet Protocol,

creating the Internet

First mobile phones introduced to public by Motorola

Top Seller Ford Escort

McNuggets Introduced

Microsoft Word and

Lotus 1-2-3 first released.

Population (millions) 2346,500 households surveyedIn home interviewsPerson miles traveled (trillions) 1.59

Vehicles/100 people 70Gas /gallon $ 0. 79New house $ 82,600Income per year $ 21,070Dodge RAM 50 Truck $ 5,665

1990 - FOURTH NHTS

Hubble Deployed from Discovery

Exxon Valdez Spill

Honda Accord Top Seller

"The Simpsons “ Aired First Time

Population (millions) 24918,000 + 4,300 add-on HouseholdsComputer Assisted Telephone InterviewPerson miles traveled (trillions) 2.03

Vehicles/100 people 76Gas /gallon $ 1.34New house $ 123,000Income per year $ 28,960Isuzu Rodeo $ 12,4900

1995 - FIFTH NHTS

DVD, Optical Disc Storage Media Announced.

Play Station Released in U.S. 1995 Honda Civic, Most Commonly Stolen Car in 2007

Population (millions) 26221,000 +21,000 add on householdsMail out with CATIPerson miles traveled (trillions) 3.11

Vehicles/100 people 77Gas /gallon $ 1.09New house $ 113,150Income per year $ 35,900New car $ 15,500

2001 - SIXTH NHTS

Academy Award Winning Movie dealt with drugs

not cars

September 11Satellite Radio Begins

Segway Introduced to Revolutionize

Transportation?

Population (millions) 28126,000 + 44,000 add-on householdsTwo-stage CATIPerson miles traveled (trillions) 3.52

Vehicles/100 people 82Gas /gallon $ 1.46New house $ 136,150Income per year $ 42,350New car $ 27,958

2008-09 - SEVENTH NHTS

Automakers Beg for Washington Aid

The top three Internet searches in 2008:

1. Britney Spears2. World Wrestling

Entertainment3. Obama

Richest Nations Agree to Halve Greenhouse Gas

Facebook Passes 100 Million Users

Population (millions) 30525,000 + 125,000 add-on householdsTwo-stage CATIPerson miles traveled (trillions) 3.30

Vehicles/100 people 80Gas /gallon $ 3.39New house $ 238,880Income per year $ 40,523New car $ 28,715

Apple iphone 7G iOS 8

Personal Teleportation App

Press to Transport

President Signs Transportation Reauthorization Bill LATE-TEA

Population (millions) 323Person VMT (trillion ) .23

Vehicles/100 people 8Gas /Gallon $0.79New house $165,000Income per year $38,000New Car NA

2014 - NHTS

Apple iphone 7G iOS 8

Personal Teleportation App

Press to Transport

President Signs Transportation Reauthorization Bill LATE-TEA

Population (millions) 323Person VMT (trillion ) .23

Vehicles/100 people 8Gas /Gallon $0.79New house $165,000Income per year $38,000New Car NA

2014 - NHTS

Apple iphone 7G iOS 8

Personal Teleportation App

Press to Transport

President Signs Transportation Reauthorization Bill LATE-TEA

Population (millions) 323Person VMT (trillion ) .23

Vehicles/100 people 8Gas /Gallon $0.79New house $165,000Income per year $38,000New Car NA

2014 - NHTS

Fundamental Travel TrendsVMT, Registered Vehicles, Gas Cost, Average Income

0%

100%

200%

300%

400%

500%

600%

700%

800%

900%

1000%

1969 1977 1983 1990 1995 2001 2008

Perc

ent G

row

th si

nce

1969

Average Income

Registered Vehicles

Gas Cost

PMT

Travel Trends

050

100150200250300350400450

1977 1983 1990 1995 2001 2008

Annu

al H

ours

per

Per

son

Travel Time per Capita

0000000000

1969 1977 1983 1990 1995 2001 2008

Annu

al V

MT

VMT per Person

-

500,000

1,000,000

1,500,000

2,000,000

2,500,000

1969 1977 1983 1990 1995 2001 2008

VMT in Millions

-

0.50

1.00

1.50

2.00

2.50

1969 1977 1983 1990 1995 2001 2008

PMT/VMT

Demographic Trends

23

38

24

10

5

15

26

24

16

20

0 10 20 30 40

Only Child

Single Sibling

Two Siblings

Three Siblings

Basketball Team

Households with Siblings

1960 2000census

0%10%20%30%40%50%60%70%80%90%

100%

1983 1990 1995 2001 2008

Perc

ent o

f all

Hous

ehol

ds

Household Size

5+ Persons

4 Persons

3 Persons

2 Persons

1 Person

0%5%

10%15%20%25%30%35%40%45%50%

1977 1983 1990 1995 2001 2008

Perc

ent o

f all

Peop

le

Population by Age

Age 5-15

Age 16-25

Age 26-34

Age 35-64

Age 65 and over

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

1983 1990 1995 2001 2008

Perc

ent o

f Pop

ulat

ion

Population - Urban and Rural

Urban

Rural

Demographic Trends

0%

10%

20%

30%

40%

50%

60%

1983 1990 1995 2001 2008

Population by MSA Size

Less than 250,000250,000 to 499,999500,000 to 999,9991 mil to 2 mil

3 mil or more

0%10%20%30%40%50%60%70%80%90%

1977 1983 1990 1995 2001 2008

Population by Race

Other

African American

0%10%20%30%40%50%60%70%80%90%

100%

1983 1995 2001 2008

Housing TypeMulti-Family UnitsSingle Family Units

Note: 1990 NPTS did not

collect dwelling unit information

0

20,000

40,000

60,000

80,000

100,000

120,000

Num

ber o

f Hou

seho

lds (

thou

sand

s)

Three or More Vehicles

Two Vehicles

One Vehicle

No Vehicle

VMT Basics

Travel Time Budget Travel Speed

1.

2.

3. % Δ Population + 1/3 × % Δ Personal Income = % Δ Vehicle Miles of Travel

Income

Pop × Time in SOV Travel × Speed = Vehicle Miles of Travel

Pop × Trip Rate × Trip Length × Vehicle Share = Vehicle Miles of Travel

Trip Rate and Length

1067

1054

1371

1568

1449

1385

9.47 8.68 9.29 9.00

10.78 9.52

0

5

10

15

20

0

200

400

600

800

1000

1200

1400

1600

1800

1977 1983 1990 Adj. 1995 2001 2008

Trip

Len

gth

Annu

al T

rips

per P

erso

n 5+

NPTS and NHTS Work Trip Walking Mode Shares

19695.00%

19774.60% 1983

4.10% 19903.70%

19952.60%

20012.81%

20082.82%

19834.50% 1990

4.00%

19952.30%

20012.92% 2008

3.03%

0%

1%

2%

3%

4%

5%

6%

1969

1970

1971

1972

1973

1974

1975

1976

1977

1978

1979

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

Perc

ent W

alki

ng to

Wor

k

Work Trip "Usual Mode"

Work Trip Actual Mode

Walk is 10.95% of all trips in 2008

Census/ACS Work Trip Percent Walking Mode Share

10.40%

7.40%

5.60%

3.90%

2.90%

2.86%

0%

2%

4%

6%

8%

10%

12%

1960 1970 1980 1990 2000 2010

Perc

ent W

alki

ng to

Wor

k

2009 ACS

Vehicle Occupancies - NHTS

1.401.30 1.30

1.20 1.20 1.201.13

1.90 1.90

1.801.70

1.59 1.64

1.67

0.80

1.00

1.20

1.40

1.60

1.80

2.00

2.20

1969 1974 1979 1984 1989 1994 1999 2004 2009

Occ

upan

cy

Work Trip

All Trips

Carpooling Mode Share (ACS)

20.4% 19.7%

13.4% 12.2%

10.7%

0%

5%

10%

15%

20%

25%

1970 1980 1990 2000 2008

Perc

ent C

arpo

olin

g to

Wor

k

8.90%

6.40%

5.30%

4.70%4.99%4.60%

3.56%3.67%

3.68%

3.40%

2.70% 2.70% 2.20%1.81% 1.56%

1.92%

1.76%

5.11%5.05%

5.13%

0%

1%

2%

3%

4%

5%

6%

7%

8%

9%

10%

Perc

ent o

n Tr

ansi

t

Census/ACS Journey to Work, Usual Mode

NPTS/NHTS Work Trips, Survey Day

NPTS/NHTS All Trips

NHTS 2001 Adjusted

NHTS Work Trip, Work Trip Usual Mode

Transit Mode Share Trends

Time Spent in Travel per Day

49.2 62.8

71.2

84.5

76.4

0

10

20

30

40

50

60

70

80

90

1983 1990 adj. 1995 2001 2008

Min

utes

Person Miles of Travel per Hour (speed, all trips)

28.9 28.330.9

31.0 30.3

28.3

0

5

10

15

20

25

30

35

1977 1983 1990 adj. 1995 2001 2008

MP

H

Mean Household Income Received by Each Quintile1967 to 2008

$0

$20,000

$40,000

$60,000

$80,000

$100,000

$120,000

$140,000

$160,000

$180,000

$200,000

2008

2006

2004

2002

2000

1998

1996

1994

19

92

1990

1988

1986

1984

1982

1980

1978

1976

1974

19

72

1970

1968

Lowest fifth Second fifth

Third fifth Fourth fifth

Highest fifth

Census, 2008 dollars

PMT by Income Quintile

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

1983 1995 2009

Annu

al P

er P

erso

n PM

T

1st 2nd 3rd 4th 5th

Driving Population by Age and Gender

30

0

10

20

30

40

50

60

70

80

90

100

Perc

ent o

f Pop

ulat

ion

Age

Male 2001

Female 2001

Male 2008

Female 2008

PMT and VMT per Capita by Age

0

5000

10000

15000

20000

250002001 Per Capita VMT 2001 Per Capita PMT

2008 Per Capita VMT 2008 Per Capita PMT

PMT and VMT per Capita by Age

0

2000

4000

6000

8000

10000

12000

140002001 Per Capita VMT

2008 Per Capita VMT

Trip Purpose Changes by Gender

0

100

200

300

400

500

600

700

800

900

1990 1995 2001 2009 1990 1995 2001 2009

Women Men

Annu

al P

erso

n Tr

ips

per P

erso

n

To or From Work Family and Personal Errands

School/Church Social and Recreational

Vehicle Availability

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1969 1974 1979 1984 1989 1994 1999 2004 2009

Vehi

cles

per

Vehicles per worker

Vehicles per person 16 and older

Vehicles per person

Vehicles per driver

Declining Zero-Vehicle Households?

0%

5%

10%

15%

20%

25%

1960 1970 1980 1990 2000 2010

Per

cent

NPTS/NHTS Census ACS

Source: CUTR analysis of NHTS ,NPTS,U.S. Census Bureau and 2002-09 ACS

Household Vehicle Ownership DistributionHousehold Percents

National Household Vehicle Ownership Distribution, 2009

HH Vehicles Number of Adults in HH1 2 3 4 5+ All

0 5.79% 2.28% 0.38% 0.19% 0.05% 8.69%

1 20.40% 10.18% 1.31% 0.33% 0.06% 32.28%

2 3.66% 29.04% 2.92% 0.62% 0.08% 36.32%

3 0.74% 9.06% 3.72% 0.78% 0.09% 14.39%

4 0.21% 2.58% 1.54% 0.82% 0.13% 5.30%

5+ 0.14% 1.40% 0.82% 0.49% 0.17% 3.02%

All 30.96% 54.54% 10.69% 3.23% 0.58% 100.00%

20.66% More cars than adults

54.16% Cars equals adults

16.50% Fewer cars than adults

8.69% Zero cars

0

5

10

15

20

25

30

0 Cars, 1 or More Workers

0 cars, 0 Workers

2+ More Workers than

Autos

1 More Worker than

Autos

Cars is Greater Than

Workers

Cars = Workers

1 Car, 1 Worker

Mod

e Sh

are

Perc

ent

2001

2008

Transit Mode Share by Vehicle Availability

Shortage of Vehicles

Transit Market Share by Car Availability

32.5%

15.6%

3.3%13.7%

14.4%

7.2%

13.4%

2008

0 Cars, 1 or More

Workers

0 Cars, 0 Workers

2+ More Workers than Autos

1 More Worker than Autos

Cars is Greater than Workers

Cars = Workers

1 Car, 1 Worker

34.9%

9.7%

8.2%15.4%

11.2%

9.4%

11.2%

2001

0 Cars, 1 or More

Workers

0 Cars, 0 Workers

2+ More Workers than Autos

1 More Worker than Autos

Cars is Greater than Workers

Cars = Workers

1 Car, 1 Worker

Transit Mode Share by Income

0

1

2

3

4

5

6

7

Under $15,000 $15,000-$50,000 $50,000+

Mod

e Sh

are

2008

2001

1995

Transit and ElderlyPerson Trips per Day by Age

Transit Mode Share by Age

Share of Transit Trips by Age Groups

0.0

1.0

2.0

3.0

4.0

5.0

5-14 15-24 25-34 35-44 45-54 55-64 65-74 75-84 85+

Aver

age

Trip

s per

Day

Age Group

0.0%0.5%1.0%1.5%2.0%2.5%3.0%3.5%

5-14 15-24 25-34 35-44 45-54 55-64 65-74 75-84 85+

Tran

sit M

ode

Shar

e

Age Group

5-14, 6.5%

15-24, 21.3%

25-64, 64.0%

65+, 8.2%

41

Changes 2001-2009 Population……………,,…….. +8.7%

Person VMT ………………... -1.6%

VMT/Population………….... -10.4%

Trip Rate………….………..… -4.4%

Trip Length ……….… …..… -6.2%

SOV Share………… .…..… +6.4%

Travel Speed ………….…..… -6.7%

Demographics• Population Diversity• Activity Patterns• Land Use

Economics & Technology• Income & Wealth• Technology • Mode Availability

& Performance

Where are We Going?

Where Have We Been

?

Fundamental Economic and Demographic Changes Continue

Home Ownership Levels at New Lows …

The New York Times,May 2011

Fundamental Economic and Demographic Changes Continue

UPDATE: Gas Prices, Economy Leave Retailers With Mixed May Sales

WSJ, 2011

Americans got used to staycations during the recession, but as the economy begins to recover many are now ready to graduate to the short-stay getaway…

AP, May 2011

Role of Communications Technology• 30% of couples meet online, eHarmony is responsible for 5% of

all marriages

• Holiday shoppers spent 12% more on line in 2010 than 2009

• 85% of Americans own cell phones, 25% of households have gone cell phone only

• 51% of Americans 12 years of age or older have a Facebook account

• There was a 21% increase in online course enrollment in colleges across the country in 2010.

• Households with teenage children had 5.2 online purchases and 4.2 home deliveries per month according to NHTS.

Socio-Demographic Issues Aging population• Saturation of female labor force participation Different young adult behaviors Slowing migration - locked in homes/less mobile Reduced immigration Income/wealth impact• Changing household composition• Slowing of suburbanization?

System Supply Issues Future system supply and speed• Energy and other costs• Environment/climate concerns• Evolving technology impacting

travel• Etc.

How can the current and future NHTS help us address transportation planning and policy issues going forward?

NHTS - A FIX FOR DATA ADDICTS ANDINOCULATION AGAINST UNINFORMED DECISIONS

47