Travel Time Use over Five Decades 

Chen Song 

University of International Business and Economics 

Chao Wei 

George Washington University 

November 17, 2015 
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Outline

Overview

Related Literature

Demographics Shifts

Aggregate Forces

Summary
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Time Use Surveys

Five major time-use surveys

1965-1966, 1975-1976, 1985, 1992-1994, 2003-2013 (annual)

Variables of interest

–Major time use categories: market work, non-market work

and leisure

–Within each category: travel time and corresponding

non-travel time

Our sample

–1975-2013: older than 18

–1965-2013: older than 19, younger than 65, not retired

–Excluding those with missing values for key demographics.
Total Analysis Analysis Number of 

Dataset Survey Sample Sample 1 Sample 2 T ime Use & 

Size Size Size Travel Categories 

1965 Americans' Use 2,001 1,934 [95], [9) 

of Time 

1975 Time Use in 2,406 2,217 1,870 [87], [9) 

Economic and Social 

Accounts 

1985 Americans' Use 4,939 4,240 3,629 [88], [9) 

of Time 

1993 National Human 9,383 7,258 6,018 [91], [10) 

Activity Pattern 

Survey 

2003 American Time 20,720 19,759 16,255 1435], 158) 

2004 Use Survey 13,973 13,318 10,889 1449], [68) 

2005 13,038 12,418 10,255 1456], [76) 

2006 12,943 12,200 9,970 1456], [76] 

2007 12,248 11 ,606 9,477 1459], [76] 

2008 12,723 12,108 9,876 1459], [76] 

2009 13,133 12,568 10,220 1459], [76) 

2010 13,260 12,679 10,277 1459], [76] 

2011 12,479 11,978 9,623 1459], [76] 

2012 12,443 11,975 9,557 1459], [76) 

2013 11,385 10,952 8,626 1459], [76) 

B .. ~ ') "(" 

Overview Related Literature Demographics Shifts Aggregate Forces Summary
i.q 

LO 

0 

LO 

oi 

,;,e. 

Q) LO Q) 

3: cri 

8.29 

LO 

cO 

Change: LO 

Lei 1993-1975 +1.67*** 

LO 2003-1993 -1.07*** 

-<i 2013-2003 -0.74*** 

~ *** p<O.D1 

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 

Overview Related Literature Demographics Shifts Aggregate Forces Summary

Total Variations in Travel Time
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Intriguing Issues 

To what extent do demographic shifts contribute to the

evolving patterns of travel time use?

To what extent can aggregate driving forces common

to all demographic groups account for variations in

total travel time?

How travel time co-vary with other time use categories

over time across demographic cells?

What can we say about fluctuations in total travel 

time, especially the decline after 2003? 
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Explaining Travel Time Variations

Evaluating the Roles of Demographic shifts

Age demographics (baby boomers)

Work-gender groups

Education

Whether there are children in the household

Changes in time allocation

Economizing on travel 

Shift in time allocation 
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Main Findings 

Total travel time features an inverted-U shape,

registering a 20 percent increase from 1975 to 1993, but

an 18 percent decline from 1993 to 2013.

Demographic shifts explain about 45% of the increase

during 1975-1993. Increases in education attainment

alone contribute 28%.

Demographic shifts explain 16% of the decline in travel

time during 1993-2003, but play little role since 2003.

Shift of time allocation from travel-intensive nonmarket work to travel-non-intensive leisure is a major

factor (around 50%) behind the decline since 2003.
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Related Literature

Time Use Study

Aguiar and Hurst (2007) 

Ramey and Francis (2009) 

National Personal/Household Travel Survey

Strong focus on travel

Not linked with broad time use measures

Not linked with data sets such as CPS 

Not annual. 
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Question I 

Can evolving demographics explain

changes in travel time?
;::: 

LO 

o; 

1975 

1975 

A. Age Groups 

1 --18-19 - - 20-49 -- -- 50-64 - - 65+ I 

1985 1995 2005 2015 

C. Education Groups 

1985 

Grade<12 

12<Grade<16 

1995 

-·---. .'- ' :::: 

Grade=12 

Grade=16+ 

2005 2015 

B. Work-Gender Groups 

~~~-------------~ 

Female Nonworking Female Working 

LO Male Nonworking Male Working 

M L':;:======:::;:::::=======;======:::;::::======~ 

1975 1985 1995 2005 2015 

D. Have Children vs. No Children 

;::: 

1-- Have Children - - No Children I 

1975 1985 1995 2005 2015 

Overview Related Literature Demographics Shifts Aggregate Forces Summary

Travel Time Patterns by Demographics
1975 1985 1993 2003 2013 Average Differenoo Difference Difference 

1975-2013 1993-1975 2003-1993 2013-2003 

Panel A: By Age Croups 

lS-19 2.7 3.4 3.0 3.4 3.2 3.1 0.2 0.4 -0.2 

20-49 58.6 62.4 67.1 58.5 52.5 57.2 8.5 -8.5 -6.0 

50-64 20.8 20.4 18.2 22.0 26.0 23.4 -2.5 3.8 4.0 

65+ 17.9 13.7 11.7 16.1 18.4 16.3 -0.2 4.4 2.2 

Panel B: By Work-Gender Croups 

Female Nonworker 31.0 25.0 21.1 21.3 22.3 22.1 -9.9 0.2 1.0 

Female Worker 21.7 30.6 33.2 30.7 29.4 30.2 11.5 -2.6 -1.3 

Male Nonworker 12.5 12.1 10.1 12.2 14.8 13.00 -2.4 2.1 2.6 

Male Worker 34.8 32.2 35.5 35.8 33.5 34.7 0.8 0.3 -2.4 

Panel C: By Education Levels 

Crade<12 38.9 17.5 10.3 15.4 11.8 15.3 -28.7 5.1 -3.6 

Crade= l2 35.6 43.2 36.l 32.5 30.3 33.l 0.5 -3.6 -2.2 

Crade:l 3-15 12.9 17.4 25.0 26.5 26.1 24.8 12. 1 1.5 -0.4 

Crade= l6+ 12.6 21.9 28.7 25.6 31.8 26.8 16.1 -3.0 6.2 

Panel D: By Have Child or Not 

No Child 52.8 63.2 66.0 60.6 64.2 61.9 13.2 -5.4 3.5 

Have Child (ren} 47.2 36.8 34.0 39.4 35.8 38.1 -13.2 5.4 -3.5 

::: " .. 

Overview Related Literature Demographics Shifts Aggregate Forces Summary

Evolving Weights (in Percentage) of Demographic Groups
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Quantifying the Role of 

Demographic Shifts 

Method: Blinder-Oaxaca Decomposition

Regression equation: Yt = Xt

�

βt + εt

Nine dummy variables:

Three age dummies: 20-49, 50-64, above 65;

One gender dummy

One dummy for work status

Three education dummies: high school, some college,

college and above

One dummy for having children in the household
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Blinder-Oaxaca Decomposition

)� � � Y (� − � t1 − Y t0 = (Xt1 − Xt0 βt0 + Xt1 βt1 βt0 )

Unconditional mean change is decomposed into

–“Explained”, the portion due to evolving demographic

weights, given a fixed set of coefficient estimates and

–“Unexplained”, the portion due to changes in the

relevance of demographics to travel time use and

changes in fixed time effects, given fixed demographic

weights.

Reference: starting or ending year, two-year pooled
Panel A: Results of Two-year Pooled M ethod 

1975-1993 1993-2003 2003-2013 

Difference 1.67*** -1.07*** -0.74*** 

Explained 0.75*** -0.18*** -0.02 

-Age 0.18*** -0.10*** -0.05*** 

-Work-Gender 0.12*** -0.02 -0.06*** 

-Education 0.47*** -0.06*** 0.11 *** 

-Child -0.01 0.01 -0.01 * 

Unexplained 0.91 ** -0.89*** -0.73*** 

Panel B: Ratio Relative to Difference 

1975-1993 1993-2003 2003-2013 

Explained 45.2% 16% 2.2% 

-Age 10.5% 8.9% 7.6% 

-Work-Gender 7.1% 1.8% 8.2% 

-Education 27.9% 6.3% -15.0% 

-Child -0.3% -1.0% 1.6% 

Unexplained 54.8% 84% 97.8% 

• D • Di' • • • ; = • ~ "')OJ'-

Overview Related Literature Demographics Shifts Aggregate Forces Summary

* p < 0.1, ** p < 0.05, *** p < 0.01
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Question II 

What are aggregate forces behind 

common variations in travel time? 
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Search for Aggregate Forces

Economizing on Travel

–Defined as changes in the ratios of travel to non-travel

time related to the same category of activity;

–Most likely caused by technology or gasoline price 

fluctuations. 

Shifts in Time Allocation

–Shifts of time among activities with different travel 

intensity; 

–Various substitution patterns between travel time and 

other time uses. 
Corresponding NonTravel Time 

Travel Time Use 

Classification 

Market Work: work for pay Work Travel 

and related activities 

Non-Market Work Non-Market Work Travel 

Leisure Leisure Travel 

Other Time Uses Other Travel 

Examples of Travel 

Activities 

Travel related to work, such 

as commuting to/from 

work, and non-commuting 

work-related travel 

Home Production Travel, 

Obtaining Travel, Child 

Care Travel and Other Care 

Travel 

Travel related to sports, 

exercises, recreation, 

socializing, entertainment, 

eating and drinking, 

volunteering and other 

leisure activities 

Travel related to education 

and other activities 

Overview Related Literature Demographics Shifts Aggregate Forces Summary
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Two Historical Periods

First focus on 2003-2013

–Annual data 

–Consistent measures 

–Age range: ≥ 18 

The longer sample of 1975-2013

–1975, 1985, 1993, 2003-2013

–Nearly consistent measures but not perfect

–Age range: ≥ 18
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Travel-Intensive and Non-Intensive

Activity (2003) 
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Economizing on Travel or

Shift in Time Allocation 
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Substitution Patterns of Travel and

Other Time Uses 

Forming 120 cells based on demographics

Computing year-to-year or ten-year differences in time

use categories for all cells

Running the regression

j + βj

�Htravel j �H = αj + ε it it it

Interpretation: not causal, however, 

–Negative Coefficients: substitutable 

–Positive Coefficients: complementary 
Table 6: Substitution Patterns across Time Use Categories (2003-2013) 

Time Use Category Sample Baseline Demographics Time Dummies Demo + Time 

( on-Travel Time) Average fJ S.E. fJ S.E. fJ S.E. fJ S.E. 

(1) (2) (3) (4) (5) (6) (7) (8) (9) 

Work 24.39 -9.75 (7.24) -9.80 (7.27) -10.01 (7.20) -10.05 (7.22) 

Non-marke t Work 18.36 -11.84' (7.10) -11.83' (7.13) -12.02' (7.05) -12.01' (7.08) 

- Child Care 3.64 -5.19"' (1.85) -5.22'" (1.85) -4.96'" (1.87) _4,99••• (1.88) 

- Other Care 0.83 3.09 (2.56) 3.10 (2.57) 3.13 (2.50) 3.14 (2.51) 

- Obtaining Goods/Services 3.14 12.45'" (2.61) 12.46 ... (2.63) 12.47'" (2.64) 12.49'" (2.65) 

- Home Production 10.75 -22.19 ... (5.05) -22.18"' (5.08) -22.66"' (5.05) -22.65"' (5.07) 

H ome Leisure 86.41 -113.53"' (15.44) -113.50'" (15.49) -113.98'" (15.52) -113.95"' (15.58) 

- Computer + TV 20.35 -53.37"' (9.54) -53.33'" (9.58) -53.t4·- (9.58) -53.18"' (9.63) 

- Sleeping 60.33 -53.37"' (10.17) -53.34'" (10.22) -53.90'" (10.16) -53.88'" (10.21) 

- Other Home Leisure 5.73 -6.87 (4.19) -6.82 (4.21) -6.93 (4.19) -6.89 (4.21) 

Outside Le isure 9.71 17.76' (9.23) 17.80' (9.26) 17.75' (9.29) 17.79' (9.33) 

- Exercise and Sports 2.06 10.33'" (3.52) 10.34'" (3.53) 10.24'" (3.53) 10.24'" (3.54) 

- Socializing 7.06 5.94 (8.40) 5.98 (8.43) 6.01 (8.38) 6.05 (8.41) 

- Entertainment and Arts 0.60 1.49 (1.38) 1.48 (1.39) 1.51 (1.38) 1.50 (1.39) 

Ot her Leisure 17.57 11.1-,.•• (5.95) 11.15-• (5.98) 18.42'" (5.90) 18.40'" (5.93) 

- Garden and Pet 2.05 -2.92 (2.55) -2.92 (2.56) -2.86 (2.50) -2.87 (2.51) 

- Eating 7.85 5.53" (2.54) 5.54" (2.47) 5.52*' (2.45) 5.53'* (2.46) 

- Personal Care 4.73 5.19- (2.19) 5.20" (2.20) 5.37" (2.19) 5.38'* (2.20) 

- Self Care 0.61 0.49 (2.53) 0.51 (2.54) 0.75 (2.56) 0.76 (2.57) 

- Own Medicare 0.36 3.84" (1.54) 3.84" (1.55) 3.85" (1.56) 3.84" (1.56) 

- Civic 1.97 5.63" (2.50) 5.59" (2.51) 5.79" (2.48) 5.75" (2.49) 

Ot her 3.02 -0.41 (8.01) -0.43 (8.04) -0.16 (8.03) -0.19 (8.06) 

- Education 1.63 -1.17 (7.19) -1.22 (7.22) -1.23 (7.23) -1.28 (7.27} 

- Other {excluding education) 1.39 0.77 (3.96) 0.79 (3.98) 1.07 (3.92) 1.09 (3.93) 

•p < 0.10, •• p < 0.05, ... p < 0.01 

Note: All coefficients are multiplied by I 00. 

~ D ~ ~ DP ~ ~ - ~ ~ .,. ~ :§: -0'<.C" 

Overview Related Literature Demographics Shifts Aggregate Forces Summary
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Substitution Patterns across Time Use

Categories (2003-2013) 

For every 100-hour reduction in total travel,

Complementary time uses (selected): 

–12-hour reduction in time on obtaining goods and 

services (non-travel portion) 

–10-hour reduction in exercise and sports 

Substitutionary time uses (selected) 

–53-hour in time on entertainment using computer&TV 

–53-hour on sleeping 

–22-hour on home production (housework) 
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Substitution Patterns across Time Use

Categories (2003-2013) 

For every 100-hour reduction in total travel,

Complementary time uses (selected): 

–12-hour reduction in time on obtaining goods and 

services (non-travel portion) 

–10-hour reduction in exercise and sports 

Substitutionary time uses (selected) 

–56-hour in time on entertainment using computer&TV 

–56-hour on sleeping 

–24-hour on home production (housework) 
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Travel Time Allocation over a Long

Horizon: 1975-2013 

For measure consistency, 

–Work travel (market work) 

–Obtaining travel (obtaining; nonmarket work) 

–Leisure travel (socializing, recreation and passive

leisure; core leisure)

62-74% of total travel, around 40% of time use
A. Work (all} 

0 

(") 

0 

~ 

"' 

0 

(") 

0 

"' 

1975 1985 1995 2005 2015 

C. Obtaining 

~ I - Time Use (non-travel) - - - - Travel Time I 

1975 1985 1995 2005 2015 

0 

(") 

0 

"' 

B. Work (workers) 

"' 

0 

1975 

~ 

1975 

',,,"\ .. ,, ... "' 

1985 1995 2005 2015 

D. Leisure (narrow) 

1985 1995 2005 2015 

Overview Related Literature Demographics Shifts Aggregate Forces Summary

Time Use and Travel Time: 1975-2013
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Substitution Patterns across Time Use

Categories (1975-2013) 

For every 100-hour reduction in total travel,

Complementary time uses (selected):

–21-hour reduction in time on civil activities

–11-hour reduction in socializing

–9-hour reduction in exercise and sports

–9-hour reduction in obtaining goods and services

Substitutionary time uses (selected):

–56-hour on sleeping

–40-hour in time on entertainment using TV

–25-hour on leisure at home not including TV
Demographic shift 

Shift of time 

allocation 

Economizing on 

travel 

Substitution 

Patterns 

1975-1993 1993-2003 2003-2013 

45% 16% 2% 

Baby boomers Baby boomers Shift of old workers 

coming of age aging to retirement 

Shift of women into Decline in relative Shift of younger 

work status working population. pop. to non-work 

Increase in Slowdown in Stable education 

education level education growth growth 

Both work and Work and leisure Shift from nonleisure travel (narrow) travel market work to 

increase with decline with leisure 

corresponding time corresponding time 

use use. 

Opposite to Possible No strong evidence 

economizing economizing 

Complementary: obtaining goods & services, and etc . 

Substitutionary: Entertainment using computer & TV, Sleeping 

Overview Related Literature Demographics Shifts Aggregate Forces Summary

Summary on Time Allocation
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Model Ingredients

Different growth rates of productivity in market,

non-market and leisure sector

Gasoline price change

Change of technology in travel sector

In addition to

Aging of baby boomers

Changes in labor force participation

Changes in education level
Overview Related Literature Demographics Shifts Aggregate Forces Summary

A Close Look at

Non-Market Work Travel 
0 

C\J 

0 

(") 

0 

"' 

~ 

0 

A. Child Care 

~~~~~~~~~~~~~ 

2004 2007 2010 2013 

C. Home Production 

0 '·.1 

0 

C\J 

0 

(") 

0 

"' ~~~~~~~~~~~~-

2004 2007 2010 2013 

0 

C\J 

0 

(") 

0 

"' 

0 

C\J 

0 

(") 

B. Other Care 

~~~~~~~~~~~~~ 

2004 2007 2010 2013 

D. Obtaining 

~ I - Time Use (non-travel) - - - - Travel Time I 

2004 2007 2010 2013 

Overview Related Literature Demographics Shifts Aggregate Forces Summary

Evolution of Non-Market Work Travel
Overview Related Literature Demographics Shifts Aggregate Forces Summary

Decomposition of 

Disaggregated Travel Time