Residential Land Use, Travel Characteristics, and ...onlinepubs.trb.org/onlinepubs/conferences/2011/NHTS1/Hu.pdf · SeongHee Min; Jung H. Seo. Research, Analysis, and Information

1

Residential Land Use, Travel Characteristics, and Demography of Southern California

Presented for TRB WorkshopJune 7, 2011

Hsi-Hwa Hu, Frank Wen, Simon Choi, SeongHee Min; Jung H. Seo

Research, Analysis, and Information Services DepartmentSouthern California Association of Governments

2

Objective of This Study

• Is to use NHTS data to provide updated travel characteristics for SCAG region.

• This presentation includes results of following analysis:1. Overall demographics and travel characteristics2. Relation between residential location and commuting3. Assimilation of Hispanic immigrants’ travel behavior4. Income interaction with land use – transportation

relation

• Results will be provided to SCAG modelers and planners for their analysis.

3

Study Area - SCAG Region

• SCAG – Southern California Association of Governments– A MPO in Southern California

• Six counties:– Los Angeles, Orange, Riverside, San Bernardino,

Ventura, Imperial• 18 million people, 6 million housing, and 8 million jobs • About 6% of the US and half of California• Los Angeles is the largest city

4

SCAG Region

551%

55%

17% 12%

11%4%

SCAG Counties & Population Share

SOUTHERN

3 Coastal counties:Ventura, Los Angeles, Orange76% of Total Population

3 Inland counties:San Bernardino, Riverside, Imperial24 % of Total Population

66

Demographics Characteristics of SCAG Region

• Diversified demographics in Southern California include:

– high share of Hispanic population (45%),

– lot’s of immigrants (30% are foreign born),

– aging of baby boomer (16% in 2035)

7

NHTS

• Thank FHWA and Transportation System Information (TSI) of California Department of Transportation (Caltrans) for supporting 2009 NHTS California add-on data.

• With about 6,700 household and 15,000 person samples, 2009 NHTS provides valuable data and sufficient observations to analyze travel characteristics of SCAG region.

• This study analyzes travel characteristics at person level

8

• Overall demographics and travel characteristics• Relation between residential location and commuting• Assimilation of Hispnanic immigrants’ travel behavior• Income interaction with land use – transportation relation

99

Weekday Person Travel

• Compared to the US, SCAG residents drive less and travel shorter distance, but use more non-motorized modes (walk, bicycle) and transit

0

5

10

15

20

25

30

35

Daily Distance Daily VMT

Daily Travel Distance

SCAG US

0%

10%

20%

30%

40%

50%

60%

70%

Driver Passenger Non-motorized Transit

Mode Share

SCAG US

* Demographics & Travel

1010

Travel by Age

• Daily trips and travel distance are the highest for the working age population (25-64).

• The elderly still rely on a car, but drive less.


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

100%

< 16 16-24 25-49 50-64 65-74 > 74

Driver Passenger

Auto Use by Age

Daily Trips and Distance by Age

1111

Travel by Age (Elderly)

• 20% - 33% of the elderly did not travel on the survey day.

• However, when they travel, their trips are no less than the younger.

Non-work Trips by Age

% of Persons Did Not Travel

0%

5%

10%

15%

20%

25%

30%

35%

40%

Below16 16-24 25-49 50-64 65-74 75+

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

Below16 16-24 25-49 50-64 65-74 75+


1212

Travel by Race/Ethnicity

• Compared to other groups, Hispanic population drive less; use more non-motorized and transit modes.

Daily Travel by Race/Ethnicity

Race Trips Distance Driver_Auto Passngr_Auto NM Transit

NH_WH 4.0 29 67% 18% 12% 1%

NH_BK 3.8 22 56% 20% 17% 5%

NH_AS 3.6 26 59% 23% 13% 2%

HISP 3.7 24 46% 24% 21% 6%


1313

Time of Day(% persons are traveling)

0%

5%

10%

15%

20%

25%

30%

35%

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Time of Day - SCAG vs. US (by hour)

SCAG US

• Compared to the US, SCAG region shows higher % of people traveling in the morning (4:00-8:00).

Note: This chart shows % of persons who traveled within each hourly period. The purpose is to show the difference between US and SCAG, not for estimating travel length

0.0%2.0%4.0%6.0%8.0%

10.0%12.0%14.0%16.0%18.0%

1 62 123

184

245

306

367

428

489

550

611

672

733

794

855

916

977

1038

1099

1160

1221

1282

1343

1404

Time of Day - SCAG vs. US (by minute)

SCAG US


1414

Time of Day by Purpose

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Time of Day by HBW

HBW

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Time of Day by NHB

NHB

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Time of Day by HBO

HBO

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Time of Day by HB Shopping

HBSHOP

school

lunch

open hoursschool


1515


0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Time of Day HB Social/Recreation

HBSOC

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23


HBW HBO NHB HBSHOP HBSOC

After work

• PM peak appears during 2 pm-6 pm due to travel demand for multiple activities

• PM peak lasts longer than AM peak.


1616

Time of Day ofElderly & Hispanic

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Time of Day - Old vs. Young

16-64 65+

• Peak travel period for the elderly is around noon.• More significant two peaks to Hispanic (7 am-8 am

and 3 pm-4 pm) than non-Hispanic

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Time of Day - Hispanic vs. Non-Hispanic

Non-Hisp HISP


17

• Overall demographics and travel characteristics• Relation between residential location and commuting• Assimilation of Hispanic immigrants’ travel behavior• Income interaction with land use – transportation relation

18

Introduction

• Travel behavior theory recognized that daily travel choices are related to choices about residential location, school location, job location, and auto ownership.

• Is this relation described above the same for people with different demographic background?

• We use NHTS to examine the relation between residential density of neighborhoods, distance to work, and mode for commute

– Neighborhoods: Using 11K SCAG TAZs (Census block group)

* Residential Location and Commuting

19

Findings

• Results are as expected.• Residents living in higher density neighborhoods:

– Cars are less available to household members. – Transit services are more available.– Shorter distance to work (work location closer to

home)– Workers are less likely to commute by a car; more

likely by transit and non-motorized modes. • Commuting time is about the same for workers living in

neighborhoods with different density.


20

Residential Density – # housing/acre

LAX

Downtown LA

2121

Residential Density & Commuting Distance• Living in higher density neighborhoods:

• Shorter commuting distance. • Commuting time is about the same for all density.


0

5

10

15

20

25

30

35

0

2

4

6

8

10

12

14

16

18

20

<2 2-6 6-18 18-38 38-100 100+

Commuting Distance and Time

DISTtoWK

TIMEtoWK

Density from low to high

2222

Residential Density & Commuting Mode• Living in higher density neighborhoods:

– Cars are less available. – Transit services are more available.– Workers are less likely to commute by a car; more

likely by transit and non-motorized modes.

Residential Transit % Commuting ModeDensity Car/Hhsize Density Auto Transit NM<2 0.9 0.0 93 2 12-6 0.8 0.0 91 2 26-18 0.6 0.1 88 4 318-38 0.5 0.3 82 10 538-100 0.5 0.5 78 12 6100+ 0.3 1.2 63 19 14


Commuting Mode by Density

2323

How about the Hispanic Population?

• Similar to total population, the Hispanic living in higher density neighborhoods are: • less likely to live in a single-family house, • lower car ownership, and• shorter commuting distance

Households Res Density % SDO Car/Hhsize % No car DISTtoWK TIMEtoWK<2 75 0.7 5 12 222-6 79 0.6 2 19 316-18 57 0.5 13 13 2718-38 23 0.4 18 12 3138-100 11 0.3 29 10 33100+ 0 0.2 49 7 27


Household Characteristics and Commuting

2424

Hispanic - Commuting Mode

0

2

4

6

8

10

12

14

16

<2 2-6 6-18 18-38 38-100 100+

% Carpool/passenger Commuting

Hisp Al l

• Compared to total population,– Hispanic commuters have higher % of transit use, especially

in higher density areas.– They also have higher % of carpool, especially in lower

density areas.

0

5

10

15

20

25

30

<2 2-6 6-18 18-38 38-100 100+

% Transit Commuting

Hisp Al l


25

Long Distance Commute

0

10

20

30

40

50

60

I-C I-I C-C C-I

Commuting Time

• According to 2009 ACS, about 300,000 workers living in inland counties commute long time to coastal counties.

• Their median commuting time is 50 minutes. 97% by cars.• 2009 NHTS shows consistent pattern as ACS.• Why do they want to commute for long time/distance?


0

10

20

30

40

0

10

20

30

40

50

60

I-C I-I C-C C-I

Commuting Time and Distance

Min Dist

2009 ACS 2009 NHTS

26

Long Distance Commute (2)

-

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

100,000

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

I-C I-I C-C C-I

Low

Med

High

V. High

M Hhinc

• Inland neighborhoods are characterized as lower-density, with more affordable single-family housings than coastal counterparts.

• Median household income of inter-county commuters are higher than other commuters


• Some people who prefer to live in low-density living environment would like to trade off commuting time.

• Their income can support their choice on long-distance driving.

Income Distribution of Commuters

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

I-C I-I C-C C-I

>100

38-100

18-38

6-18

2-6

<2

Residential Density Distribution

ACS

27

• Overall demographics and travel characteristics• Relation between residential location and commuting• Assimilation of Hispanic immigrants’ travel behavior• Income interaction with land use – transportation relation

2828

Introduction

• Each year, many immigrants move to Southern California.• Will immigrants change their behavior after years living in

this region? How about their residential location-housing-travel relation.

• The objective is to analyze the difference between newer immigrants, long-term immigrants, and the US born.

• Focus on adults between 30-60 years old – they are primary decision makers of their family.

• By three race/ethnicity groups: Hispanic, Non-Hispanic White, and others. This study focuses on Hispanic population, due to larger share to total population.

* immigrants’ travel behavior

2929

Findings

• As Hispanic immigrants stay longer in the US, their income status is improved, and they tend to live in a single-family house in a lower-density neighborhood, just similar to the US born.

• They also commute longer distance, drive more and use less transit than new Hispanic immigrants.

• Our earlier finding regarding Hispanic’s driving less and using more transit is probably due to large proportion of newer immigrants.

• This travel behavior assimilation of Hispanic immigrants and the second generation challenges transportation modeling that use race/ethnicity.


3030

Immigrants Aged 30-60 Years Old(2009 ACS)

• 45% of total population, and 2/3 of Hispanic, are immigrants.

• Half of Hispanic are immigrants who entered US < 30 years.

Persons aged 30-60, by immigration status

-

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

Hispanic NH White NH Black NH Asian NH Other

<15 yrs 15-29 30+ US Born


3131

Household Income

• Income status is improved to Hispanic immigrants as they stay longer in the US.

0

20

40

60

80

100

< =15 16-30 > 30 US born

NH- White

< 60K > 60K

010203040506070

< =15 16-30 > 30 US born

Others

< 60K > 60K

0

20

40

60

80

100

< =15 16-30 > 30 US born

Hispanic

< 60K > 60K

Household Income by Immigration Status


3232

Household Size & Housing Type

• As Hispanic immigrants staying longer in the US:

1. smaller household size.

2. more likely to live in a single-family house

• Similar to the US born.

0.00.51.01.52.02.53.03.54.04.55.0

NH-W HISP Others

Household Size

< =15 16-30 > 30 US born

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

NH-W HISP Others

% Living in Single Detached Houseing

< =15 16-30 > 30 US born


3333

Commuting Distance and Mode

• As Hispanic immigrants staying longer in the US:

1. longer commuting distance.

2. more likely to use a car as commuting mode.

Distance to Work

Years in US NH-W HISP Others< =15 14 12 1316-30 16 14 13> 30 18 16 15US born 17 16 14


0.010.020.030.040.050.060.070.080.090.0

100.0

NH-W HISP Others

% Commuting by Auto

< =15 16-30 > 30 US born

3434

Other Commuting Modes

• As Hispanic immigrants staying longer in the US:– The use of transit and NM modes significantly drop

• The impression of high transit use of Hispanic population may be attributed to large proportion of newer immigrants.

0

5

10

15

20

< =15 16-30 > 30 US born

NH White

Transit NM

0

5

10

15

20

< =15 16-30 > 30 US born

Others

Transit NM

0

5

10

15

20

< =15 16-30 > 30 US born

Hsipanic

Transit NM

Share of Transit and Non-motorized


35

• Overall demographics and travel characteristics• Relation between residential location and commuting• Assimilation of immigrants’ travel behavior• Income interaction with land use – transportation relation

36

Introduction

• It is known that people with higher income generally drive more. What will happen if higher income people living in high density neighborhoods?

• Does influence of land use density outweigh income on vehicle use?

• This study is to analyze travel behavior of by two neighborhood characteristics: density and median household income.– 5 land use density categories: <6, 6-10, 10-18, 18-38, 38+– 2 levels of median household income: < $40K (low income), >

$40K (medium to high income)

* Income Interaction

37

Findings

• For lower income residents, as their neighborhood density increases, their work location is closer to home. They tend to drive less, walk more, and use more transit.

• Higher income (or non low income) residents show different pattern. Generally speaking, residential density has less significant association with their travel behavior. They do not drive less or use more transit as they live in higher density neighborhoods.

• This study does not analyze residential self selection.

• Land use policies that promote higher density development to reduce car use as well as greenhouse emission should be further reviewed by different demographic characteristics.


38

Household Income

LAX

Downtown LA

39

Car Availability

• Density has no significant association with car availability for high income neighborhoods.

0%

20%

40%

60%

80%

100%

Low Inc High Inc

Car/hhsize


40

Commuting Distance

• Overall, commuting distance decreases with density. People live closer to work location while living in high density areas.

0

5

10

15

20

Low Inc High Inc

Commuting Distance


41

Commuting Mode• For residents living in low income neighborhoods, % of auto use

for commute decreases.• For residents living in high income neighborhoods, residential

density has no significant association with auto use.


50

60

70

80

90

100

Low Inc High Inc

% Auto

42

Non-Work Travel

• Residential density has no significant association with car use for non-work purpose for residents of high income neighborhoods.

0%

10%

20%

30%

40%

50%

60%

70%

Low Inc M-H Inc

% NW Drive Alone


43

Non-Motorized & Transit• Are people living in higher density neighborhoods more likely

to travel more by non-motorized modes or transit? NHTS provides data regarding the number of walk/bike trips last week, and transit trips last month.

• Density has no clear effect on walking/biking/transit use for people living in high income neighborhoods.

0.0

2.0

4.0

6.0

8.0

10.0

Low Inc M-H Inc

# Walking Last Week

0.0

0.5

1.0

1.5

2.0

Low Inc M-H Inc

# Biking Last Week

0%

2%

4%

6%

8%

10%

12%

Low Inc M-H Inc

# Transit Last Month


44

Personal Vehicle Miles of Travel• For low income neighborhoods, personal VMT

decreases with higher density.• For high income neighborhoods, personal VMT is

about the same for residential density > 6 units/acre.

0

5

10

15

20

25

30

35

Low Inc High Inc

Personal VMT


45

Test Mean Difference

Test of Mean Difference by Residential Densiy > 2 units/acre (Pr>F)

Low (< 30K) Medium (30-80K) High (80K+)

Commuting

Distance to Work 0.11 0.000 0.34

Time to Work 0.20 0.05 0.74

Commute by Auto 0.000 0.000 0.25

Daily Travel

Daily Trips 0.14 0.36 0.20

Daily Distance 0.004 0.17 0.003

Daily Drive Alone Trips 0.000 0.95 0.21

VMT 0.000 0.49 0.03red font: means are significantly different (persons . 16 yr. old)

• The table shows that the auto use for commute, daily drive alone trips, and person VMT are about the same with residential density > 2 units/acre among medium or high income people.


46

Conclusion

• NHTS provides valuable information for us to understand regional travel pattern and its relation with land use and demographics characteristics.

• Future studies:– Analyze travel-land use-demographics with household data– Understand future pattern of immigration status– More test on income interaction with land use on vehicle use


47

Thank you

Documents

Residential Land Use, Travel Characteristics, and ...onlinepubs.trb.org/onlinepubs/conferences/2011/NHTS1/Hu.pdf · SeongHee Min; Jung H. Seo. Research, Analysis, and Information