Residential Land Use, Travel Characteristics, and...
Transcript of Residential Land Use, Travel Characteristics, and...
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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
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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.
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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
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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
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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)
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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
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• Overall demographics and travel characteristics• Relation between residential location and commuting• Assimilation of Hispnanic immigrants’ travel behavior• Income interaction with land use – transportation relation
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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
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Daily Distance Daily VMT
Daily Travel Distance
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Driver Passenger Non-motorized Transit
Mode Share
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* Demographics & Travel
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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.
* Demographics & Travel
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
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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
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* Demographics & Travel
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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%
* Demographics & Travel
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Time of Day(% persons are traveling)
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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%
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Time of Day - SCAG vs. US (by minute)
SCAG US
* Demographics & Travel
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Time of Day by Purpose
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Time of Day by HB Shopping
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school
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open hoursschool
* Demographics & Travel
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Time of Day by Purpose
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Time of Day by Purpose
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.
* Demographics & Travel
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Time of Day ofElderly & Hispanic
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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
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Time of Day - Hispanic vs. Non-Hispanic
Non-Hisp HISP
* Demographics & Travel
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• Overall demographics and travel characteristics• Relation between residential location and commuting• Assimilation of Hispanic immigrants’ travel behavior• Income interaction with land use – transportation relation
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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
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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.
* Residential Location and Commuting
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Residential Density – # housing/acre
LAX
Downtown LA
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Residential Density & Commuting Distance• Living in higher density neighborhoods:
• Shorter commuting distance. • Commuting time is about the same for all density.
* Residential Location and Commuting
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Commuting Distance and Time
DISTtoWK
TIMEtoWK
Density from low to high
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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
* Residential Location and Commuting
Commuting Mode by Density
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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
* Residential Location and Commuting
Household Characteristics and Commuting
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Hispanic - Commuting Mode
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% Carpool/passenger Commuting
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• 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.
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% Transit Commuting
Hisp Al l
* Residential Location and Commuting
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Long Distance Commute
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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?
* Residential Location and Commuting
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Commuting Time and Distance
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Long Distance Commute (2)
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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
* Residential Location and Commuting
• 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
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Residential Density Distribution
ACS
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• Overall demographics and travel characteristics• Relation between residential location and commuting• Assimilation of Hispanic immigrants’ travel behavior• Income interaction with land use – transportation relation
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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
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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.
* immigrants’ travel behavior
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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
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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
* immigrants’ travel behavior
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Household Income
• Income status is improved to Hispanic immigrants as they stay longer in the US.
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< 60K > 60K
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Household Income by Immigration Status
* immigrants’ travel behavior
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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
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* immigrants’ travel behavior
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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
* immigrants’ travel behavior
0.010.020.030.040.050.060.070.080.090.0
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NH-W HISP Others
% Commuting by Auto
< =15 16-30 > 30 US born
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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.
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Share of Transit and Non-motorized
* immigrants’ travel behavior
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• Overall demographics and travel characteristics• Relation between residential location and commuting• Assimilation of immigrants’ travel behavior• Income interaction with land use – transportation relation
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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
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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.
* Income Interaction
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Household Income
LAX
Downtown LA
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Car Availability
• Density has no significant association with car availability for high income neighborhoods.
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Low Inc High Inc
Car/hhsize
* Income Interaction
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Commuting Distance
• Overall, commuting distance decreases with density. People live closer to work location while living in high density areas.
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Commuting Distance
* Income Interaction
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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.
* Income Interaction
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Low Inc High Inc
% Auto
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Non-Work Travel
• Residential density has no significant association with car use for non-work purpose for residents of high income neighborhoods.
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70%
Low Inc M-H Inc
% NW Drive Alone
* Income Interaction
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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
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Low Inc M-H Inc
# Walking Last Week
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# Biking Last Week
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Low Inc M-H Inc
# Transit Last Month
* Income Interaction
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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.
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Personal VMT
* Income Interaction
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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.
* Income Interaction
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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
* Income Interaction
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Thank you