This report provides a summary of analyses using data from long-distance tours by each household from an 8-week California Household Travel Survey travel log. The first analysis uses Structural Equations Models (SEM) and a simpler variant called Path Analysis on three censored variables (tour miles by air, miles driving, and miles by public transportation) and two categorical variables (main trip tour purpose) and number of overnight stays. The second analysis uses Latent Class Cluster Analysis (LCCA) to identify five distinct, informative patterns of long-distance travel. This analysis shows that long-distance tours for vacation, business travel, medical, and shopping are substantially distinct in terms of their travel characteristics and correspond to different combinations of other activities in the tour and they are done by different types of households. The methods used here to identify the typology of long-distance travel can be easily expanded to include a variety of other explanatory variables of this type of behavior in more focused data collection settings.

research report

An Analysis of Travel Characteristics of Carless Households in California

Publication Date

May 1, 2018

Associated Project

Author(s)

Jean-Daniel Saphores, Suman Mitra

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

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Abstract

In spite of their substantial number in the U.S., the research team’s understanding of the travel behavior of households who do not own motor vehicles (labeled “carless” herein) is sketchy. The goal of this paper is to start filling this gap for California. We perform parametric and non-parametric tests to analyze trip data from the 2012 California Household Travel Survey (CHTS) after classifying carless households as voluntarily carless, involuntarily carless, or unclassifiable based on a California Household Travel Survey question that inquires why a carless household does not own any motor vehicle. We find substantial differences between the different categories of carless households. Compared to their voluntarily carless peers, involuntarily carless households travel less frequently, their trips are longer and they take more time, partly because their environment is not as well adapted to their needs. They also walk/bike less, depend more on transit, and when they travel by motor vehicle, occupancy is typically higher. Their median travel time is longer, but remarkably, it is similar for voluntarily carless and motorized households. Overall, involuntarily carless households are less mobile, which may contribute to a more isolated lifestyle with a lower degree of well-being. Compared to motorized households, carless households rely a lot less on motor vehicles and much more on transit, walking, and biking. They also take less than half as many trips and their median trip distance is less than half as short. This study is a first step toward better understanding the transportation patterns of carless households.

Related Publications

published journal article

How do they get by without cars? An analysis of travel characteristics of carless households in California

policy brief

Travel Varies Greatly Between Voluntary Versus Involuntary Carless Households in California

research report

Do Compact, Accessible, and Walkable Communities Promote Gender Equality?

Publication Date

March 1, 2018

Associated Project

Do Compact, Accessible, and Walkable Communities Promote Gender Equality?

Author(s)

Ashley (Wan-Tzu) Lo, Douglas Houston

Areas of Expertise

Safety, Public Health, & Mobility Justice Travel Behavior, Land Use, & the Built Environment

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Abstract

Directing growth towards denser communities with mixed-use, accessible, and walkable neighborhood design has become an important strategy for promoting sustainability, but few studies have examined whether compact development strategies could help reduce within-household gender disparities in spatial behavior by increasing accessibility. The research team analyzed the spatial behavior of heterosexual married couples in Southern California based on the 2012 California Household Travel Survey and found that households living in areas with greater regional accessibility and neighborhood walkability have smaller, more centered, and more compact activity spaces overall compared to households in less compact areas, and that married pairs living in more accessible areas have greater equality in the size and centeredness of their activity spaces. Results support the hypothesis that compact development provides married couples greater flexibility in how they divide household out-of-home activities by making destinations more convenient. Future research and planning efforts should carefully consider which aspects of compact, accessible development are most effective for a given local context.

Related Publications

policy brief

Compact, Accessible, and Walkable Communities Help Support Gender Equality

research report

State-Level Strategies for Reducing Vehicle Miles of Travel

Publication Date

September 1, 2017

Associated Project

State-Level Strategies for Reducing Vehicle Miles of Travel

Author(s)

Michelle Byars, Susan Handy, Yishu Wei

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

View research report

Abstract

California adopted a statewide target of reducing greenhouse gas emissions to 40% below 1990 levels by 2030. To meet these goals, the state must achieve a 15 percent reduction in total travel by light-duty vehicles by 2050 compared to expected levels. Under current state policies, reductions of this magnitude are likely. This report explores the evidence for strategies to reduce vehicle miles of travel in pricing, infill development, transportation investments, and travel demand management programs. For each category, the report outlines programs from other states that, if adopted, have the potential to reduce (vehicle miles traveled) VMT and thus greenhouse gas emissions.

Related Publications

policy brief

State-Level Policies for Reducing Vehicle-Miles Traveled

research report

Transit Investment Impacts on Land Use Beyond the Half-Mile Mark

Publication Date

June 1, 2017

Associated Project

Transit Investment Impacts on Land Use Beyond the Half-Mile Mark

Author(s)

Ashley (Wan-Tzu) Lo, Douglas Houston, Jae Hong Kim, Jaewoo Cho, Nalia Shareem

Areas of Expertise

Public Transit, Shared Mobility, & Active Transportation Travel Behavior, Land Use, & the Built Environment

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Abstract

This project examines the impacts of light rail transit investments on broader vicinity areas in Los Angeles County. This project found that the land use impacts of public transit investments are not necessarily confined to the half-mile boundary around station areas, although substantial variation exists by transit line. While the areas beyond the half-mile mark were often excluded from conventional transit-oriented planning processes, these areas show a distinct pattern of land use transformation. Areas beyond the half-mile mark had a higher rate of development for several urban purposes, particularly after a few years have elapsed since the opening of nearby transit lines/stations.

Related Publications

policy brief

Transit Investments are Having an Impact on Land Use Beyond the Half-Mile Mark

research report

Policy and Literature Review on the Effect Millennials Have on Vehicle Miles Traveled, Greenhouse Gas Emissions, and the Built Environment

Publication Date

June 1, 2017

Associated Project

Policy and Literature Review on the Effect Millennials Have on Vehicle Miles Traveled, Greenhouse Gas Emissions, and the Built Environment

Author(s)

Douglas Houston, Michelle E. Zuniga, Stephen Ritchie

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

View research report

Abstract

Vehicle travel has reduced substantially across all demographics in the 2000s, but millennials or young adults born between 1985-2000 stand out as the group that has reduced vehicle travel the most. This reduction of travel among millennials is known as the millennial effect. This policy and literature review discusses insights from recent policy reports and literature regarding the millennial effect and identifies the prominent themes and gaps in knowledge. The first section reviews existing research on the millennial effect on vehicle miles traveled (VMT). The second section discusses the influence of the built environment on the travel and activities of the millennial generation. The third section highlights scenarios describing the millennial effect’s potential magnitude and identifies topics for consideration in future scenario planning efforts. The final section discusses the uncertainty that exists regarding the future behavior of millennials and their influence on vehicle miles traveled and greenhouse gas emissions.

policy brief

Activity Patterns of Heavy-Duty Vehicles and Their Implications on Energy Use and Emissions

Publication Date

May 1, 2017

Associated Project

Collection of Activity Data from On-Road Heavy-Duty Diesel Vehicles

Author(s)

Kanok Boriboonsomsin

Areas of Expertise

Freight, Logistics, & Supply Chain Travel Behavior, Land Use, & the Built Environment

View policy brief

Abstract

Heavy-duty vehicles comprise a variety of vocations whose distinct operational requirements create different activity patterns. Understanding these differences will allow development of appropriate energy and emission reduction strategies.For instance, many heavy-duty diesel vehicles employ the selective catalytic reduction (SCR) to meet the new 2010 emission standards for nitrogen oxides (NOX). Typically, SCR needs to be at least 200 OC before significant NOX reduction is achieved. Some activity patterns may increase the frequency with which this temperature requirement is not met such as during start-up and idling.Similarly, the electrification of heavy-duty vehicles is a promising pathway for energy independence and emissions reduction but is complicated by the trade-off between battery size and the driving range necessary for specific operating goals. Detailed knowledge of activity patterns can therefore inform what vocational uses of these vehicles are suitable candidates for electrification.

Related Publications

research report

Collection of Activity Data From On-Road Heavy-Duty Diesel Vehicles

policy brief

State-Level Policies for Reducing Vehicle-Miles Traveled

Publication Date

May 1, 2017

Associated Project

State-Level Strategies for Reducing Vehicle Miles of Travel

Author(s)

Susan Handy, Michelle Byars, Yishu Wei

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

View policy brief

Abstract

California has set ambitious goals for reducing its greenhouse gas emissions to 40% below 1990 levels by 2030 and 80% below 1990 levels by 2050. To meet these goals, the state must achieve a 15 percent reduction in total travel by light-duty vehicles by 2050 compared to expected levels. Under current state policies, reductions of this magnitude are unlikely.
Strong empirical evidence supports strategies across four categories that can reduce vehicle miles of travel (VMT) (1) pricing, (2) infill development, (3) transportation investments, and (4) travel demand-management programs. The state can directly implement some of these strategies, particularly pricing strategies, through state-level policies. Others depend on actions by regional and local governments, though state-level policies can encourage their implementation through incentives, requirements, or other mechanisms.