# The Next Generation of Travel Statistical Analysis

Evelyn Blumenberg, PhD

Brian D. Taylor, PhD, FAICP

Michael Smart, PhD

Kelcie Ralph

Madeline Wander

Stephen Brumbaugh

Institute of Transportation Studies

Lewis Center for Regional Policy Studies

UCLA Luskin School of Public Affairs

3250 Public Affairs Building

Los Angeles, CA 90095-1656

310-903-3305, 310-903-3228

eblumenb@ucla.edu, btaylor@ucla.edu

PDF Version 2.8MB

## Acknowledgments

We conducted this research with funding from both the University of California Transportation Center and the U.S. Federal Highway Administration (the latter through a contract with Jack Faucett Associates, Incorporated). The authors are grateful for this support. All errors or omissions are the responsibility of the authors, and not the funding organizations.

## Table of Contents

- A. Overview
- B. What We Did
- C. What We Find in a Nutshell
- D. What We Find in Each of Our Four Analyses

- A. Descriptive Data
- B. Travel to and from School
- C. Alternative Modes of Travel
- D. Urban Form and Travel Behavior
- E. Gender Differences in Travel Behavior
- F. Mobility and Safety
- G. Methodological Issues
- H. Conclusion

- A. Unemployment Rates
- B. Household Structure
- C. Use of Technology
- D. Graduated Driver's Licensing Regulations

- A. Introduction
- B. Methodology
- C. Descriptive Statistics
- D. Cross-Sectional Models and Model Results
- E. Quasi-Cohort Model Results
- F. Conclusion: What Explains PMT among Teens, Young Adults, and Adults?

- A. Introduction
- B. Methodology
- C. Descriptive Statistics
- D. Cross-Sectional Model and Model Results
- E. Income and Auto Availability Submodels
- F. Quasi-Cohort Models and Model Results
- G. Conclusion: Youth, Activities, and Trips

- A. Methodology
- B. Who are Youth Workers and How Do They Travel?
- C. Cross-Sectional Commute Mode Model Results
- D. Variables of Interest
- E. Cross-Sectional Results by Commute Mode
- F. Quasi-Cohort Model Results
- G. Conclusion: Commute Mode Findings

- A. Introduction
- B. Methodology
- C. Descriptive Statistics
- D. Cross-Sectional Model Results
- E. Quasi-Cohort Model and Model Results
- F. Conclusion: Social Trip Mode

- A. What Explains PMT among Teens, Young Adults, and Adults?
- B. What Explains Patterns of Activities and Trips among Youth and Adults?
- C. How Do Commute Mode Choice Patterns Compare between Youth and Adults?
- D. How Do Social/Recreational Mode Choice Patterns Compare Over Time?

## List of Tables

- Table 1: Summary Table: PMT and Variables of Interest (1990, 2001, and 2009)
- Table 2: Summary Table: Number of Trips and Variables of Interest (1990, 2001, and 2009)
- Table 3: Summary Table: Commute Mode and Variables of Interest (1990, 2001, and 2009)
- Table 4: Social Mode and Variables of Interest (1990, 2001, and 2009)
- Table 5: Number of Person Records per Cohort and Data Year
- Table 6: Summary of Independent Variables
- Table 7: Insurance Institute for Highway Safety Graduated Drivers License Rating Scheme
- Table 8: Data Availability by Year (1990, 2001, and 2009)
- Table 9: Number of States per License Rating (1990, 2000, and 2008)
- Table 10: Percent of Drivers by Age Group and Strength of Licensing Regulation (1990, 2001, and 2009)
- Table 11: Vehicle Miles Traveled as a Percentage of PMT by Age Group (2001 and 2009)
- Table 12: Average PMT by Driver Status, Age Group and Year (1990, 2001, and 2009)
- Table 13: PMT by Age Group and Strength of Licensing Regime (1990, 2001, and 2009)
- Table 14: PMT by Employment and Age (2009)
- Table 15: PMT by Web Use and Age (2009)
- Table 16: PMT by Year and Boomerang Status of Young Adults 19–26 (1990, 2001, and 2009)
- Table 17: Driver Model of PMT, Excluding Licensing (1990, 2001, and 2009)
- Table 18: Licensing Model of PMT, Excluding Driver Status (1990, 2001, and 2009)
- Table 19: Quasi-Cohort Model of Log-Transformed PMT (1990, 2001, and 2009 combined)
- Table 20: Summary Table: PMT and Variables of Interest (1990, 2001, and 2009)
- Table 21: Assessing Model Fit: PMT Models (1990, 2001, 2009 and Cohort)
- Table 22: Structural Equation Models of Number of Daily Activities for Youth (15–26) and Adults (27–61), (1990, 2001, and 2009)
- Table 23: Direct and Indirect Effects of Income on the Log-Transformed Number of Daily Activities, Youth and Adults (1990, 2001, and 2009)
- Table 24: SEM Quasi-Cohort Model of the Log-Transformed Number of Activities Per Day
- Table 25: Summary Table: Number of Trips and Variables of Interest (1990, 2001, and 2009)
- Table 26: Major Trip Purpose Categories
- Table 27: Average Daily Trips by Age Group (1990, 2001, and 2009)
- Table 28: Variables in Commute Mode Models (1990, 2001, and 2009)
- Table 29: Worker Status of Respondents (1990, 2001, and 2009)
- Table 30: Percent Working Within Each Racial/Ethnic Group by Year (1990, 2001, and 2009)
- Table 31: Commute Mode: Carpool Relative to Drive Alone (1990, 2001, and 2009)
- Table 32: Commute Mode: Transit Relative to Drive Alone (1990, 2001, and 2009)
- Table 33: Commute Mode: Bicycle Relative to Drive Alone (1990, 2001, and 2009)
- Table 34: Commute Mode: Walk Relative to Drive Alone (1990, 2001, and 2009)
- Table 35: Quasi-Cohort Logit Model for SOV Use for Journey to Work
- Table 36: Assessing Model Fit: Commute Mode Models (1990, 2001, and 2009)
- Table 37: Summary Table: Commute Mode and Variables of Interest (1990, 2001, and 2009)
- Table 38: Social Travel Mode: Carpool Relative to Drive Alone (1990, 2001, and 2009)
- Table 39: Social Travel Mode: Transit Relative to Drive Alone (1990, 2001, and 2009)
- Table 40: Social Travel Mode: Bicycle Relative to Drive Alone (1990, 2001, and 2009)
- Table 41: Social Travel Mode: Walk Relative to Drive Alone (1990, 2001, and 2009)
- Table 42: Cohort Poisson Model of the Share of Social Trips taken by SOV
- Table 43: Summary Table: Social Mode and Variables of Interest (1990, 2001, and 2009)
- Table 44: Summary Table: PMT and Variables of Interest (1990, 2001, and 2009)
- Table 45: Summary Table: Number of Trips and Variables of Interest (1990, 2001, and 2009)
- Table 46: Summary Table: Commute Mode and Variables of Interest (1990, 2001, and 2009)
- Table 47: Summary Table: Social Mode and Variables of Interest (1990, 2001, and 2009)
- Table 48: Number and Percentage of Trips by Length and Survey Year
- Table 49: PMT by Employment Status and Age Group (1990, 2001, and 2009)
- Table 50: PMT Cross-Sectional Model – Standardized Coefficients

## List of Figures

- Figure 1: PMT Breakpoints, 2001 NHTS
- Figure 2: PMT Breakpoints, 2009 NHTS
- Figure 3: Ages of Cohorts Included in the Model by Data Year
- Figure 4: Unemployment Rates by Age Group (1948-2012)
- Figure 5: Percent Working By Age and Year (1990, 2001, and 2009)
- Figure 6: Percent of Young People (19–26) Living At Home with Parents (1990, 2001, and 2009)
- Figure 7: Percent of Youth Who Live at Home with Parents by Age and Year (1990, 2001, and 2009)
- Figure 8: Use of Technology by Age (2001 and 2009)
- Figure 9: Percent Drivers by Age, 15–22 (1990, 2001, and 2009)
- Figure 10: Percent Youth with Drivers License by Age when License Restrictions are Lifted (2009)
- Figure 11: Percent Drivers by Licensing Regime and Year, Teens 15–18 (2001 and 2009)
- Figure 12: Personal Miles Traveled by Age Group and Year (1990, 2001, and 2009)
- Figure 13: Vehicle Miles Traveled as Percentage of PMT by Age (2001 and 2009)
- Figure 14: Sex Differences in PMT by Age and Year (1990, 2001, and 2009)
- Figure 15: Independent Effect of Cohort on PMT, Controlling for Other Variables
- Figure 16: Number of Daily Trips (2009)
- Figure 17: Simplified Overview of Structure Equation Models (SEMs)
- Figure 18: Mean Number of Trips by Age (2009)
- Figure 19: Mean Number of Daily Trips by Age and Year (1990, 2001, and 2009)
- Figure 20: Mean Number of Daily Trips by Age and Year (1990, 2001, and 2009)
- Figure 21: Difference in Trip-Making by Age (2001 to 2009)
- Figure 22: Household Income and Trip-Making (2009)
- Figure 23: Auto Availability and Trip-Making (2009)
- Figure 24: Overview of Expected Effect of Income on Trip-Making, Youth and Adults, Household Income of $10,000 Base (=1.0) (1990, 2001, and 2009)
- Figure 25: Estimated Independent Effect of Age on Trip-Making (age 15=0)
- Figure 26: Combined Direct and Indirect Effects on Trip-Making of Birth Cohort
- Figure 27: Average Daily Trips by Age Group (1990, 2001, and 2009)
- Figure 28: Worker Status by Age and Year (1990, 2001, and 2009)
- Figure 29: Percentage of Youth Working by Age and Year (1990, 2001, and 2009)
- Figure 30: Percentage of Working Youth by Race/Ethnicity and Year (1990, 2001, and 2009)
- Figure 31: Unemployment by Race/Ethnicity, 1990-2011 (U.S. Department of Labor)
- Figure 32: Commute Mode for All Workers (1990, 2001, and 2009)
- Figure 33: Commute Mode for Youth (1990, 2001, and 2009)
- Figure 34: Commute Mode for Adults (1990, 2001, and 2009)
- Figure 35: SOV Independent Effect of Cohort, Controlling for Other Variables
- Figure 36: Average Daily Social Trips by Age Group (1990, 2001, and 2009)
- Figure 37: Percentage of Social Trips by Age Group (1990, 2001, and 2009)
- Figure 38: Social Trip Mode by Age Group and Year (1990, 2001, and 2009)
- Figure 39: Expected Percentage Change in Share of Social Trips Made by SOV by Cohort