Graduation Year


Document Type




Degree Name

MS in Civil Engineering (M.S.C.E.)

Degree Granting Department

Civil and Environmental Engineering

Major Professor

Robert Bertini, Ph.D.

Committee Member

Steven Polzin, Ph.D.

Committee Member

Fred Mannering, Ph.D.


Age, Density, NHTS, TNC, Trip Length, VMT


Vehicle miles of travel (VMT) is a key indicator of travel demand in the United States. Since 1995 total VMT and VMT per capita has fluctuated, with notable declines in the late 2000s and accelerated increases in the last 7 years. Since 1995, the National Household Travel Survey (NHTS) has tracked the household share of total VMT to shed light on the demographic and behavioral data behind personal vehicle travel. The household share of VMT, while still a majority, has declined every NHTS year since at least 1995. Meanwhile, household VMT has stagnated around 2.25 trillion miles since the 2001 survey. With such unprecedented travel demand changes, the current transportation technology revolution, and the climate of uncertainty, it is critical to understand why household VMT is changing and how this might affect future roadway demand.

This thesis examines demographic, socioeconomic and behavioral factors that influence VMT, including both factors with existing research and some untraditional factors, using new data and methodologies.