Household Vehicle Holdings and Composition: A Multi-Dimensional Analysis of Body and Fuel Type Choices

Term Start:

June 1, 2026

Term End:

May 31, 2027

Budget:

$75,000

Keywords:

Fleet composition, Travel Demand, Vehicle ownership

Thrust Area(s):

Data Modeling and Analytic Tools, Understanding User Needs

University Lead:

The University of Texas at Austin

Researcher(s):

Chandra Bhat

Household vehicle ownership is the foundation of personal mobility for the vast majority of American families. The number of vehicles a household owns, and the specific types of vehicles in its fleet, determine how household members access employment, healthcare, education, and services, and directly generate the travel demand that shapes roadway utilization, network performance, and infrastructure needs. Accurately representing how households make vehicle fleet decisions is therefore essential for travel demand forecasting, long-range transportation planning, and the design of policies that support reliable and efficient system operations.

While a substantial body of research has examined vehicle holdings, several important gaps remain. Most existing studies treat vehicle ownership as a single aggregate outcome, failing to jointly model the count of vehicles owned alongside the specific body-type and fuel-type composition of the household fleet. Even studies that examine fleet composition, often using the multiple discrete continuous extreme value (MDCEV) modeling approach (Bhat and Sen, 2006; Augustin et al., 2015; Chakraborty et al., 2023), identify only whether at least one vehicle of each type is present, rather than modeling the count of vehicles in each category. This is a meaningful limitation as many households own more than one vehicle of the same body type, and the specific count in each category has direct implications for household mobility capabilities and system-level demand generation. Further, existing studies do not allow for a direct effect of total fleet size on preferences for specific vehicle types. This is an important consideration because a household adding a second or third vehicle faces a fundamentally different choice context than one purchasing its first, and the body type preferred as a secondary addition to an existing fleet may differ substantially from a household’s primary vehicle choice.

By quantifying how total fleet size directly influences body-type preferences, the project will improve the accuracy of vehicle availability estimates used in household-level travel demand analysis, supporting more reliable forecasts of trip generation, vehicle utilization, and peak-period demand. Together, these contributions will improve the reliability of transportation forecasting tools and support more effective, evidence-based decision-making for infrastructure investment and long-range system planning.

Project scope

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