PROJECT NUMBER: PSR-26-26

FUNDING SOURCE: Caltrans

TOTAL COST: $227,018

PERFORMANCE PERIOD: JANUARY 2027 - JUNE 2028

Project description

Hybrid work changed where people spend the weekday, and with it two things that used to move together: the trips a household makes for itself, and the trips made to the household by others. California lacks causal evidence on either. Studies disagree on whether hybrid workers make more midday and discretionary trips or fewer, and on how much of that travel has been replaced by deliveries.

On July 1, 2026, California raised the required in-office days for state employees from two per week to four, affecting a workforce that makes up roughly one in ten working residents of the six-county Sacramento region and one in five in the most concentrated neighborhoods. The project uses this dated change to measure what followed on two fronts: the travel households make, and the commercial vehicle activity serving them at home. It traces how employment, household and activity locations shifted over the past decade, identifies where those trends broke, and measures the change on both fronts within one framework, the Household Presence Analysis Framework, which applies common spatial units, time periods, neighborhood exposure measures and one causal design across passenger travel and residential commercial vehicle activity. The two campuses develop the framework together; UC Davis leads the commercial vehicle side and USC the household travel side, and the two sides are read against each other to quantify the substitution between personal trips and deliveries.