Electoral, Demographic, and Environmental Predictors of Support for a Transportation Sales Tax in San Diego County

• In Event: Tax Policy and Politics

Abstract

Introduction: Despite the well-documented benefits of increasing access to public transportation, financing such changes presents challenges with local transportation sales tax (LTST) measures being a common approach. Given their place on the ballot, studying LTSTs may also provide insights into electoral support for public transportation that could be used to better position future measures.

Purpose: This research aims to explore the cross-sectional associations of precinct-level voting outcomes on San Diego County Measure G in the 2024 General Election and selected electoral, demographic, and environmental variables.

Methods: Independent variables of interest included political party, socioeconomic deprivation (a composite variable derived from census demographics related to concentrated disadvantage), mean commute time, National Walkability Index scores, and other local sales tax support for a subsample with available data. Election results at the precinct level were retrieved from the San Diego County of Registrars and spatially joined to dasymetrically interpolated independent variables. Analyses were conducted at the precinct level using ordinary least squares (OLS) regression, spatial lag, and spatial error models.

Results: In models both excluding (n=1756 precincts) and including (n=1169 precincts) local sales tax support and spatial lag models (R2=0.60 and 0.71) had superior fit to non-spatial approaches (R2=0.56 and 0.67). Only mean commute was not statistically significant (p=0.05) across all models. Percent Republican was the strongest predictor of support for Measure G (b=-0.405 to -0.420), followed by support for other sales taxes (b=0.230), socioeconomic deprivation (b=0.024 to 0.034),  and walkability (b=0.002 to 0.003).

Conclusion: These preliminary analyses are largely consistent with previous research related to political party support for taxes. Independent of political party and other sales tax support, socioeconomic deprivation and neighborhood walkability were associated with precinct-level support for a LTST in San Diego County. These findings may challenge assumptions about the motivations behind LTST opposition and raises questions about how voting dynamics may reinforce or resist transportation inequities.

Author

• Jacob Carson, San Diego State University
  Presenting Author