The Relationship Between Income and Personal Vehicle Fuel Efficiency and Associated Equity Concerns for the Fuel Tax (SWUTC/11/161007-1)

The fuel tax, which is assessed on the physical amount of fuel purchased by the consumer, is the primary means of funding roadway development at the state and national level. However, because it is assessed on a gallon basis, drivers of vehicles with a low fuel efficiency pay more per mile for use of the roadway than drivers of more fuel efficient vehicles. If there is a relationship between fuel efficiency and income, such that lower income drivers are more likely to drive a low fuel efficiency vehicle, then the equity of the fuel tax is in question. In this study, researchers analyzed over 350,000 vehicle registration records from around the State of Texas to determine if areas with a lower median income had a higher distribution of low fuel efficiency vehicles. Researchers found that vehicles registered in lower income areas tended to have lower average fuel efficiencies than vehicles registered in areas with mid-range and higher income. Lower income areas and rural areas were also more likely to have a higher percentage of class 35 vehicle registrations, usually larger light duty pickup trucks and sport utility vehicles, which tend to have lower fuel efficiency.