Do parking brake repair problems track median household income across states?
Across U.S. states, NHTSA owner complaints about parking brake repair run higher where median household income is higher, after adjusting for the makes sold in each state. This is an association across states, not proof that median household income causes this repair.
State reports of this repair against median household income, one dot per stateEach dot is a state: how much more (or less) than expected this repair is reported there, adjusted for the makes sold in the state, against its median household income (dollars)
How to read it: Each dot is a state. Further right means more median household income (dollars); higher up means more complaints for this repair than expected (1.0 is average). If the dots climb to the right, reports of this repair rise with median household income (dollars).
What it shows: States with more median household income (dollars) tend to sit higher on the chart across 42 states: a pattern in the data, not proof of cause.
Data: U.S. Census Bureau, American Community Survey 5-year 2019-2023 (B19013), joined to NHTSA owner complaints, downloaded 2026-10-06 · 42 states. Chart: CalcScrape · calcscrape.com
The 10 states with the most median household income (Maryland, Massachusetts, New Jersey, Hawaii, California, New Hampshire, Washington, Connecticut, Colorado, Utah): reports of this repair run 9% above what the makes sold there would predict, and 10 of 10 are above expected. The 10 with the least (Mississippi, West Virginia, Arkansas, Louisiana, Alabama, New Mexico, Kentucky, Oklahoma, South Carolina, Tennessee): 5% below, and 3 of 10 are above expected.
Exceptions: New Mexico (27% above expected) is among the lowest but above expected.
Split the states into thirds: the third with the least median household income runs 5% below what the makes sold there would predict, the middle third 1% below, and the third with the most 8% above. It steps up steadily.
For median household income, after allowing for the 1562 comparisons we ran, luck alone would produce a pattern this strong about 1 time in 8. Take out any single state and the median household income pattern still holds.
Weak spot: compare only states with similar cost of living index and the pattern keeps about 0% of its strength, so part of it may come from cost of living index instead of median household income.
For median household income, of the 5 exception states, 2 read the same way for the other parts of the system (so that is the system there, not this repair) and 3 are specific to this repair.
Lower income means older cars kept longer and repairs put off until a part fails, which changes which repairs owners report.