Do brake booster replacement problems track elevation range from lowest to highest point across states?
Across U.S. states, NHTSA owner complaints about brake booster replacement run higher where elevation range from lowest to highest point is higher, after adjusting for the makes sold in each state. This is an association across states, not proof that elevation range from lowest to highest point causes this repair.
State reports of this repair against elevation range from lowest to highest point, 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 elevation range from lowest to highest point (meters)
How to read it: Each dot is a state. Further right means more elevation range from lowest to highest point (meters); 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 elevation range from lowest to highest point (meters).
What it shows: States with more elevation range from lowest to highest point (meters) tend to sit higher on the chart across 31 states: a pattern in the data, not proof of cause.
Data: USGS, highest and lowest elevations in each state, joined to NHTSA owner complaints, downloaded 2026-10-06 · 31 states. Chart: CalcScrape · calcscrape.com
The 10 states with the most elevation range from lowest to highest point (California, Washington, Arizona, Utah, Colorado, New Mexico, Texas, North Carolina, Tennessee, Virginia): reports of this repair run 18% above what the makes sold there would predict, and 9 of 10 are above expected. The 10 with the least (Florida, Louisiana, Indiana, Illinois, Ohio, Wisconsin, Michigan, Missouri, Minnesota, New Jersey): 1% below, and 5 of 10 are above expected.
Exceptions: Tennessee is among the highest in elevation range from lowest to highest point but reports below expected; Minnesota (22% above expected) is among the lowest but above expected.
Split the states into thirds: the third with the least elevation range from lowest to highest point runs 1% below what the makes sold there would predict, the middle third 1% below, and the third with the most 18% above. Most of the elevation range from lowest to highest point effect sits in the third with the most.
For elevation range from lowest to highest point, after allowing for the 1562 comparisons we ran, luck alone would produce a pattern this strong about 1 time in 16. Take out any single state and the elevation range from lowest to highest point pattern still holds.
Weak spot: compare only states with similar vehicles per household and the pattern keeps about 53% of its strength, so part of it may come from vehicles per household instead of elevation range from lowest to highest point.
For elevation range from lowest to highest point, of the 5 exception states, 1 read the same way for the other parts of the system (so that is the system there, not this repair) and 4 are specific to this repair.
Long mountain grades mean sustained braking, heavy loads on the transmission and driveline, and hotter engines on the climb.