Fixing a Mileage Number Somebody Guessed

Somewhere on your declarations page is an annual mileage figure. For most households it was produced in about four seconds, years ago, by somebody who said "twelve thousand?" into a phone. California's rating rules point to miles driven as one of the primary factors, so that four-second answer has been doing real work ever since.

Why the guess is usually too high

People estimate from their heaviest period. The year with the long commute, the year before the kids moved out, the year of the weekly drive to a relative. Then the commute changed, or a second car arrived and absorbed half the trips, and the figure never moved. In our office, when we actually work the number out with somebody, it comes down more often than it goes up.

Work it out properly — two methods

The odometer method, which is the good one. Photograph the odometer today. Photograph it again in thirty days. Multiply the difference by twelve. That is a real figure with evidence behind it, and thirty days smooths out a single unusual week.

The reconstruction method, if you need a number now:

1. Round-trip commute distance, times the days a week you actually go in, times about 48 working weeks.
2. Add a weekly figure for errands, school runs and everything local.
3. Add the trips you take once or twice a year, counted individually.
4. Add it up honestly. Do not round upward "to be safe" — that is exactly the habit that produced the wrong figure originally.

Do this per vehicle. A two-car household splits its miles between them, and rating each car as though it carries the whole household's driving is a common and expensive error.

Where the evidence lives

• Dated odometer photographs.
• Service records — oil changes and inspections list mileage with dates, and two of them bracket a real interval.
• Smog check records, which also carry an odometer reading.

Reporting the correction

Call the carrier, say you want the annual mileage corrected on a specific vehicle, give the figure and offer the evidence. Ask two questions: whether the change applies from today or at renewal, and whether anything else on the vehicle line should change with it — the use code, for instance, if a commute has genuinely ended.

The rule that matters most

Correct it to the truth, in whichever direction the truth lies. A figure lowered below reality is a misstatement on an application, and the place that surfaces is at a claim. If your driving went up because you changed jobs, report that too. The purpose here is accuracy, and accuracy happens to favor most households.

Send us your real annual figure per vehicle and we will price it as it actually is.