Corporate Policy
Body of evidence that lets an auditor reconstruct the history of an expense.
A mileage audit trail includes: date, time, origin, destination, GPS map, distance, per-km rate, business purpose, employee ID, project/cost center, and integrity hash of the receipt. With this data, an auditor (internal, external, or tax) can reconstruct what happened without asking the employee. The more complete the trail, the lower the risk of disallowance.