In what scenario will the master log be retained longer than one year?

The master log is retained longer than one year primarily when a vehicle has been involved in an accident. This is because accidents often lead to legal implications and investigations that require thorough documentation. Retaining the master log helps in tracking the vehicle's history, maintenance, and operational details that may be pertinent during claims or inquiries.

When a vehicle is part of an accident, having detailed records for reference can be essential for insurance purposes and to ensure accountability regarding the vehicle's condition and any repairs necessary. This retention policy aims to maintain comprehensive documentation until all related issues, such as legal matters or repair claims, are fully resolved.

In contrast, other scenarios such as a vehicle being taken out of service, registered under multiple operators, or scheduled for upgrades do not carry the same legal and operational complexities that necessitate extended record-keeping. These situations typically do not impact the vehicle's history in a manner that would require a prolonged retention of the master log beyond the standard one-year timeframe.