Which document is referred to as a log book for vehicle usage?

The document referred to as a log book for vehicle usage is the DS 9. This form is specifically designed to record information about the operation and maintenance of vehicles. Such details often include the date, time, mileage, and any other relevant notes regarding the vehicle's usage. Keeping an accurate log ensures compliance with regulations, helps in tracking vehicle performance, and maintains accountability for vehicle use, which is crucial for sanitation enforcement and similar sectors.

The other options do not serve the same purpose. They may relate to different forms or documentation used within various operational contexts but are not specifically designated as the log book for vehicle usage. Understanding the specific functions and purposes of various documentation types is vital in ensuring compliance and effective management of resources within the sanitation enforcement field.