1. Book transfer: When the library cooperates with other libraries and needs to transfer or borrow specific books, it may send a car to pick up the books.

2. Document delivery: When important documents or documents need to be delivered between different departments or branches of the library, vehicles may be sent for delivery.

3. Extension of library services: In order to provide better services, some libraries will carry out mobile libraries or direct delivery services, and need to send cars to specific locations to provide book lending services.

4. Support for large-scale activities: Sometimes the library may hold large-scale activities, such as reading parties and lectures, and it is necessary to send cars to transport relevant books and materials to the event site.

It should be noted that the specific reasons for the library to send or use cars may be different due to geographical factors, library scale, service scope and other factors. The specific situation needs to be determined according to the actual situation.