You only have access to deleting the driver. You are not allowed access to the driver packages that are installed with the operating system located in \windows\system32\driverstore\filerepository.
For print drivers that are used for a printer connection, the user that has created the connection does not need to logged onto the machine to cause the "Driver in use" error.
You can have all the users on the machine log on and delete their existing connections which use the driver, delete the connection information in the registry for each user that has a connection using the driver, or delete the print driver information in
the registry. Any registry modification will require a print spooler service restart.