Hi Taras,
Thank you for your reply.
Under VehicleManager : Settings, I only see "Common Settings" which manages the user permission for adding vehicles... what access permission I am looking for is in the backend, the only user is able to access the vehicleManger from the components menu is "administrator", if I want to grant access to the the special users so they can open the backend management interface, the user has to be in "administrator" group, but I don't want to give the user more permission to manage other modules and plugins, etc...
Please take a look at the enclosed picture which shows what access I can assign to the manager group for component "BreezingForms".