Abstract: Described are various embodiments of a system for releasably storing keys to a vehicle, the system comprising a plurality of independently accessible storage units, each said independently accessible storage unit configured to be unlocked independently of one another based on digital unlocking signals that trigger unit-specific lock mechanisms; a communications bus for interfacing with a pre-existing independent third-party data storage facility; one or more user interface devices for receiving user-identifying information about users; local digital data storage for storing locally-stored information relating to one or more of the following: user-identifying information, keys, storage units; a processor, being communicatively coupled to said local digital data storage, said communications bus, and said multi-unit storage facility, said processor configured determine whether a given user is authorized to access a given storage unit based on said user-identifying information and transmit a digital unlocking sig