A modular vehicle key device system for controlling vehicle access and operation. The device is formed by joining at least two separable modules, a first key device module containing vehicle access and/or operation authorizing elements, such as a keyless entry transmitter and/or an ignition key, and a module for off-vehicle storage of personal adjustment settings and/or other data. With each use of the modular key device, the data in the storage module is transferred to the vehicle to ensure the operator's settings and information are always present. Separating the storage module from the key device module allows others to operate the vehicle while ensuring the operator's personal data cannot be lost. Separation also enables easy transfer of an operator's settings to a like vehicle. Other embodiments allow the operator to allow vehicle operation by others, such as valets, while limiting use of individual vehicle components, such as radios.