The motorcar, for example, promised unimaginable levels of personal mobility.
比如，汽车曾使我们希望个人出行会方便得让人难以想象。
英语百科
Personal mobility
In Universal Personal Telecommunications (UPT), personal mobility is the ability of a user to access telecommunication services at any UPT terminal on the basis of a personal identifier, and the capability of the network to provide those services in accord with the user's service profile.