When navigating with your application, there may come a point in time where you see a reference to a time restriction. With the apps that have the feature, this will alert you of any potential routes that are subject to time limitations. For example, it may alert you of a time restriction that the bridge you are planning to pass is closed from 12:00 am to 3:00 am. This allows you to plan your trip accordingly to avoid any unnecessary speed bumps.
MapQuest users may have run into this term before and MapQuest, in specific, allows you to check a box for timed restrictions to avoid inconveniences.