If you live in one of the selected cities, no application update is needed - you'll be getting live transit updates and alerts immediately.
Real-Time Transit Schedule Updates Now On Google Maps For Android, Desktop, And Mobile
Google announced a new update to Maps that would bring a much sought-after feature for those who use public transit in major cities: real-time updates that provide the whereabouts of busses. No longer will you have to hang out wondering when the bus is actually going to show up, because with the help of Maps, you'll have all of that info in the palm of your hand.
El Goog has teamed up with transit agencies to make this update happen, but there is one downside (for some people, anyway): it's only in four US cities as of right now. The lucky four are Boston, MA; Portland, OR; and San Diego and San Francisco, CA. Goog also threw a couple of European cities in the mix: Madrid, Spain and Turin, Italy.