After Maps Navigation, Google now brings Transit Navigation to Google Maps app, and like before, it’s the Android users who get the first taste of it. And unlike maps navigation, transit navigation is available in more than 400 cities world wide right from the launch. Transit Navigation (requires an Android 2.1 or above with Google Maps 5.7 app) makes use of the public transport system timings (with their partnership) and gives you a stop-by-stop navigation, whether you are travelling in a local bus or a metro train.
You can schedule your travel by inputting your destination and the app brings up the list of available buses/trains (including the fares) that are to arrive soon. You can chose any one and once you get in to that bus/train, the transit navigation moves along with the bus/train and informs you about all the stops that come before your destination arrives (if you want to know, that is). But more importantly, it will inform you when to get down. If you should catch a connecting vehicle, the app informs that too.
In India, you can use the Transit Navigation with Bangalore Metropolitan Transport Corporation, Chennai MRTS, Delhi Metro and Kolkata Metro. If you don’t stay in any of these cities or don’t use the mentioned transport systems, you can still use the transit navigation (a half-baked one). For example, here in Mumbai, when I use transit navigation, I get the list of buses with numbers that are next to arrive. But this information is not complete since it asks me to wait for 30 minutes to get in to a bus when I already got in to a bus.
So, basically, for other major cities, it is a work in progress.
Update: This is now fully working for Mumbai and also Hyderabad. I could use the app to see when the next bus arrives and also accurately travel along with the bus and get down at the station that I wanted to.