Google Maps for iOS is a pretty big success, there's no arguing that idea by this point. The app soared to the top of the iTunes charts within seven hours of
release, it saw 10 million downloads in its first two days of release, and the critics love it. Of course, Google Maps still has the trouble that it isn't integrated with iOS like the stock Apple Maps. Well, here's a quick and easy how to for using Siri to get Google Maps directions.
The best part of the trick is that it will work on any iOS device that has both Siri and Google Maps, and doesn't require jailbreaking. All you have to do is tag your directions request to Siri with the phrase "via transit", and Google Maps will pop up as an option to give you those directions, because Apple Maps can't. Once you're in, you can then switch the mode of travel to driving or walking if need be.