Yes. It is possible.
Please refer following link which is using turn by turn directions using google API.
https://itunes.apple.com/us/app/biznavi-gets-you-where-you/id597147565?mt=8
(see last two screen shot of iPad from itunes link)
To achieve it, you have to use Google Direction API which allows us to use upto 8 way points.
After that you will get an array of route including all turn by turn message and lat/long.
Just create a CLRegion of 100 meters (or as per your requirement.) around your current location in locationDidUpdate method. If next point of route array falls within CLRegion, just show a message received in routes array by google API.
I have made above application but it was not updated after uploading to store so it is having old UI and it is not having iPhone 5+ support. Sorry for that but you will find feature you require in this app...