This repo contains a Python function that will convert encoded polyline strings (as returned by the Google Maps API) into a list of lat/lon pairs. If you have arcpy, you can pass the steps object (APIresponse['routes'][0]['legs'][0]['steps']) to convert_to_shapefile() and it will create a polyline shapefile based on your route.

decode_polyline() is a direct port of Mapbox's JavaScript decode function which is in turn based on the official Google document.

To decode a polyline string into a list of lat/lon pairs, use decode_polyline():

decode_polyline('azljFjss{S?oA?kB')
>>> [(38.57329, -109.55078), (38.57329, -109.55038), (38.57329, -109.54984)]

To convert a Maps API response to a shapefile, use convert_to_shapefile():

# Get directions as JSON from the Maps API
APIresponse = get_google_directions('grand junction, co', 'moab, ut')

# Create shapefile based off the returned route
convert_to_shapefile(APIresponse['routes'][0]['legs'][0]['steps'], r"C:\routes\route.shp")
>>> 'C:\\routes\\route.shp'

It's pretty straightforward. I couldn't find an existing Python implementation when I looked so I decided to port one.