A driver has ultimate responsibility for where they drive their car, that’s not up for debate.
Google is providing guidance, sure, but the driver, by virtue of being present, having eyes and a brain, and controlling the fucking vehicle is the one responsible for where the vehicle goes.
You may have a (very good) point if this was a self driving car and Google was partially or wholly responsible for the actual motion of the vehicle.
But that’s not what happened.
Google’s guidance is nothing more than them saying, “Based on our data, this is the route we think you should take.” Obviously the driver has better data on local conditions than Google.
That being said, local authorities are to blame for improper signage and safety features. While Google isn’t responsible for road conditions and safety, some government or another absolutely is, and they are absolutely a valid target for a lawsuit, as they should be.
That you think Google shoulders blame in this is actually kind of a sad commentary on how some of society views personal responsibility.