[telrod11]

I use "OK Google" for dialing when I'm driving, and it's really annoying to get "Can't Reach Google At The Moment", while doing this, because I'm tied to a WiFi connection, that can't authenticate.

This is especially bad for me, as I get AT&T WiFi, and Xfinity WiFi.

Anyone have a solution? I don't want to necessarily have to remember to turn off WiFi every time I get in the car. Also, I rent a lot of cars, so the solution has to be embedded into the phone, not an NFC, or other localized solution...

[KCAndroid1]

Depending on your phone and OS, check the Advanced settings in your Wifi and see if you can tell it to not automatically scan for/connect to WiFi. Alternatively, there are a variety of apps that you can set up to instruct your phone which features to turn on or off in different situations, from the full featured and complicated (like Tasker) to the simple (WiFi Matic).

[Rukbat]

Automate — automatic tasks and IF by IFTTT (simpler) and Tasker will all do it. I use Tasker, and "trigger when connected to a certain Bluetooth signal" is and easy state (BT connected) to do things (like disable wifi) with.