After so many years, Google Maps is coming to the cars of Apple device users thanks to the Apple CarPlay application.
Apple announced earlier in 2018 that apps like Google Maps and Waze would receive CarPlay support with the iOS 12 update.
And from what we can see after the release of the new update, Apple has kept its promise. So, Apple Maps is no longer the only navigation app you can use while driving.
Google Maps doesn't come with Siri support, however, you can use the built-in voice assistant that Google offers. You can even dictate things like streets and addresses, and since Google's technology is already quite advanced, you're not going to have any trouble navigating.

As for Waze, the number one navigation app, it is expected to receive CarPlay support soon. If development goes as planned, Waze will launch with CarPlay support in the coming weeks.
For your information, both Google Maps and Waze already have Android Auto support and can be connected to compatible car displays using an Android phone. However, on iPhones, CarPlay has limited navigation options, making the user experience more difficult.
