Toyota safety sense

Partially. Probably more accurate to say that the car works very smoothly with Toyota Connect.

The car needs an internet connection to get a route. This can be through a home wifi connection before you leave home or if using Wireless CarPlay it will then use the cell phones data connection. You can also use bluetooth tethering but you don't get the iOS apps to display on the head unit. For example Waze on the head unit is much better than Waze on the iPhone.

The internet connection is not important to the built in navigation as you drive unless you need to reroute. I haven't tested this very thoroughly but based on my observations when driving this is the case. For example I park in a garage and Starlink does not work when it can not see the sky. For a couple of minutes before Starlink orients itself I have found I can not send a destination to the navigation nor can I use the voice assistant to search for a destination nor type in a destination with the onscreen keyboard.

In the case of losing the internet while driving (eg driving through a tunnel) I haven't seen the built in navigation stop functioning.

The head unit can also connect to a mobile wifi hotspot. The downside of connecting to a mobile wifi hotspot is that wireless Android and wireless Apple CarPlay use both bluetooth and Wifi at the same time and the car head unit can only have one wifi connection at a time. I keep my car connected to my Starlink Mini and used wired Apple CarPlay. This enables me to use the voice assistant, built in navigation, and Apple CarPlay.

 

So, it turns out that on my Gen 4 Prius Prime with the large multimedia headunit, the traffic info on navigation is most likely coming from the HD radio. You can apparently also receive it from Sirius XM, but I think that requires subscription to that particular service.