The first place you’ll want to start is in Google Maps—this is where the bulk of the notifications are coming from, especially when you’re already driving (regardless of whether or not you’re using GPS navigation).

In Maps, slide in from the left side of the screen (or tap the three lines in the upper left corner) to open the menu, then scroll down to Settings.

Scroll down this menu until you see Notifications.

You can control pretty much all aspects of the notifications Maps will generate here, but we’re focusing on traffic data, so you want the top option.

There are three options here:

Traffic from nearby events: Road closures, accidents, detours, etc.
Traffic nearby: Traffic jams, backups, etc.
Driving notifications: ETAs to specific locations—usually Home or Work if you have those set.

You can pick and choose here, disable and enable whatever works best for you.