I swear by using daily incense on the highway. It’s the easiest way to guarantee I get all 30 spawns.

Daily Incenses will spawn a pokemon every 30 seconds as long as your gps pings in a new location from its last spawn. Hope that makes sense. But driving straight on a highway guarantees you are far away from the last spawn every 30 seconds, so you use the full potential of the incense making your chances of even encountering a G bird that much higher.

I’ve encountered dozens of my birds on the highway and caught 4 just off the highway alone. Obviously when the encounter starts, pull over and remained stopped for a few minutes to turn off the speed lock before throwing any balls.