Whn I am driving or on my bike, I like to play 'Drunk or on the phone?', a game of guessing whether a driver exhibiting the signs of drunk driving is actually drunk or just using their phone while driving.
Same. Tell-tale signals include driving slower than reasonably makes sense. Drifting around the lane. The speed-up / slow-down pattern where they speed-up while they're looking up, then slow down while they're typing. It's infuriating how selfish drivers can be.
It's always the phone.