You don’t drive to doctors appointments? Job interviews?
(theeheehee, I’ve got an old Land Cruiser, there's a bit of a friendly rivalry)
And carry a few spares and tools. I bet you do, too.
How long does it take you to fill your tank?
How does any of this need you to know the time right now?
I've never been "stuck in traffic", so the problem has never arisen.
It's quite simple really.
If I want to be somewhere 250 miles away, I know it takes about six hours to drive there. So, in order to get there in time, I leave maybe six and a half hours before I need to be there. If I know the road is going to be busy - quite often where I live there are a lot of tourists doing 30mph with no idea there's anyone else on the road - I'll give it even more time.
Dead easy.