Huh. I know for sure here (DC metro area) Google's navigation definitely takes traffic into account both for time estimates and routing. It'd be pretty useless otherwise: traffic is pretty much the major component of travel time for many/most trips.

I haven't used Google Maps in a while, but I remember joking that it gave time estimates as if everyone was driving Ferraris: they always seemed to be extremely optimistic.

The OP's comment about Google's directions often giving you things like unprotected left turns across major roads matches my experience with Waze, so I wonder if Google is pulling in more data/algorithms from them now. I know lots of people love (loved?) Waze and I used to be one of them, but I eventually just couldn't handle how almost every ride with Waze had become the algorithmic equivalent of your crazy uncle saying "I know a shortcut. Trust me."

It seemed to take current conditions into account - route around areas that are already bad but it didn’t seem to account for typical volume at the time you’ll likely be somewhere. We used to get these routes showing normal speeds all the way through NYC, even though it was obvious that conditions would be different by the time we go there.

I’d hope they’ve improved it since then. I mostly stopped using it because I’d get tons of unprotected left turns on major roads or zig-zag routes through neighborhoods and it just wasn’t worth having to deal with that to save a minute.