One website for everybody
Why segregate users from the US (waze.com) and the rest of the world? (world.waze.com). Bet a ton of people try to use Waze on the web, check waze.com instead of world.waze.com, see nothing, and say "it doesn't work, screw it".
I imagine the separation is needed because of traffic volume concerns or something. But in that case, waze.com should redirect you to the right map depending on your IP, or if you're logged in, on your stated location. And you should have "US Map" "Rest of the world" links on the web livemap you can click to switch from one to the other.

Thank you for your suggestion! As you may already know, a live map is available as a web version, which you can use to see real time traffic reports. Search for Waze live map.