To activate traffic mode in the Windows Maps app just select the traffic icon in the upper right hand corner of the apps window.
You will now see the traffic conditions centered around your current location. Obviously, the best condition is green for a normal flow of traffic but you may also see orange (slow downs) and red (backups/delays).
To see an active traffic camera just click on it and you will see it displayed in the app window.
As you browse traffic cameras the last six you viewed will remain visible under Recently viewed cameras. These choices will remain persistent between uses of the app as well which can be very handy.
Any incidents will be marked and you just click on them to see information about the issue.
You can pin a Live Tile to the Start Screen for quick access to traffic mode in the app.