The producer is responsible for everything that goes in the newscast...compiling reporters' stories and building them into the rundown, writing "voice overs", which are stories the anchor merely reads while the video is rolling, and finding voice overs from the network feed to run. Probably what happened here is some dumba** know nothing 25 year old who got their job at network because of nepotism, didn't think to check the date on the traffic jam story, because they needed a story to fit the international news segment, and that one fit the bill.
Anchors, like Diane Sawyer, are nothing more than talking heads. If you can get them to read their scripts before they go on the air, you're lucky. Their expertise is with filling time, and either speeding up or slowing down their delivery as the producer talks in their IFB (earpiece) from the control room, keeping them apprised of how much time is left before the next commercial break. Not that the anchors listen to the producer...they're far more important, you know.
In short, no one in the newsroom, except for a few grizzled old editors that people don't listen to anyway, know anything about what's actually going on. The FReeper who said the only real journalism going on these days are blogs and the foreign press, is spot on right.
Scouts Out! Cavalry Ho!
I call them news readers, no more no less.