Teste18, allow me to continue the talk in English, so others (lezurdis, I'm looking to you :) )can understand. I followed lezurdis' hint about the bridges/viaduct, and I'm using the SVN snapshot of JOSM, as teste18 hinted. It's easier to use than Merkaartor... Now we've got some nice bridges (viaducts) near Águas Claras, and with JOSM I've also done some beautiful roundabouts.

Teste18, I can attest the outdatedness (if that's even a word) of Yahoo imagery, they were made before we had half of Águas Claras :)

Thank for your help, we'll keep improving the DF map.

Je les aurai, merci beaucoup!

Thanks, I'll try that with Merkaartor.