www.autobahnschweiz.ch gives you an overview of the current building sites on the Swiss Highway network and the expected completion dates.

There seems to be one big site between Lenzburg and Birrfeld and according to the project webpage (http://www.astra.admin.ch/autobahnsc...x.html?lang=de), completion is expected in 2013.

Furthermore between Härkingen und Wiggertal, where the A1 and the A2 overlap, they are extending the road from 4 to 6 lanes, building started in 2011 and is expected to finish in 2014. (http://www.astra.admin.ch/autobahnsc...x.html?lang=de)