I am affraid jregieng has older information. Starting on October 2010 exam, not only you have to select your field, you also have to select which depth exam you want to take when you register with NCEES. That is what I did. In fact during the registration process it states clearly that during the afternoon depth, you will be provided booklet for only the subject that you registered for. So, if you registered for Geotech, your afternoon booklet will have only Geotech problems....
As far as which depth exam to select, I have about four years of experience similar to yours. Currently I work on structures with bridge emphasis. However, when I looked at the exam spec for the structures exam, I saw a lot of code related with ACI, ASCE, ..... And I don't have a building experience. So, it was between Transportation or Geotech. However, Since I work in bridges, a third or more of what I do is Geotech. So, it was closer and the spec for the geotech looked more fitting to me.
Several of my coworkers who did the Geotech exam swear by Das books and the Navfac DM 7.01 and 7.02. So, I downloaded the manuals and printed them. I am working on the problems on Das books as the Cerm material seems inadequate for the afternoon Geotech. However, I use CERM extensively for preparation for the morning portion.
B