Asked to declare political party before voting. Is that normal in a general election?

I was putting my vote in Tuesday and before I could show my ID and get my ticket to vote, I was asked to declare whether I was Republican or Democrat. I was then put in a line going to the "side" of the party I declared. Why have all the secrecy of the blinders if everyone is aware of which way you are likely to vote? I have had this happen in a mid-term election, but never general. Is this proper procedure? It was uncomfortable to say the least.