[Andy Howell]

I would agree with Doug.

I live in a relatively noisy and busy area but I don't have problems with small condensers picking up unwanted noise. But then I don't know how noisy your road is or how close your room is to the road.

I would try and analyse what is going on first.

I recommend renting some mics for the weekend, or borrowing some if you can. Rather than a formal rental you might find your local store is more helpful in allowing you to test mics in your price range.Z

Test recordings will allow you to not only get a feel for the road noise but as Doug suggests get a feel for your room's natural acoustics.

If and when you find a solution that you are happy with the portable gobos/screens might be a very good idea.

Don't go spending of money without doing some basic testing!