Depends on your definition of "traffic."
Stop and go? You won't see that. The worst you'll see is maybe going from stop light to stop light through Stratham. But once you're through the strip mall area, the "traffic" may consist of a dozen or so cars ahead of you all the way through Newmarket to Durham.
I regularly drive to/from Durham and Milford, MA. It takes me 1.5 hrs via 101/108, and coming north, it takes me about 30 minutes from Seabrook to get to Durham.
In comparison, the General Sullivan bridge backs up to the Fox Run Mall, in mostly stop and go until you clear the bridge.