I have a 2002 Insight as well, and I have found that there are two situations where I would get MPG like yours:
1. Driving like a bat out of hell on freeways (constantly 80+
MPH). I would get mileage in the upper 40's. How fast are you going on freeways?
2. In winter (subzero) temperatures. I get from 40-50MPG in winters.
My average in ideal conditions (neither of the above) is around 57MPG, that's the EPA estimate so don't expect more than that unless you are into crazy hypermiling techniques.