I-95 N to AC question

[Mobed]

I was always led to believe that the quickest way to AC from the I-95 N (from DC) would be to jump on route 40. During my latest visit (during the big snow storm) I opted to use the AC expressway. It felt much quicker then route 40. The thing is the roads were dead, so I had no traffic. I'm headed down tomorrow and wanted to get some others opinions on what is the best/quickest route.