Sort of. You can actually boost your speed a little by pedaling like mad down hill. Pros doing road races coast down the hills because there is so little benefit speedwise from pedaling down hill, they are conserving energy for the uphill portions. The guy who figures out to coast uphill will be famous.

One hill I frequent I can take coasting at 38. Peddling like mad I can almost hit 40. Not really worth it since there is another uphill right after it bottoms out.