Yeah, but don’t go overboard on this. Some hypermilers will accelerate super-slowly which causes problems behind them, or they’ll coast down long hills and end up grossly over the speed limit, or roll through stop signs so they don’t have to waste energy stopping and starting again, or one of my favorites, they’ll turn the car off on long downhill straights so they can move without using any fuel.
These techniques will increase your mpg, but they are also incredibly stupid from a safety standpoint and should not be done.