At the end of Back to the Future, Doc, Marty, and Jennifer are readying to take a trip to 2015. Marty expresses his concern that Doc isn't giving himself enough road to get up to 88 miles per hour (the usual speed required for time travel—but if you've ever taken a physics course, you already knew that). Doc responds with "Roads? Where we're going, we don't need roads." And then the DeLorean flies off and the audience cheers. It's awesome.