Car Wash was sort of a time bomb. When it was released critics largely didn't get it, but the film's frenetic day-in-the-life energy and cast of rising stars (including early Bill Duke and Danny DeVito performances) makes Car Wash feel quite a bit eternal - as does the perennial popularity of the title track. It was an early effort by Joel Schumacher, who intended it to be a musical. Director Michael Schultz went on to direct some really wretched films like Sergeant Pepper's Lonely Hearts Club Band, but he also directed Krush Groove and The Last Dragon, touchstone pictures of the 80s.
I really like this trailer - it's got a nice bit of energy to it, and it doesn't spoil the whole thing. The trailer really works in that it's got me jonesing to watch Car Wash again, a movie I haven't seen in the better part of a decade.