Independent filmmaker Rob Nilsson’s gritty drama is dedicated to John Cassavetes, who pioneered the extensive use of improvisation in his movies. Signal 7 centers around a day in the life of two middle-aged San Francisco cab drivers, Marty (Dan Leegant) and his buddy Speed (Bill Ackridge), both who are living in a state of turmoil, unable to shake the anger, loneliness and anguish of their lives.