The Taxi Driver story was partially autobiographical for Paul Schrader, who suffered a nervous breakdown while living in Los Angeles. He was fired from the AFI, basically friendless, in the midst of a divorce and was rejected by a girlfriend. Squatting in his ex-girlfriend's apartment while she was away for a couple of months, Schrader literally didn't talk to anyone for many weeks, went to porno theaters and developed an obsession with guns. Schrader was working at the time as delivery man for a chain of chicken restaurants. Spending long days alone in his car, he felt--I might as well be a taxi driver. He also shared with Travis Bickle the sense of isolation from being a mid-Westerner in an urban center. Schrader decided to switch the action to New York City only because taxi drivers are far more common there. Schrader's script clicked with both Martin Scorsese and Robert De Niro when they read it.
I gotta get in shape.
Too much sitting has ruined my body.
Too much abuse has gone on for too long.
From now on there will be 50 pushups each morning, 50 pullups. There will be no more pills, no more bad food, no more destroyers of my body. From now on will be total organization. Every muscle must be tight.
Deep brass and woodwinds are also evident. Barnett heard in the drumbeat a wild-eyed martial air charting the pressure on Bickle, who is increasingly oppressed by the corruption around him, and that the harp, drum, and saxophone play significant roles in the music.
All the animals come out at night - whores, skunk pussies, buggers, queens, fairies, dopers, junkies, sick, venal. Someday a real rain will come and wash all this scum off the streets. I go all over. I take people to the Bronx, Brooklyn, I take 'em to Harlem. I don't care. Don't make no difference to me. It does to some. Some won't even take spooks. Don't make no difference to me.
Robert Barnett of MusicWeb International has said that the Soundtrack by Bernard Herrmann contrasts deep, sleazy noises, representing the "scum" that Travis sees all over the city, with the saxophone, a musical counterpart to Travis, creating a mellifluously disenchanted troubadour.
Barnett also observes that the opposing noises in the soundtrack—gritty little harp figures, hard as shards of steel, as well as a jazz drum kit placing the drama in the city—are indicative of loneliness in the midst of mobs of people.
Taxi Driver by Martin Scorsese
The music by Bernard Herrmann was his final score before his death on December 24, 1975, and the film is dedicated to his memory.
The scene in which Travis is talking to himself was completely created by Robert De Niro(listen to the speech); the screenplay simply says: "Travis looks in the mirror". De Niro repeats himself, because Martin Scorsese was listening to the takes on his headphones, and with the background noise, Scorsese did not know if De Niro could be heard clearly. The line itself derives from the classic 1953 western Shane.