What was the point of the car chase?

Or his mettle.

Yes, it was definitely put in for audience excitement, and it worked on that level even compared to the ludicrous car chases they put in today's movies (I'm talking about you Bourne Identity). However, the Bullitt car chase was set up badly and seemingly without any thought to logical story progression. I mean, the bad guys were tailing Bullitt the whole time he took his cab ride with Robert Duval, and yet the moment he gets back to his Mustang and spots them, they high tail it outta there. Why were they following him in the first place? Within the story context I suppose it was in order to make sure he didn't learn that the Ross that had been killed was a decoy. But what was their ultimate motive? Were they going to kill Bullitt if he found out about the fake Ross? Wouldn't they have just killed him anyway? A couple mob hitmen that've just shot a witness and a cop wouldn't stop there. Why not kill Bullitt while he's cruising around in the cab? Because the filmmakers wanted that car chase. But it could have been set up better, even marginally so. Say the hitmen wait for Bullitt to get back to his Mustang then take a shot at him and miss and he shoots back and misses and then they're off and the chase is on. Even that would be dopey because really, they should have got him while he was in the cab. Anyway, the chase was pretty cool, even if the whole movie before that was kind of slow. But that was pacing back then. And the airport chase and shootout was superb. I can't help feeling that Michael Mann took some of that for his final scene in Heat (which was also superb).

"Yes, this was just for excitement."

- From a marketing standpoint, quite so, just as with switching the locale in the novel from New York to hip, counterculture San Francisco and altering the main character from a tired, on-the-verge-of-retirement detective to a younger one with a rebellious, maverick quality (and a beautiful girlfriend).

"It's no better than most other Hollywood police films which present the police perspective without criticism."

- There's actually some subtext offering criticism of Bullitt's single-minded pursuit of the hit men. When the supposed witness dies and Bullitt smuggles his body out of the hospital and covers up his demise, he emphatically tells the doctor, "If Chalmers finds out that Ross died, he'll fold this up and I want the man that killed him." This is the first signal that Bullitt is going to start bending rules and skirting procedure in order to nab the assassins before Chalmers can use his public platform to escape embarrassment by blaming police for the whole fiasco (as Chalmers has indeed explicitly warned him).

That subtext is eventually articulated by Cathy when she confronts Frank on the roadside with her observation that he's becoming desensitized to violence, and expresses her concerns over what the job is doing to him. Those concerns, and the thematic subtext they represent, play out after Bullitt has tracked the real Ross - who engineered the entire impersonation/assassination scheme - to the airport and spooks him into fleeing by boarding the plane as passengers are returning to the terminal, initiating another public-endangering pursuit and culminating in a shootout and two more deaths.

And it's this subtext that underlies the final scene, in which Bullitt gazes introspectively into his bathroom mirror while Cathy sleeps peacefully in the adjacent bedroom, and the film concludes on a symbol of violence: Frank's gun and holster.

The chase was also there because everyone in the audience knew it was Steve McQueen doing his own driving (and he probably WANTED to have the scene in the movie!) The audience knows that
Jackie Chan and Tom Cruise do their own stunts, and that knowledge puts more asses in theater seats. The worse Jackie Chan got hurt making a movie, the better the film’s BO. It’s human nature.

I regret that McQueen and Paul Newman never had a V8 showdown with each other on film. They were 2 sexy, handsome top-of-the-A-list MOVIE STARS and I bet every theater seat occupied by a lady would have been soaked.