Harrison Ford would make one helluva New York City cop on traffic duty ... judging by the way he handled a tunnel backup in Manhattan.

Ford's Benz got trapped Sunday in between cars entering the Midtown tunnel. There was a pileup inside, and ol' Indiana Jones wasn't down to wait ... so he got outta his ride and started directing traffic!

No clear and present danger far as we can see, except maybe Harrison being late for a flight. You can hear other drivers' disbelief in the video because, quite frankly, it looked like he was shooting a movie the way he barked commands.

"Bridge & Tunnel Fugitive" ... or maybe, "Raider of the Midtown Tunnel." Ya get the idea.