A sequel titled "Still Running" was planned and different scripts were written. But Billy Crystal and Gregory Hines did not think any of them were strong enough to warrant a sequel and turned them all down.
The suspension systems of three Chevy Impalas were destroyed filming the "El" train tracks chase scene.
In several outdoor scenes, snow is simulated with foam.
Tom Selleck and John Travolta were also offered the roles of Hughes and Costanzo. Selleck turned it down due to commitments to Magnum (1980) while Travolta's agent at that time, Michael Ovitz, felt that the project was wrong for him.
On the television series "The Directors," Peter Hyams stated that when MGM offered him the project following the success of 2010 - L'année du premier contact (L'odyssée continue) (1984), the script focused on two old New York City cops who want to retire. Hyams suggested his idea of two young Chicago cops who don't retire and MGM agreed. The script was originally written with Gene Hackman and Paul Newman in mind for the lead roles.