Production began on location in Chicago in April 1983, then moved to Los Angeles for 45 days, and finally two weeks at a soap factory in Wilmington, California, with additional filming taking place at Universal Studios. Shooting wrapped on August 18, 1983. All 10 days of filming in Chicago were exteriors at night, on locations that included platforms of elevated subway lines and the depths of Lower Wacker Drive. For Hill, the subways and their look was crucial to the world of the film and represented one of three modes of transportation—the other two being cars and motorcycles.