 The storm drain car chase scene was shot in a large air duct tunnel  below the four main bores of the Fort McHenry Road Tunnel in  Baltimore, MD. Fort McHenry permits Interstate 95 to pass under  Baltimores harbor. The air duct is only accessible from the  Tunnels Admin Building by stairs and a small elevator, so the cars  in the scene were chopped into several sections, taken three levels  below, reassembled and painted. Once filming was complete they were  disassembled once again and removed from the duct. The water was  hosed in from a nearby sprinkler main.