The make and model of the flashy small sports car that Colonel Jack Knowles (Roy Scheider) drove was a black Porsche 356.
The title "The Fourth War" is derived from a famous quote from Albert Einstein which states: "I cannot predict how the Third World War shall be fought, or with what; I can, however, predict that the Fourth World War shall be waged with sticks and stones". Similarly, the film's closing epilogue states: "I cannot predict what breed of weapons will be employed in the waging of the Third World War; what I can predict is that the Fourth World War shall be fought with sticks and stones".
Though set in Eastern Europe on the border between Czechoslovakia and West Germany, the picture was actually shot in the province of Alberta in Canada which doubled for the Eastern block region of the environs of the German-Czechoslovak border.
The pistol Roy Schieder carries in the film is a 3.5" Colt Officers 1911 Model fitted with a stainless bilateral thumb safety. This would be a personally owned firearm as the US military never purchased anything but standard 5" 1911's and Officers models are somewhat uncommon.
German actor Jürgen Prochnow was cast as the Eastern European Soviet commander Colonel Valachev in this 1988-set cold war movie after having starred as the German U-boat commander Captain-Lieutenant Henrich Lehmann-Willenbrock in the successful Oscar nominated West German 1981 World War II movie Das Boot (1981) which had been made and first released about nine years earlier.