blackout

To a degree unprecedented in history, combat in World War II was directed against civilian populations, and this was especially the case with air raids, such as the Blitz. Advances in avionics (aircraft instrumentation), radar, and radio-guided direction finding made nighttime air raids not only feasible but common. Brightly lit cities made excellent targets. Even in rural areas, lights were readily spotted from the air. To reduce vulnerability, cities in the war zones instituted strict blackout policies, which restricted or eliminated the use of street lighting and required citizens to provide opaque blackout curtains and shades for all their windows. Automobile headlamps were fitted with slitted covers to reduce light emission to an absolute minimum. Even in the United States, which had escaped air raids, blackout curtains and shades were installed in public buildings. In some locations— for example, New York's famed Grand Central Station— windows were permanently blacked out with paint. Periodically, throughout American cities, air raid drills were conducted, largely to familiarize Americans with rapid blackout procedures. Blackout policies were introduced not only to help defend against nighttime air raids, but, in coastal locations, to combat the menace of attack from the sea. German submarines lying off the East Coast of the United States often targeted merchant ships that were silhouetted against the bright lights of coastal cities. In the United States as well as in the cities of Europe and Asia, blackout regulations were enforced by air raid wardens and other officials. Sanctions for violations of blackout policies, orders, and ordinances ranged from a stern lecture to fines to incarceration.