I was researching the evolution of vehicular traffic in New York City and stumbled across a series of letters to the editor written about “Explosion Whistles”. Apparently in the mid 1920’s Ford vehicles were equipped with ear splitting whistles that were powered by exhaust, and were the “loudest and shrillest warning signal in use”.
As this 1924 letter to the Editor of the New York Times states
“May I ask your attention and active co-operation in an effort to do away with the terrible nuisance of the so called “explosion whistle” now used by a great number of automobile trucks in the city? The reckless driving of automobile trucks throughout New York is a matter which has caused great concern to citizens, and has resulted in tremendous loss of life in recent years, and I believe that the use of these loud explosion whistles is a contributing factor to this danger, since trucks depend upon the affect of their loud whistles to frighten pedestrians and other vehicles out of the way”.
So how loud were these whistles? One Model T restorer said he removed the explosion whistle from his 1923 Ford vehicle because “I was uneasy about waking the dead. However, for cars having questionable brakes, it also seemed a probable advantage to lift folks out of their shoes a block away. “
You can hear a more muffled sound of a 1920’s explosion whistle in the video below. Emily Thompson a Princeton University history professor has produced a sound map of New York City in the 1920’s and 1930’s. By matching municipal noise complaints from that era to old newsreel footage, she was able to create a New York City soundmap block by block.