The story is supposedly inspired by an incident Bradbury witnessed in Los Angeles in his teens. Bradbury's biographer Sam Weller, writing in The Bradbury Chronicles, describes it like this:
[...] in 1935 Ray was visiting Eddie Barrera at his house on Washington Boulevard when they heard a terrific crash outside. The boys bounded out the front door and saw a smoldering car about a hundred yards up the street, in front of a cemetery. The car had hit a telephone pole head-on and the passengers had been catapulted onto the pavement. [...] Three people had already died; another - a woman - was barely alive.
It was the sight of this woman that created a vivid memory that compelled Bradbury to think about the event over and over until, some eight years later, he was inspired to produce "The Crowd", which was first published in Weird Tales in May 1943. Today, you can find the story in The Stories of Ray Bradbury.
In The Complete Stories of Ray Bradbury: a Critical Edition, Jon Eller gives a little bit more information: that Bradbury was located at Washington Boulevard [Eller says Avenue, but there is no Washington Avenue in LA] and Berendo Street. Armed with this information, and Google Maps, this allows us to work out where the crash must have taken place: outside Rosedale Cemetary. The nearest part of the cemetery is about a hundred yards from the corner of Berendo and Washington.
View Larger Map
I thought I would try to locate detailed information about this car crash. Such an incident must surely have made the local press, I thought.
Searching through the online archives of the Los Angeles Times for 1935, I found just one news story that contained details of a car crash and a reference to Berendo/Washington, reported on 1 May 1935.
Unfortunately, none of the content ties in with Bradbury's recollection. The headline, "AUTOS TAKE TWO LIVES", gave me hope that this was indeed the account of the source of "The Crowd". But alas this one brief news story tells of two separate road traffic accidents happening the day before, both being incidents where pedestrians were hit by cars... and reports a conviction for manslaughter due to dangerous driving in another incident... and reports on a police officer being struck by a motorcycle and sidecar... and reports on a court appearance by a man arrested for drunk driving... and on and on.
I was forgetting. This is Los Angeles. The home of the road traffic accident, even in 1935.
No wonder Bradbury was always afraid to drive, and became a champion of public transport!