Here is the Portland solution - Bike Boxes.
Portland's problem is "right hooks", based upon driving on the other side of the road.
While they talk about 'protecting cyclists from cars', the real impetus for this solution came as the result of two accidents where large trucks making right turns ran over bike riders.
Just a bit of a response to FF orig post: I not 70 yet, but I do remember L.A. in the late 40's and early 50's and riding the Big Red Cars, too.
Three points about those times:
1) People took the street car to go "downtown" (downtown L.A.) to shop and they dressed-up to do so - very different than today with malls everywhere and our VERY casual dress...and population density was rather low compared to today.
2) L.A. was a 2nd class city back then. Everything of meaning came out of NY or Chicago.
3) You never saw an adult riding a bike. (I did recently find a picture of my dad sitting on my mother's Schwinn single-speed. He had bought it for her to ride to the local grocery store (which I never saw her do), since like most families, we had only one car.
There's more I could add, but you likely get the idea - L.A. was a very different place back then.