Some people are crazy generally!
I live near a very busy cycling area (hospital, university, major route into the city etc...), including a lead up to the busier bus route in Europe (apparently!). I see them all the time, no helmets or protective gear or reflectors, flowing skirts or scarves, MP3 players on, riding with no hands... Unsurprisingly it is renown for accidents, so many of them, I was with one guy who hit/was hit by a car a few months ago, called the ambulance etc... He was very lucky considering the impact (he flew!) and I couldn't see any helmet anywhere.
Even pedestrians though, I was on the same road yesterday going to the docs, stood waiting for a crossing to go green. A police 4x4 was screaming down the road, sirens and lights flashing and people were running across the road before it, including a man with young children, why can't people just wait???
Bad enough with normal traffic, suicidal with a train which can't just slam on the breaks to stop quickly or swerve like a car. Madness.