What is the word for wanting something bad to happen to yourself?

Passive suicidal ideation

"...the wish to die during sleep, to be killed in an accident, or to develop terminal cancer..."

http://www.currentpsychiatry.com/the-publication/issue-single-view/passive-suicidal-ideation-still-a-high-risk-clinical-scenario/651a76321f5ec282d271b194343a9bfd.html

Agree with the comments above. Suicidal seems to fit the bill well (since a person wants to get in a car accident):

wanting to kill yourself

(Longman)

A softer word would be self-destructive:

deliberately doing things that are likely to seriously harm or kill yourself

(Longman)

masochistic

masochism: Psychoanalysis the directing toward oneself of any destructive tendencies Collins Discovery Encyclopedia

If you'd take a phrase instead of a word, I'd go with "glutton for punishment". Still, this means more like trying over and over to get something one wants DESPITE the fact that bad things keep happening in attempting the pursuit. So Elian is probably right: it's masochistic.

You may have found the word Lachesism in this buzzfeed article, which defines it as "the desire to be struck by disaster - to survive a plane crash, or to lose everything in a fire". As far as I can tell it is a word made up by this Tumblr blog.