This happened to my buddy. He got in a car accident or something. This was shortly after he graduated from high school, and his father had just died. He ended up on pain meds, ended up getting addicted after a couple of months. When his prescription ran out, he called up our mutual friend who was in to drugs and got more. This went on for about 18 months before he decided he wanted to become a veterinarian, somehow his friends and family weaned him off pills, and after two years was accepted in to vet school. Through no small miracle he made it through grad school and graduated, he's now pretty successful.
I grew up in a pretty rich suburb, we had time to help him and his family through the addiction, and he had a strong goal to strive for. Many people don't have the opportunities or strong safety net that he did.
I was crossing the street in mountain view on... monday I want to say... The driver had to take over manual control doing a right turn on to central expressway from castro st/moffett blvd. The car decided that it was time to pull on to the highway. There was a car in front of it waiting to turn right as well. It's kind of a weird intersection though, as there's a double set of train tracks right next to central expressway, which you cross, then come to a stop again, then turn right at a light. Add to the fact that it's a major public transit junction with the caltrain + VTA light rail stations (Two different train stations) at the same intersection means there's a lot of pedestrians to look out for. There's probably 10 such intersections in the country.
When all else fails, read the instructions.