Misuse of Death Penalty

The New York Times reports that the prosecutor in Glendale, CA has charged Juan Manuel Alvarez, the man responsible for yesterday's train crash that killed 11 people, with murder with "special circumstances". This makes Alvarez eligible for the death penalty. Recall that Alvarez tried to kill himself by parking his car on the train tracks, then changed his mind at the last minute and fled by foot, leaving his car parked. Ironic, isn't it?

In this case, the death penalty achieves nothing. In my opinion, the primary role of punishment is to act as a deterrent. Secondary roles are protecting society from criminals and reforming the wayward. The death penalty may achieve the first two goals in some cases. Retribution, however, is not a goal of the criminal justice system. What would be achieved by taking Mr. Alavarez's life?