The victim is dead, gone. Forget about the victim, their life is over. Let's not ruin the life of the drunk driver or teenager, also. Often we're glad that we're not the ones who have to decide. Christine McBride, a student currently at Princeton, took the dilemma of justice vs. mercy and brought it to the ultimate judge, God, to see how He weighs in on this issue.
Righteousness demands that a price be paid when the law is broken.
Righteousness is unyielding, while mercy allows for human failings and shortcomings. We just don't seem to allow for the convergence of love with judgment. I've often heard the argument that New Testament Scriptures present a merciful and loving Savior incompatible with the God of strict judgment depicted in Old Testament Scriptures. God found a way. He acted with righteous mercy.