Minnesota has the "whiskey Plates" for habitual offenders.  They have a special lettering system and people can spot the plate.  The person driving can be stopped by police at random to give breath tests and people can call the plates in if needed.  Not a fantastic solution, however they realized that people will continue to drive with revoked license and want the public to know.  Many times a drunk on the road will be driving (weaving) and by the time it gets called in, nothing comes of it.  I would like to at least know who they are, the DUI crowd when I am driving about town and I am sure others would like this insight.  It seems alcohol contributed to this horrible accident.  God bless all the families involved.