What's The Problem With this State Trooper

One night in 1990 I was driving up Burlingham Road, New York.  A State Trooper stopped me for a burned out tail light.  He asked me for my registration.  I handed him a registration that was 2 years out of date and for another car.  The trooper looked at it and said, okay you check out okay.  He said just get that tail light fixed.  I laughed all the way home.  What kind of dope was this trooper?  Is he blind?  Can't he read?  See I was checking him out for what kind of dope he was.  This is the truth too.