When I used to ride along with the State Police, one of them explained to me that if you saw a broken taillight on an older car there in Lane County, you pulled them over.

If they couldn't afford to fix the taillight, they were poor.  That meant they probably couldn't afford insurance either and likely had been suspended for DUII.  

When you stopped them, you had a major traffic infraction (DWS) and sometimes another DUII both of which the boss liked you to write up.  

If it was just a broken taillight, they either got a warning or a ticket, based primarily on their attitude.  

So if you see a guy driving a beater, particularly in Cottage Grove, Veneta, or River Road, go for 50/50 odds on that DWS.