This is a worthwhile article from the Providence Journal published in 2007 that goes through some of the common objections to the deregulation of Massachusetts Auto Insurance.   For some politicians like Joan Menard, D-Somerset,  the primary issue that caused most concern is how competing auto insurance companies in Massachusetts would set rates and what data is at their disposal in making those rates.  This particularly articles gives a good early-stage view at how prevailing opinion has developed over time within Massachusetts car insurance circles.