Bad credit shouldn't affect car insurance, experts say. States are listening.

Pedro Montenegro has an immaculate driving record.

But even though Montenegro said he has never been in a car accident, nor been issued a ticket for a moving violation, he has never in his adult life qualified for affordable car insurance. That's something that Montenegro, 30, who earns a "good living" as a public relations staffer in Washington, D.C., says is inextricably tied to his poor credit score, which is in the low 500s.

He most recently received multiple monthly premium quotes of around $350 for minimal coverage for one...