A California Good Driver, as defined by Cal. Ins. Code § 1861.025, must be charged a rate that is at least what percentage below the insurer's otherwise-available rate for the same coverages?

Why this is the answer

Cal. Ins. Code § 1861.025 requires that the rate charged to a qualifying Good Driver Discount Policy applicant be at least 20% below the rate the insurer would otherwise charge the same applicant with the same coverages, vehicle, and territory if the Good Driver status did not exist. The discount is mandatory — an insurer cannot opt out of offering it or use a smaller percentage. CDI audits class plans annually to verify that the differential is preserved across every cell of the rating algorithm.