There are approximately 15 optional factors for determining auto rates under Proposition 103, including such factors as marital status, and current law says only that the average weight given to these factors cannot exceed that given to any of the three mandatory factors.

Insurance industry groups representing both companies and agents have opposed the proposed regulations, claiming that decreasing the importance of location would effectively force consumers who live in rural areas to subsidize coverage for those who live in more densely populated urban areas.

“Common sense tells us that an increased exposure to a particular risk equates to a greater likelihood of being adversely impacted by that particular risk,” said Mr. Rataj.

He added that, “Actuarial studies have shown that automobile accidents and thefts occur more frequently and with greater severity in urban areas, so it is only fair and logical for those consumers to pay premiums reflecting this higher potential for loss.”

He said Mr. Garamendi's proposed regulation would hinder insurers in their ability to provide consumers “with accurate and equitable rates.”

The California Department of Insurance has scheduled a Thursday workshop to discuss the new regulations in addition to a formal hearing in late February.

Ballot initiatives that would allow for greater weight to be given to location have also been filed with the state attorney general. A consumer group, the Foundation for Taxpayer and Consumer Rights, said it had found draft versions of the initiatives on the Web site of the Association of California Insurance Companies.

The ACIC, which is the Western affiliate of the Property Casualty Insurers Association of America, denied being the source of the initiatives. ACIC president Sam Sorich said the group had only been asked to review the drafts by Mercury Insurance and had not yet made a decision whether or not to support them.