From the Associated Press — Michigan drivers who renew or buy car insurance face a choice starting this week: stick with unlimited medical coverage, go with less or — for seniors with Medicare — opt out entirely. The decision is a signature feature of a new law that will lower the cost of personal injury protection benefits. It boils down to people’s risk tolerance and desire for savings. But unlike with choosing a deductible, the selection can have long-term implications in the event of a serious crash. Insurance agents say many people whose policies are up for renewal are staying with unlimited medical for now.