Next month I will be going to visit my grandparents with my husband and son. We will be flying and won’t have our vehicle with us. We had planned on renting a car, but my grandparents keep saying we don’t need to. But I’m terrified of riding with them. My grandmother has been involved in several serious accidents in recent years. And the last few times I rode with my grandfather he almost drove into oncoming traffic more than once. Is there a polite way of explaining that we’d be more comfortable renting a car?