It may seem mundane: having a relative drive you around to do errands.
But to the tennis champion Serena Williams, a decision to let her 18-year-old nephew drive her to meetings so that she could safely use her phone in the car filled her with misgivings that go to the heart of the national discourse on race and policing.
In a social media post on Tuesday, Ms. Williams described how spotting a police officer on the side of the road during her ride with a black youth at the wheel inspired thoughts of life and death.