What’s the rule? A car length for every 10 mph? I don’t always follow that rule, but my friend drives way closer to the car ahead than I like. We’re in freeway traffic that is crowded but moving. Several times the brakes are necessary when our lane unexpectedly slows. I sense myself applying brakes of my own, griping my calf and digging my heel into the floorboard. I’m gripping a phantom steering wheel as well–my traps (upper shoulder muscles) clenched in an effort to gain control. My tongue presses back into my throat in a half-swallow. My mother was a nervous passenger, too…