Ask Marilyn

When I’m on the highway, another driver often will slowly catch up with me and pass, then move in front of me and slow down. I have to disengage my cruise control. Why do people do this? Do they just want to be in front?

—Gwin Tate, Miami, Fla. I believe there’s a good reason. As the other driver slowly catches up, he sees he can decrease his speed just slightly and stay behind you forever, or he can speed up and pass, then continue on his somewhat faster way. But this passing maneuver requires major acceleration, and when he moves back in front, he overcompensates when he eases up on the gas, thus slowing down too much. It’s annoying, but understandable.