Like the ocean’s tidal surges and retreats, the rest stop suddenly fills with people who swell the lines at the Starbucks and Burger King and occupy the dining area. Their murmur, with an occasional loud laugh, rises to the high ceilings where bare rafters evoke a ski lodge. Then the crowds dissipate, leaving the place nearly empty for a while but for the workers for HMSHosts, a concession company that operates the restaurants and market there and in about 80 other rest stops in 10 states. One man wiped tables over and over as they became vacated.