Huge rear-drive sedans used to dominate America's highways. Today, this once-plentiful species has dwindled to just a few domestic nameplates: the Ford Crown Victoria and Mercury Grand Marquis, and two offerings from General Motors: the Chevrolet Caprice and the Buick Roadmaster.As a class, they've moved from commonplace to niche, selling steadily but moderately to people who still appreciate their roominess and view their dimensions as a safety plus. Conservatively styled, their objective is to provide comfort, convenience and value in a big package built for highway cruising. Click here to read more