Diesel passenger vehicles are largely nonexistent in the United States today, due in large part to a legacy of the 1970s and 1980s when light-duty diesels were plagued by poor performance, unreliability, noxious exhaust, and high noise levels. In recent years, however, manufacturers have addressed many of these shortcomings, and diesels can offer fuel economy and performance advantages over gasoline vehicles. Nonetheless, barriers to diesel passenger vehicles remain. This report investigates the prospects for re-growth of diesel's share in the U.S. light-duty market. Topics addressed include rationale for diesel use, emissions challenges, cost and consumer perception implications, and a comparison of the European and American markets.