DETROIT — U.S. auto sales limped in at only about 852,000 vehicles in October, making it the worst single month of vehicle sales since 1992 — and, on a per capita basis, America's most abysmal level of auto sales since the 1950s. So at least two automakers launched new incentive programs, in an effort to jump-start the usual winter-holiday selling season.OEM executives on Monday could barely heap enough negative superlatives on a month that saw overall sales plunge by 32 percent compared with a year earlier. They moaned about an industry that basically has been losing sales and momentum since hurricane Katrina about three years ago, according to Mark LaNeve, North American vice president of sales for General Motors.The annual pace of sales in October was a horrific 10.5 million to 10.6 million units on a seasonally adjusted basis — more than two million units below the 12.8-million rate in a rotten September. October's sales pace marked the worst monthly rate since February 1983.GM's performance relative to a year ago was the worst among the Big Six automakers, with sales down about 45 percent. Chrysler's sales fell by 35 percent, Nissan's by 33 percent, Ford's by 29 percent, Honda's by 25 percent and Toyota's by 23 percent.The executives described nearly vacant dealer showrooms bled by battered consumer confidence, by more expensive and more-difficult-to-obtain loans, by financial market jitters that have sapped household wealth and by widespread Election Day anxieties. Even discussion of a GM-Chrysler merger in the background unsettled some consumers, they said.'This may have been a month that showed how low the industry can go,' said Jim Press, Chrysler's vice chairman. But, he noted, 'At some point, you have to hit the bottom of the bathtub, and in October we may have been there.'In an attempt to increase showroom traffic and sales from October's dismal levels, even modestly, Chrysler launched a new incentive program that it calls Rev Up America. And GM launched its seasonal Red Tag Sale a few weeks early.Inside Line says: If you're flush enough or brave enough or needy enough to buy a new vehicle right now, the world — or, at least, the showroom — is your oyster. — Dale Buss, Correspondent