The auto industry gathered in Detroit on Sunday, on the eve of the last winter edition of North America's premiere auto show, as carmakers grapple with a contracting market and uncertainty in the year ahead.Concerns over the health of the global economy and a US-China trade war loomed over the North American International Auto Show, as it prepared to open Monday with the first five days dedicated to the media and industry insiders. The show opens to the general public on January 19.While a number of major announcements were expected -- including an anticipated strategic alliance between Ford and Volkswagen -- there will be fewer automakers and new car unveilings, making it more subdued. "This is a transition year for the Detroit show," said analyst Michelle Krebs of Autotrader. "It's kind of emblematic of where the industry is. We're in a transition in the industry."After a 10-year boom, analysts expect North American auto sales to contract in 2019, as consumers face pressures and carmakers grapple with multiple uncertainties. Rising interest rates and car prices have squeezed car buyers, and fewer of them are able to afford increasingly pricey, technology-heavy cars. Kelley Blue Book predicted the average new-car price was up about three percent in 2018 to more than $36,000.- Tariffs cause uncertainty -Meanwhile, tariffs on imported steel and aluminum products and a potentially intensifying trade dispute between the Donald Trump administration and Beijing has automakers spooked, analysts said."Tariffs already had an impact in 2018," said Cox Automotive chief analyst Jonathan Smoke, adding that 47 percent of the vehicles sold in the US in 2018 were imported. "We believe about two percent of today's prices are because of the tariffs that were already implemented."The US is considering additional tariffs of 25 percent. Should it announce such a move by the February 17 deadline, it could have a substantial impact on the industry and stock markets, Smoke said. "We believe that they are likely to move forward with some form of that tariff, because it becomes then a lever for them to force... further negotiations."Should tariffs raise car prices further, analysts said it could substantially depress the new car market. Consumers would flock to relatively cheaper used cars, which are in ample supply. A growing number of lightly-used, tech-heavy vehicles leased during the sales boom of the last few years are being returned to dealerships.The auto dealers association, which organizes the show, also was contending with the uncertainty of the show's very relevance. Almost all German carmakers abandoned the show this year, as more and more important announcements are made at other gatherings. Next year, the Detroit show will move from January, when it has been held for some 40 years, to June.- Goodbye winter - Organizers hope the summer weather will allow for outdoor events that allow attendees to try out the new cars and technologies on display."It's run out of gas now," said Krebs. "June could be a rebirth for the show."Among the few notable unveilings this year will be from Ford, which is expected to display a redesigned Explorer SUV and a more powerful version of its iconic Mustang sports car under the name Shelby GT500. SUVs and trucks will once again be the highlight, a symptom of North American consumers' shift away from sedans and small cars. Trucks and SUVs made up a majority of new purchases in the US last year. "The SUVs have become cars with SUV bodies sitting on top of them," said Karl Brauer of Kelly Blue Book. Detroit's big three automakers have been ending production of almost all of their sedans and small cars, succumbing to the pressure of falling demand.To hedge against the threat of a global economic downturn, GM has announced plans to close underutilized US plants that made smaller, less profitable vehicles. Ford planned similar cost-cutting moves in Europe.