Now the fourth-biggest maker of pickups in North America, Toyota won’t expand plants being built in Mexico and Texas until it’s confident that demand warrants added production, company president Fujio Cho said, according to Bloomberg News.

Toyota this year begins making Tacoma small pickups in Baja California, Mexico, its fifth North American vehicle assembly plant, and in 2006 opens a sixth in San Antonio to make the larger Tundra.

According to Bloomberg News, industry forecasters have said Toyota will likely lift production at the Mexican plant beyond the current annual goal of 30,000 trucks, while a Texas state agency in 2003 estimated the company probably will double San Antonio’s capacity to 300,000 trucks from an initial 150,000.

“I can’t say we’ve already decided” on expansion, Cho reportedly said. “Tundra isn’t such a great seller at the moment because it has such formidable competitors.”

Bloomberg News said the Tundra accounted for 4.4% of the 2.28 million large pickups sold in 2003, a segment that expanded 5.3%. Tundra sales lagged models made by General Motors, Ford and DaimlerChrysler’s Dodge, and were less than an eighth of the 845,586 F-Series trucks sold by Ford.

However, the report said, sales of the Tacoma, the second-best-selling small pickup in the United States after Ford’s Ranger, were 154,154 in 2003, or 21% of the 731,299 small pickups bought, according to Autodata Corp. Sales for the segment fell 8.2% last year.

“The Big Three are so strong in the truck segment, so it’s not easy for us to expand our sales,” Cho reportedly said. “If our products sell well, we can expand (San Antonio), but you never know unless you start selling them.”

Bloomberg News noted that Toyota made 1.28 million vehicles in North America, the largest car market, in 2003 and wants to be able to build 1.66 million in the region by late 2006. Its goal is 15% of global vehicle sales within a decade, up from about 10% now, and winning a bigger slice of US truck sales is key to that goal.

“With Tacoma, they’ve got a big share of a declining segment, compact pickups, so I’d expect them to be cautious about ramping up too quickly until they know who’s buying these things,” George Magliano, director of auto research for Lexington, Massachusetts-based forecaster Global Insight, told Bloomberg News.