Americans trying to reduce spending in a weak economy are using public transportation in high numbers not seen since the 1980s, the American Public Transportation Association (APTA) said Monday. The number of passengers on the country's public buses and trains between July and October jumped 6.5 percent over the same period last year, with about 2.8 billion trips, marking the biggest increase in 25 years, APTA said. “The record increase in public-transportation trips demonstrates the exceptional value of public transportation in today's economy,” said APTA president William Millar. Americans' use of public transportation already had been rising because of recent high fuel prices that made driving expensive, and the dramatic downturn in the economy has kept the trend continuing even as energy prices have retreated sharply. “The fact that public-transit ridership surged while gas[oline] prices and highway travel declined shows a growing demand for more bus and rail services,” Millar said. The increase in use of public transportation came as Americans traveled 4.6 percent fewer kilometers on U.S. highways, APTA said.