About two-thirds of motor carriers surveyed plan to increase capacity in the next 12 months, up from 51% last quarter, a study from Transport Capital Partners said.

While heavy-duty truck makers said last week that they do not share Navistar International’s assessment that engine castings are in short supply, foundry executives said the recession eliminated industry capacity and problems could become more noticeable if demand for metal parts continues to rise.

Even as expectations for the nation’s economic growth remain subdued, trucking may be on the cusp of one of its most profitable rides ever as freight demand in 2012 pushes against the limits of industry capacity, according to industry experts.

ATLANTA — Shippers and brokers say they anticipate freight perils ahead in 2012, with a looming lack of truck capacity that could be exacerbated by a possible reduction in drivers’ allowable hours, according to comments during a recent industry event here.

PHILADELPHIA — The combination of rising truck equipment costs, the driver shortage and increased government regulation is forcing shippers to confront a new reality: Capacity is no longer “infinite,” and new ways to improve efficiency must be found, several industry experts said last week at the Council of Supply Chain Management Professionals annual conference.

PRINCETON, N.J. — There could be an “instantaneous capacity shortage” in the United States this year or next because of a “perfect storm” fed by an aging, shrinking truck fleet and a lack of good drivers, said Paul Will, president and chief operating officer of Celadon Group.

I believe there is no looming capacity shortage and there are plenty of truck drivers, even after we lose more than 200,000 drivers through CSA, as some experts predict.