Auto shows are not passé, despite decisions by several auto makers to skip January’s North American International Auto Show in Detroit.

But they are “not as relevant as they used to be,” says Michael Bernacchi, University of Detroit-Mercy marketing professor.

These assessments come in the wake of Nissan Motor Co. Ltd.’s decision to pull out of the Detroit show. The move comes hard on the heels of similar decisions that will free up floor space where brands such as Rolls-Royce, Suzuki, Mitsubishi, Land Rover and Ferrari once had displays.

Nissan also is pulling out the Chicago Auto Show. Porsche Cars North America Inc. skipped Detroit last year and will do so again this year.

“It’s a sign of the difficult economy that we find ourselves in,” says Alexander Edwards, president of California-based consultancy, Strategic Vision Inc.

In a market where the seasonally adjusted annual rate recently hit a 25-year low, “it’s a time to be a little more conservative” with marketing budgets, Edwards says.

Nissan spokesman Fred Standish confirms the auto maker’s decision was prompted by economics, nothing else.

“These are rough times,” he says. “The dealers understand.”

Fresh off a trio of new-vehicle introductions at last week’s Los Angeles auto show, Nissan has nothing else in its pipeline to coincide with Detroit and Chicago, Standish says.

But Nissan had earmarked Detroit to debut a concept version of a light-commercial vehicle the auto maker plans to build at its plant in Canton, MS. Those plans changed after Nissan reviewed its marketing budget.

Bernacchi draws a parallel between Nissan’s decision and this week’s move by General Motors Corp. to end its 9-year, multimillion-dollar endorsement deal with golf superstar Tiger Woods. In difficult economic times, Bernacchi says, “we quickly find what we can do with and do without.”

Standish notes many consumers today use the Internet when shopping for new vehicles.

Bernacchi concurs, but says auto shows are superior to websites for getting up close and personal with new vehicles.

“You can’t kick the tires on the Internet,” he says.