Since the Greater Los Angeles Auto Show made its debut in 1907, selling cars has been strictly prohibited.

But that doesn’t mean cars aren’t really being sold.

As local dealers descend on the Los Angeles Convention Center this week, many were expecting the event to provide a welcome sales boost.

Tony Marino, sales manager for Shammas Automotive Group’s downtown Volkswagen, Porsche and Audi dealerships, said the show has a big impact on business, with sales rising anywhere from 3 percent to 10 percent in the days and weeks after it closes.

Shammas’ Downtown L.A. Mercedes-Benz can count on 10 vehicle sales in each of the first three months of the year as a result of exposure, said General Sales Manager Martyn Mayhead.

State law prohibits negotiating the price of a car at an auto show, and dealers buy their franchises from manufacturers for specific locations, said Andy Fuzesi, the show’s general manager, who also noted that the event was not the best atmosphere for a sale.

Many dealers welcome the opportunity to gather leads in a low-pressure environment, but not all car companies, which lease the exhibition space, handle the staffing of the show in the same way.

Some automakers craft schedules that allow multiple dealers to send salespeople, dispersing them over the 10-day public run. That allows them to chat up potential buyers, collect contact information and in some cases, schedule follow-up appointments. Other manufacturers choose to send only corporate employees, who gather contact information and funnel leads to the dealer with the ZIP code closest to the potential customer.

Shammas’ Volkswagen, Audi and Porsche dealership is sending six sales people. Saturn of Alhambra will also send six employees and Ehlers Cadillac in Los Angeles will send five people. The dealerships said they have no trouble getting on the schedule.

For dealers sending staff, the opportunity for a face-to-face meeting with potential customers can be invaluable, and many said customers won’t necessarily choose to visit the closest dealership.

“In this day of technology and computers and every other way of trying to attract business, it comes down to a one-on-one basis,” said Marino. “We’ve found people will go many, many miles if they make a connection with a salesperson. We don’t think that will ever change.”

Not every dealer has the opportunity to staff the show: General Motors Corp.’s Lincoln-Mercury brand and DaimlerChrysler’s Mercedes-Benz only send corporate employees.

“Since the manufacturers are supplying the representatives, you would hope they are better versed in highlighting certain points that customers, under a convention atmosphere, would be interested in seeing,” said Kirk Varga, general manager of Don Kott Lincoln-Mercury in Carson. “You don’t have time to do a complete product presentation; it’s more of a marketing presentation or overview. They’re more polished marketing professionals.”

The size and importance of the L.A. show is the reason Mercedes-Benz corporate does all the talking, said Mayhead, adding that his dealership staffs other shows, such as the California International Auto Show in Anaheim. In some cases, dealers at the L.A. show are also seeing the cars for the first time, which would make touting them more difficult.

Started in 1907 by Packard dealer Earle C. Anthony to provide Southern Californians with the opportunity to see new cars and trucks in a non-selling environment, the event was originally held in a large tent. It later moved to the glittery Pan Pacific Theatre and then to the L.A. Convention Center when it opened in 1971.

This year, more than two-dozen vehicles will make their North American and worldwide debuts at the L.A. show, compared to six last year.

The largest event to take place at the L.A. Convention Center, this year’s show is expected to draw more than 1 million attendees, about the same as last year.

While sales may increase in the time period following the show, and customers reference the show months later when some new cars they’ve previewed finally become available, it’s unclear how many of those sales were likely to have taken place.

“Does it really foster this influx of sales?” asked Todd Turner, president of consulting firm Car Concepts in Thousand Oaks. “I don’t think so. I think people who go to the auto show go because they are already predisposed to buy a car.”