P.M. BRIEFING : Volvo’s Agency Quits Over Ad

NEW YORK — The car maker Volvo’s advertising agency quit today, saying it was taking responsibility for the bogus commercial depicting a Volvo that resisted the stomping of a big pickup truck while other cars collapsed.

Scali McCabe Sloves Inc. said it was resigning as the ad agency for Volvo Cars of North America because of questions raised about the production of the so-called Monster Truck commercial for the Swedish car.

The ad showed a Volvo as the only car left standing after a pickup truck with oversized tires ran over a row of cars. It was later discovered that the Volvo had been reinforced and the other cars weakened before the ad was shot.

The ad agency’s chairman, Marvin Sloves, said in announcing that the agency was resigning the account that agency executives had worked for 23 years to establish Volvo as “one of the most respected and admired brand names in North America.”