U.S. advertising expenditures fell 14% to $30.18 billion in the first three months of this year compared with the same period of 2008, according to data from TNS Media Intelligence.

“The ad market declined significantly in the first quarter, overtaken by a collapsing economy which prompted consumers and marketers alike to shut their wallets and conserve,” said Jon Swallen, senior vice-president of research at TNS, in a statement.

Second-quarter spending is on a “comparable plane to recent months,” he added.

Local media has been hit hard by cuts in spending from automotive, retail and local services advertisers, according to the report. Spot TV fell 27.5% year-on-year in the first quarter, with local newspapers and local radio down 25.1% and 26.8% respectively.

For national media, combined ad spending fell 8.5% versus last year. National newspapers (-28.5%), B2B magazines (-25.5%), consumer magazines (-19.2%) and other print media revenue declines were driven by fewer ad pages.

The Internet was the only medium to see growth. Online display advertising, which only includes banners, was up 8.2%, thanks to travel and retail spending, said TNS.

As expected, automotive companies—still the largest advertiser category—made substantial advertising cutbacks: down 28.4% to $2.3 billion, with dealers almost halving their spending.

General Motors spent $424.2 million on advertising in the quarter, a 19.1% decrease over last year, but still “a smaller rate of decrease than most of its competitors,” said TNS.

The top 10 advertisers in the first quarter of 2009 spent a combined total of $4.02 billion, a 5.7% decline from last year.

Procter & Gamble, the U.S.’s largest advertiser, slashed its spending by 17.8% to $674.1 million. The company trimmed TV allocations by nearly 30% across its brand portfolio while leaving magazine budgets untouched.

In contrast, Johnson & Johnson, the only other packaged goods marketer in the top 10, increased its spending by 28.9% over last year, its highest level of quarterly spend in two years.

Among the wireless telecommunication providers, Sprint Nextel increased its spending by 30.3%, to $317.7 million, primarily to promote a new bundled value plan.

Verizon Communications raised expenditures by 3.1% to $577.1 million, while AT&T registered a small decline of 1.2%, to $459.4 million.

Media companies responded to falling advertising by curbing their own spending. Time Warner cut 24.4% of its advertising budget, while News Corp. spent 15.7% less.