New York, Los Angeles, Chicago, San Francisco today join Philadelphia and Houston as PPM markets in the top ten radio metros; Nassau-Suffolk, Middlesex-Somerset-Union, Riverside-San Bernardino and San Jose also go electronic.Arbitron Inc. (NYSE: ARB) announced today that it has commercialized its Portable People MeterTM radio ratings services in eight new markets. Arbitron has released radio audience estimates for the September 2008 PPMTM survey month (August 21-September 17) to its subscribers in New York, Los Angeles, Chicago, San Francisco, Nassau-Suffolk, Middlesex-Somerset-Union, Riverside-San Bernardino and San Jose.Effective today, the PPM radio audience estimates for these markets should be used as the basis for buy/sell transactions of radio commercial time among subscribing stations, agencies and advertisers. In addition, the July and August PPM survey months, which Arbitron had previously released as “pre-currency” information, are now designated as “currency” data. The Spring 2008 diary-based radio audience report (April 3-June 25) is no longer deemed “currency” for buy/sell transactions.Said Steve Morris, chairman, president, chief executive officer, Arbitron Inc: “We are commercializing our Portable People Meter radio ratings services in these markets in order to meet our obligations to our customers and to the radio industry.””Without PPM, the industry will not have up-to-date estimates of the radio audience in the nation’s largest markets to facilitate an efficient buy-sell process for radio advertising. Advertisers are in the process of planning their ad budgets for all media including radio. Our goal with the commercialization of the PPM is to help radio remain competitive in an increasingly challenging media marketplace,” said Mr. Morris.