NEW YORK - An outdoor advertising company says its use of mobile phone data to learn about potential consumers is based on anonymous information.

Clear Channel Outdoor Americas spokesman Jason King said in a statement Sunday its RADAR program used for billboard advertising has existed for years.

U.S. Senator Charles Schumer is calling on the Federal Trade Commission to investigate the technique. The New York Democrat wants to know if the company has employed deceptive trade practices because consumers may not know their location data is being monitored.

Company officials say they don't collect any identifiable information about consumers.

Clear Channel Outdoor operates more than 675,000 billboards throughout the world.

A FTC representative hasn't responded to a request for comment on Schumer's proposed probe.