• 02.01.05

At 1600 Pennsylvania Avenue, of Course, It’s ” Rush Limbaugh”

What: Block-by-Block Radio Monitoring; Available: Now.

Care to know how many people in Fairfax, Virginia, were listening to Howard Stern last Wednesday? At 9:12 a.m.? At the intersection of Routes 50 and 123? Okay, neither do we, really. But radio stations and advertisers do — and new technology is delivering the answer. Since last June, Herndon, Virginia-based Mobiltrak has logged the listening habits of 1 million commuters a month by monitoring electric radiation. Chances are, if you’ve driven through the Washington, DC, area recently, you’ve unknowingly participated in Mobiltrak’s survey.


Mobiltrak promises data that’s a lot more specific than the weighted samples used for decades by Arbitron to estimate audience size and demographics. As cars pass its towers at busy intersections, sensors “sniff” electrical radiation emitted by each car stereo. Because radios emit a unique level of radiation to translate each frequency, the Mobiltrak nose is able to distinguish what station is playing. In other words, Howard Stern on WJFK has his own special smell. (Uh, like we didn’t already know.) Once a signal is picked up, it’s routed to Mobiltrak’s servers in Phoenix. Subscribers can then access all the data via the Web.

Within 90 days of entering the Washington market, Mobiltrak had signed up all the city’s major stations for subscriptions averaging $2,500 a month. Advertisers (including Home Depot, which has piloted the system) pay $750 a month per location. And in California, a company called Smart Sign Media is even using the technology to customize its video-billboard advertising in real time. Smart Sign sensors measure the listening habits of passing traffic, then prompt massive LED screens to display demographically targeted advertisements. What it can’t do (yet): personalized pop-up ads for every car radio on the freeway. “Just think about the logistics,” says Mobiltrak partner David Boice. “A new ad every second? The margin of error would be tremendous.”