if the freeway were packed with country music listeners, the billboards might make a pitch for casinos. If National Public Radio were on, the billboards could change to ads for a high-quality car or a gourmet grocery.
What's the point? The demographics of the individuals driving along the road from day to day is not going to change between one day and the next. I can see sureveying the demographics of those on the road through car stereos, but not updating the billboards live.
