The companies that have the biggest budgets to test placements like this -- at high CPMs -- are brand advertisers (Gap, Coke, GM etc). Where this product fails for me is that I don't see a brand advertiser paying money to deliberately associate their brand with one of the most irritating friction points on the web.

Tho some do advertise at toll booths: http://www.e-470.com/images/plazawrap.jpg So maybe there's a fool willing to slap an ad anywhere it will stick.