[NowThenGoodBad]

*per potential impressions per dollar

You can actually use that as a negotiating point. Let's say a new route is opened causing traffic to bypass a normally high traffic point. The advertiser might still price per potential impression per dollar when the reality is significantly different.

Not to nitpick but it's important for people to do their homework on this and realize that those selling the ad space are going to price on the higher end of potential impressions.