The campaign used this iconic OOH placement and created a simple microsite that counted the number of cars that passed it and measured their carbon footprint in real time. It then converted the number to show how much carbon would have been saved if all of the cars were airport coaches instead.
As more and more people began to talk about the campaign, Sweedish Airport used the image across all integrated pieces - magazine, traditional OOH and print. Check out the short case video here to see the full overview:
What I love most about this idea is that it is so simple. 50 cars = 1 coach. Let's make a literal installation of that fact and use it to be the foundation of the entire campaign. They could have simply made this a one-off tactic to 'add-on' to the integrated work. But they didn't. And it became something much bigger.
I can't find the link to the microsite but if anyone does, please flip it my way. Great work to all those involved.