As I read it, it's not paint, it's actually mixed into the concrete.
As far as whether it is effective or not... well, it's probably more effective than not doing anything (additional costs and construction techniques need to be considered). Overall, I think absorbing pollution near the vehicles that produce it is a good idea. The raw amount of paved area in the world makes it an attractive target for any 'green' development (I've heard of projects trying to put solar panels into roads).
As far as whether it is effective or not... well, it's probably more effective than not doing anything
That doesn't make sense. Resources are finite. If something is not effective, then you shouldn't be wasting time and money on it, definitely not public money.
The raw amount of paved area in the world...
Have you thought of the raw amount of air in the atmosphere?
... makes it an attractive target for any 'green' development
You hit on a good problem here. "Solutions" like this one end up being nothing but certificates for companies and governments to show that they are doing "sustainable green development (TM)".
As far as whether it is effective or not... well, it's probably more effective than not doing anything (additional costs and construction techniques need to be considered). Overall, I think absorbing pollution near the vehicles that produce it is a good idea. The raw amount of paved area in the world makes it an attractive target for any 'green' development (I've heard of projects trying to put solar panels into roads).