Good idea for reducing run-off, but will the water wash away the foundation of the road? Here in Hong Kong the concrete pavements are being replaced by bricks on a layer of sand, and the typhoon rains wash away the sand, causing the bricks to drop and the pavements to become uneven. Not good for a pavement, but a hazard for a road.

French regional motorways departments (DDE) have been testing and using these kind of roads for quite a long time and I have used a lot of them.

You can't really imagine what you gain in visibility and grip without all the water on the road !

The main problem i remember of was freezing. Water caught in the road when freezing would grow in size and break the structure of the road into tiny bits. Once unfrozen, those bits would just go away with your road.
One way or another this issue has been solved. I don't really know how

Erica, the Pringle Creek road is crowned with good side drainage. You wouldn't see water collect on it under any circumstances, no matter what material it was made from. Strong Road, the one in the foreground, is also crowned, and the low point where the two roads meet wasn't well drained.

The big puddle you're seeing is because Salem didn't build new drain infrastructure for Strong Road - it has little to do with the new road surface. The difference at Pringle Creek is in the volume of runoff.

Question. Wouldnt Pollution be a factor? The runnoff through the road would bring along material in the road with it thus polluting the groundwater. Wouldnt the material used for the roads effect the water running through it?

Question. Wouldnt Pollution be a factor? The runnoff through the road would bring along material in the road with it thus polluting the groundwater. Wouldnt the material used for the roads effect the water running through it?