Sir George Cayley,
No problems. In a purist engineering sense, linking performance credits with micro/macro texture values as opposed to whether the surface is grooved is technically more correct. But I think the grooving approach is better. When dealing with people, a purist engineering approach may not always be best. Macrotexture is a subtle concept and is not easy to see, not often measured, and (as I know from experience) capable of being distorted, disputed, mis-interpreted and generally twisted. I’ve seen this from all sorts of technical people, both on airports as well as high speed motorways/freeways.
I like grooving because it is simple (and the same is true for porous asphalt). The pilots can see it is there. The airport can see it is there. The authorities can see it is there. No arguments. And it works. Grooving worked at BRS. As soon as the new runway overlay was being immediately grooved, the complaints and incidents stopped. And there hasn’t been one since. Imagine if someone was trying to sort out the BRS problem if grooving was not available as a strong tool. Imagine trying to argue the subtleties of macrotexture with counter arguments about high friction results and so on. Not something as easily done.
I think that grooving is one slice of the James Reason model of Swiss Cheese. Take away that linkage between grooving and performance, and pretty soon you’ll have airports taking away grooving, and taking away that slice of Swiss Cheese.
I know that airports do not like friction treatments such as grooving or porous asphalt. They are expensive, they have a comparatively short life, and they require expensive routine maintenance. They do not add to the capacity of the airport, they don’t make the runway longer or wider, they don’t add to the structural capacity of the pavement, and they won’t let more planes take off. Airports can’t charge extra for them, and can’t rent them out. The airports provide friction treatment now because they have to.
I don’t think macrotexture is a strong enough argument to keep all of the airports grooving. So airports would start dispensing with grooving / friction treatment given a small gap to do so. I know they would based on many years experience of arguing the cost of runway overlays. Take the grooving slice off the Swiss Cheese, and it becomes that much easier to fit the line all the way through the Swiss Cheese to the accident.