JT- interesting stuff. There is a slight but worrying trend amongst airport engineers who question the need for the runway to be homogeneously provided across the full width. They see the rubber deposits in the touchdown zone concentrating around the centreline (and forming what is almost a textbook example of normal distribution with quite a small standard deviation). This leads them to believe that the outside edges are never used, and so economies can be had in the upkeep of the runway.
There are certain fine tuning things that can be safely done, such as reducing the pavement depth at the runway edges based on the reduced trafficking at the edge. However when this thinking leads to economies like grooving only the central 30m on a 45m wide runway, or resurfacing only the central 15m or 22m, then the whole thing gets marginal. This discussion will be useful stuff to throw into the debate. Many years ago, I managed to drift a 707 off the runway into the grass of the runway strip during landing, which gave me an everlasting understanding of the value of width. The DoT ATG stuff is more scientific and easier to use in teaching.
Look forward to catching up over an ale - I'll drop you a line next time I'm travelling east of the rabbit proof fence.