michaelcycle, your remarks, well informed, logical, and nuanced, are well received. Thanks. More here than I've learned from a couple of visits with TDOT engineers. Are you one by chance?

I especially like your argument for fine aggregate use on shoulders. A 3 mile stretch of state highway near where I live, with a smooth shoulder paralleling course chip seal, was recently resealed. They covered all with the course aggregate. Guess it was easier than not, tho the shoulder was in good condition.

A lot of what TDOT does is a mystery to a layman. This includes why they chose 3 or 4 different types of material for a short stretch of highway. US 59, a major highway from Houston north, is variously paved with concrete, asphalt, fine and course aggregate, sometimes different material in adjacent lanes.

Do you by chance have any reference links to objective data showing course aggregate surfacing to be safer than fine, or concrete, or asphalt? Sure, the gripping characteristics are
probably better, but does this really translate into an actual reduction in the accident rate?

As I become better educated on this relative to TDOT, I want to reexamine my impression that the use of course aggregate is pretty limited in other states.

Thanks.