Seems like the bad roads are a combination of a poor foundation and cheap asphalt.  Mist of the mainland roads seem to be a combination of asphalt and cement.  Although the mainland roads are more noisey I rarely see any cracks or potholes in them. 

Also it is frustrating to be caught in traffic while the roads are being repaired knowing that the road will not last for more than a few years.  I wouldn't mind it so much if they put down a better product.