There are many factors that lead to the deterioration of a road. Sunlight (UV Rays) break down the asphalt. Freeze/thaw cycles cause the asphalt to shrink and expand leading to cracks. Frost's action heaves the roads. Traffic loading obviously affects the life of the pavement. Probably the worst enemy that a road can have is water. Getting water away from the roadbed is critical.
The other factor, particularly in New England is many of our roads were never properly constructed. They started as wagon roads in colonial times to get produce to the market. Over time they were widened and upgraded, however, never properly designed for today's traffic loads. There is a great video of the Life Cycle of a Highway that demonstrates this phenomenon.