The road plan is essentially made up of three components; maintenance, reconstruction, and stop-gap measures, which are all incorporated on an annual basis. Good pavement management would dictate that all of the good roads are maintained first with a limited budget. The reason for this is represented in the graph below. Pavement is very similar to the shell of your house. If you paint it regularly and keep it sealed we all recognize the benefit of it. If we allow water to seep into the wood and begin to rot the framing it would jeopardize the structural integrity of the house, which would make for very costly repairs. If you look at the graph below, you see a typical pavement degradation curve. In the first few years after a road is constructed it is easy and inexpensive to maintain it. The trick to good pavement management is to try to keep your roads in this condition as long as possible. Once the cracks become full-depth and too numerous to keep sealed, water will begin to enter the base gravel and break the roads down. At this point, the degradation curve gets steeper, the deterioration of the road accelerates and the repairs become more costly. Once a road is in complete failure the curve begins to flatten out. That road will not get much worse over time.
Because of this, DPW has a good maintenance program. Once a road has been reconstructed or repaved it is added to our annual crack sealing list. The object of crack sealing is to keep the water out of the gravel for as long as possible. The next layer of maintenance is an overlay. Over time, traffic wears ruts into the top coat of asphalt. The top coat is called the wear course. The purpose of this coat is just what the name suggests, it is a thin layer that provides a smooth ride, seals the base (structural) asphalt course, and provides an easily maintainable surface for DPW. Every 7 or 8 years DPW plans to add a new wear course to new and rebuilt roads, to keep the water draining from the surface, the ride smooth and the road maintainable. If left too long, then ruts will form in the road and it will need to be shimmed before it can be overlaid which adds to the cost.
The second component of the road plan is road reclamation. In 2001, the Select Board, DPW, the Budget Committee, and a very positive vote at the Town Meeting decided that the Town could not afford to start from scratch and build all of the roads to today's standards. At that time, a policy of reclaiming existing roads was adopted. See the Road Reclamation FAQ for more information on this process.
The final aspect of the road plan is the stop-gap measures. Stop-gap measures are simply a bandaid and not a true fix to the underlying structural road failure. DPW does not like spending money on stop gaps, however, many of the Town's roads are in such poor condition that they can no longer be maintained or politics dictate that the Town do something to hold the roads together until they can be rebuilt. This is really not a cost-effective measure, however, it is deemed necessary from time to time. "Shims" or "shimming a road" is considered a stop-gap measure that will only last 4 or 5 years at best.