To ensure that the economic analysis is clearly economically-justified as required by 23 CFR 668.109, select an analysis period based on the chart below.
| Functional Classification | Analysis Period |
|---|---|
| Local (most Tribal and Federally Owned Roads) | 30-years |
| Collectors | 40-years |
| Arterials | 50-years |
The analysis period is limited to account for uncertainty in:
The service life of the primary feature of the alternative will be used in the economic analysis. The following is a guide in determining the service life to use.
| Primary Feature | Service Life |
|---|---|
| Roadways and associated materials (e.g., pavement and riprap) | 35-years |
| Metal culverts | 30-50 years |
| Concrete culverts | 50-years |
| Concrete bridges | 50-100 years |
Metal culverts and bridges at the longer service lives require design measures to protect against corrosion.
While the service life of some elements of a facility may extend past the end of the analysis period, this does NOT change the analysis period. In the life-cycle cost analysis, the service life remaining at the end of the analysis period will be credited back to the initial cost of the alternative. The remaining service life may have two components:
