Every long-term infrastructure plan rests on an assumption about how fast things fall apart. Making that assumption explicit is what turns a wish list into a forecast.
The shape of the curve
A typical asphalt pavement loses roughly 40% of its condition in the first 75% of its life, and the remaining 60% in the last 25%. The curve is flat, then steep.
The practical consequence: a dollar spent during the flat section buys several years of life; the same dollar spent after the drop barely moves the needle, because the required treatment is now structural.
What changes the curve
Curves are not universal. They vary by surface type, traffic loading, subgrade, drainage and climate.
- •Surface and structure — asphalt, concrete, chip seal and composite all age differently
- •Traffic loading — heavy truck routes deteriorate on a much shorter horizon
- •Drainage — water reaching the base is the single biggest accelerator
- •Climate — freeze-thaw cycles and extreme heat both shorten life
Calibrating with your own data
Default curves are a starting point. Once you have two or three inspection cycles, you can compare predicted to observed condition and adjust the curve per asset class.
This is why consistent inspection dates matter as much as inspection scores: without dates, there is no time axis to calibrate against.
Turning curves into decisions
With calibrated curves, scenario analysis can answer the questions that actually get asked in budget season: what does flat funding do to network condition over ten years, what does it cost to hold today's condition, and what does one year of deferral add to the total bill.
Frequently asked questions
- How much data do we need to calibrate curves?
- Two inspection cycles on the same segments is enough to start adjusting. Three or more produces reliable class-level curves.
- Can curves be set per asset type?
- Yes. Deterioration curves, unit costs and treatment triggers are configured per asset class in AtlasView.