Parking lots
What is a pavement condition index?
A pavement condition index is a score from 0 to 100 that rates a paved surface from the distresses visible on it, following ASTM D6433.
The numbers
- The scale runs 0 to 100, where 100 is a surface with no visible distress.
- It is rated from what a person can see and measure: cracking, raveling, rutting, patching, potholes.
- The method is set out in ASTM D6433.
- The score is used to rank a portfolio, not to price one lot.
What it is measuring
Somebody walks the surface in sample areas and records what is wrong with it: the kind of distress, how severe it is, and how much of the area it covers. Those get combined into one number between 0 and 100.
It is deliberately not an opinion about what should be done. It is a description of condition that two different people should arrive at within a few points of each other, which is exactly what a score has to do if it is going to be compared between properties and between years.
Why an owner would want one
The value shows up when there is more than one lot. A school district, a municipality or a company with twelve sites cannot fund everything, and the argument about which lot goes first is much shorter when every lot has a score taken the same way.
It also shows the trend. A lot that went from 71 to 64 in two years is telling you something a photograph does not, and it is the sort of line that survives a budget meeting.
What it does not tell you
It is a surface rating. It does not see the base, it does not see the drainage, and it does not know that the low area by the dumpster is fed by a downspout. A score of 80 on a lot with a failing catch basin is accurate and misleading at the same time.
For a single property, walking it with somebody who works on lots gets you further than a score does. For twenty properties, the score is how you decide which one to walk first.
Where these numbers come from
- ASTM D6433, Standard Practice for Roads and Parking Lots Pavement Condition Index Surveys.