ESA Essentials Part 3 - Condition Graphs

​Sometimes pavement management is not about selecting rehabs and planning new projects. Sometimes it is about defending those decisions in front of a town council or even an elected official. For those instances, a presentation showing data filled spreadsheet may not quite hit the nail on the head. Luckily, ESA generates several helpful visual aids that can help you demonstrate your pavement management successes, even when your audience sits blissfully unaware of the complexity of the tasks at hand.
 
Condition Graphs
 
The first thing you will want to understand is the pavement condition outputs from ESA. Three of the most helpful can be found in the Summary tab, $Plot tab, and the Current GFP tab.
 
The summary tab breaks down pavement condition by functional classification. Take a look at the example below:

​The summary tab list the pavement condition by pavement type and functional class, it also highlights overall PCI averages and Backlog percentage. Finally the total area is broken down by each of the aforementioned categories. For example: I can see that the Sample network has 48 miles of asphalt local roads that have an average PCI of 78.
 
Next lets look at the $Plot tab. This tab is best used to demonstrate the value of your pavement assets. Sometimes the best way to get someone’s attention about pavement management is to show them that there are millions of dollars at stake.

​The $Plot pie chart shows estimates for various costs associated with pavement work, such as drainage, sidewalk and ramp work, subgrade/base and more. The Miscellaneous costs are often contractor fees, and other such costs associated with doing work in your town. These costs are estimates and are not substitutes for project level design costs, but, nevertheless this is useful to hammer home just how much money your pavement network is currently worth. In our example town above it appears the total network is valued at approximately $124 Million. That is surely one of the town’s most valuable assets.
 
Finally, let’s take a look at the GFP tab and go over what IMS considers the “Metrics of Success”. Take a look at the following graph:

You probably noticed immediately that our example town has a very healthy condition distribution. This network satisfies all three metrics of success, Average PCI, % Excellent and %Backlog.
 
Pavement Condition Index (PCI) – The PCI score is a ranking assessment on the overall health of a pavement segment on a scale of 0 to 100. The network average PCI is a good global indicator of a network’s overall health. The average PCI score from agencies across the country is 60-65. Our example agency above blows way past that with an average PCI of 77.8, so they definitely exceed the first metric.
 
Percent of Excellent Roads – Roads with a condition category of Excellent are those that score between a PCI of 85 to 100. Generally we like to see an agency with around 15% of their in the excellent category. This indicates that the agency has been investing in their pavement network at somewhere near the steady state level. (The level of investment required to maintain the network average PCI) Our Sample network is sitting at 31% excellent roads, satisfying our second metric.

​Backlog –Backlog is the Very Poor and Poor roads (between a PCI of 0 and 40) that represent a portion of the network in need of extensive rehabilitation such as full and partial reconstruction.  Using sound pavement management and finance principles, a very healthy network will have a backlog of 12% or less. The example network above has only 1% backlog, easily satisfying this metric.

Hopefully this gives you enough information to comfortably review and discuss your pavement network’s current condition. Next week we will run our first budget and take a look at some of the outputs.