Pavement Preservation


Pavement Preservation

None of us want to attempt to drive on roads like the one in the photo above, to help prevent that, in 2012, the City of Duluth adopted a Pavement Preservation and Management Plan to better manage our road system. This program will emphasize the importance of early intervention through the adoption of proactive maintenance strategies. Simply resurfacing a street anymore is not the most cost efficient or best method for long term preservation of that roadway.  We must switch our mindset from repairing the worst roads first, which depletes budgets quickly.  In addition, a road already in the poor category will cost little more to rehabilitate in a few years (and the method of rehab will not change), but will allow us to maintain more good and fair streets, affecting more miles of street per dollar.  Our goal is to not let roads fall below a certain PCI (Pavement Condition Index) rating. To accomplish this, we must spend money on keeping the good roads good and not allowing them to fall into the fair or poor category, where we will have to spend more money to get them back to good. It is a proven fact that every dollar spent now on pavement preservation can save up to six dollars in the future. In addition to the long term cost savings, pavement preservation and management strategies pay dividends by reducing greenhouse gas emissions associated with both vehicle use and roadway construction. This program is currently funded by the Special Purpose Local Option Sales Tax (SPLOST).

As shown in this graph, substantial savings can accrue with a well-planned pavement preservation program. It is similar to preventive maintenance on your home or car; you've made an investment and regular maintenance protects that investment. Roads are an investment as well; an investment in the commercial and residential viability of a community. Preservation programs also have the potential to reduce traffic delays by using faster repair techniques as well as increasing safety for the public and workers by decreasing the amount of time roads are closed.


An assessment of all streets within the City was completed in Summer 2012 and each street was given a PCI-Pavement Condition Index rating, between 0-100, with 0 being the worst (or a completely failed street) and 100 being the best (or a brand new street). Upon completion of the assessment, our street network average PCI was 46. Over the last year, through minor projects and maintenance, we have increased our street network average to 53. Below is a graph showing the miles of streets by current condition.


Pavement Condition Ratings are as follows:

  • Very Good - 100-70
  • Good - 69-50
  • Poor - 49-25
  • Very Poor - 24-0
Our goal is to get our street network average PCI to 70 in the next 10 years and maintain that average (funding permitting).  It is important to note that this is a network (or City-wide) average, it does not mean that every street in the City will be at 70 in 10 years, only that the network will reach that level, which by default, means that almost every street in the City will be in better condition than it is now.

Examples of Streets and Ratings

Very Good rated streets are where preservation will make the most difference in extending the life of the road.


This is a very good street. The  PCI rating is 90;,meaning it has very few (if any) signs of distress.  In this condition, a rejuvenating agent would be ideal.


 This is a very good street; the PCI rating is 74; meaning it has low levels of distress, maybe some minor cracking or weathering (wearing away of the asphalt binder and fine rock). This street would certainly benefit from receiving a preservation treatment to prevent further deterioration. Some examples might be: crack sealing/filling, a rejuvenating agent or microsurfacing or slurry seal,the method would depend upon the amount and severity of distresses.


This is a Good street; the PCI rating is 68; meaning distress levels are increasing. The street will certainly exhibit minor cracking (either block or minor load cracking), raveling (the dislodging of coarse rock) and usually weathering.  This street would benefit from a microsurfacing or slurry seal application,(depending upon the severity of the cracking) or other ultra thin topping.If addressed quickly enough, further deterioration can be prevented. Either of these methods will add several years to the life of the road at a very reasonable cost.


This is a Good street; the PCI rating is 50, meaning distress levels have worsened.The street will exhibit alligator cracking, probably combined with load cracking, raveling,weathering, small patches and possibly some small potholes. Roads at this level will begin requiring reconstructive work. Depending on the base underneath the road and the thickness of the asphalt,it may be a candidate for in-place recycling or deep patching of all the bad areas,then a thin overlay. Each method gets progressively more expensive per square yard.


This is a Poor street; the PCI rating is 34.  It will exhibit numerous distresses; weathering, potholes, patches, rutting and various types and levels of cracking. Depending on the base, thickness of asphalt and depth and amount of cracking and rutting;the road might be saved with a combination of deep patching, milling and a thin overlay; it is more likely, however, that the road will require full rehabilitation or full depth reclamation, which involves grinding up the asphalt surface and part of the base, remixing everything and replacing, then adding a top layer of new asphalt.


This is Very Poor street; the PCI rating is 6.  It will exhibit all the distresses severe cracking, rutting, potholes, patches, severe weathering and poor drainage.This street will require full depth reclamation, possibly including some soil stabilization as well as crown correction and replacement of drainage systems. At this level it is better to let the street continue to deteriorate for a few years,and save up the money to repair, as the method of reconstruction will not change and costs will only slightly increase.