Roadway Preservation and Resurfacing Plan

Through the development of Port St. Lucie by the General Development Corporation (GDC), many of the City’s streets were constructed in the 1980’s and 1990’s. Asphalt pavement in Florida typically has a life span of 15-20 years. Ideally the City’s streets need to be resurfaced (repaved) every 15-20 years, which means that many of the City’s streets are coming up on their second repaving cycle. Currently, the City has approximately 917 centerline miles of roads, with 765 of those miles being local streets. Considering an optimistic 20-year life span, the City needs to resurface a little over 38 miles per year. With a 15-year life span, 51 miles need to be paved per year.

Another consideration is that as streets age, not only does the asphalt deteriorate, but so does the underlying foundation (base and subgrade). Many factors contribute to base failure such as high-water table, type of base constructed, vehicle volumes, and types of vehicles. Though roadway base typically has a longer lifespan than asphalt, it too must eventually be replaced or rehabilitated. Given that the City is relatively young, roadway base in most of the City’s local streets is still structurally sound. The alligator cracking that is seen throughout the City is simply reflective of the cracking of the underlying base. This reflective cracking can and will most likely be seen within a couple of years of repaving unless the base is also treated and/or repaired. Replacing the base material is very costly and is typically only performed once the base material loses its structural integrity and begins to fail. The cracking in the base and reflective cracking seen in the asphalt has little to no impact on the structural integrity of the street itself and should not be considered a structural issue.

Prior to 2015, roadway and street conditions throughout the City were evaluated by City Staff based upon a visual inspection. With approximately 917 centerlines miles (≈2160 lane miles), the inspection, documentation, evaluation, and then prioritization was a time-consuming and subjective task. In Spring 2015, the City contracted to have all the City’s roadways and streets evaluated objectively utilizing a laser road surface tester (LRST). The LRST collected data including, but not limited to, Roughness, Surface Distress, Alligator Cracking, Rutting, Patching, and Raveling. All these factors were taken into consideration to calculate the Pavement Condition Index or PCI, which is a widely used metric in pavement management to evaluate pavement condition. The PCI ranges from zero (0), which is failing to 100, which is new asphalt. The PCI information provided allowed City staff to empirically evaluate and prioritize the City’s repaving needs.

Ideally, the City’s streets would be repaved every 15-20 years, but this is not always possible due to budgetary constraints. The repaving program attempts to leverage all available funding to optimize the benefits to all City residents while providing equitable distribution among all Council Districts.

Utilizing the roadway PCI ratings, local streets with lower PCI’s in each Council District are targeted for resurfacing first, assuming the base is still intact and does not exhibit failure. Should the base shown signs of failure, the street will be identified for more extensive repairs and rehabilitation and will be considered for the Capital Improvement Program (CIP).

Additionally, an attempt is made to select an entire neighborhood or at least “blocks” of streets within a neighborhood that exhibit similar PCI’s. This provides for a higher production rate, meaning less inconvenience to the public, and it provides a consistent look throughout the neighborhood.

Current funding and estimated annual miles to be paved is shown in the table below. Thanks to the voters of St. Lucie County, a Half-Cent Sales Tax was approved in November 2018. The sales tax will provide funding for infrastructure projects, including resurfacing, for ten years.

The funding provided by the CIP’s resurfacing budget and the additional funds from the Half-Cent Sales Tax are both identified below. The complete list of streets can be found in the Repaving Master Plan(PDF, 2MB).

The budget and thus annual miles paved is subject to change as additional funding sources are identified. As funding and conditions change, this plan will be reviewed and updated annually.

Table 1:

(Bold text represents funds and miles provided by the Half-Cent Sales Tax.)

As pavement ages and base failures begin to occur, maintenance and rehabilitation become much costlier. Exhibit 1 shows the typical deterioration curve for asphalt pavement as well as relative costs for “Preservation”, “Maintenance”, and “Rehabilitation”.

Resurfacing roadways would fall into the “Reactive Maintenance” category and is middle-cost range. To extend asphalt life and defer resurfacing costs, thus reducing lifetime asphalt maintenance costs, the repaving plan includes preservation techniques such as rejuvenation.

As shown in Exhibit 1, “Pavement Preservation” (PP) can extend the useful life of asphalt pavement for a fraction of the cost of resurfacing if performed at the proper time. The 10-year paving plan currently allocates a percentage of the annual budget to PP from FY 21/22 onward.

• Pavement Condition Index Interactive Map

Exhibit 1:

Reflection cracking at joints and block cracking

Cracks in asphalt surfaces that occur over joints in concrete pavements and a pattern of cracks that divides the pavement into approximately rectangular pieces.

Most residential roadways in the City of Port St. Lucie were originally constructed using a Soil-Cement Base. This leads to the visible reflection and block cracking even shortly after asphalt resurfacing takes place. This type of cracking does not indicate roadway failure, an issue with the asphalt pavement or require repair. It is simply a “reflection” of what the constructed roadway base looks like beneath the asphalt.

Fatigue cracking

Occurs in areas subjected to repeated traffic loadings (wheel paths). Can be a series of interconnected cracks in early stages of development. Develops into many-sided, sharp angled pieces, characteristically with a chicken wire/alligator pattern in later stages.

Typically found on roadways which are more heavily traveled than residential roadways and most often, constructed using a Soil-Cement Base. Fatigue cracking will most times also be accompanied by various other distress types.

Edge cracking

Applies only to pavements with unpaved shoulders. Crescent-shaped cracks or continuous cracks which intersect or are near the pavement edge adjacent to the shoulder. Includes longitudinal cracks outside of the wheel path.

Typically seen in areas without concrete curb and gutter such as most residential roadways. Can also be found in areas with curb and gutter which have received an overlay of asphalt which has been raised higher than the existing edge of curb and gutter.

Longitudinal cracking

Cracks predominantly parallel to pavement centerline. Location within the lane (wheel path versus non-wheel path) is significant.

Often found in roadways which have been constructed with curb and gutter and a non-soil cement base.

Transverse cracking

Cracks that are predominantly perpendicular to pavement centerline.

The Repaving Master Plan(PDF, 2MB) focuses primarily on the maintenance and upkeep of the City’s local and collector roadways. However, for the purposes of this Master Plan recommendation, all the City’s roadways (arterials, collectors, & local) are being considered. Utilizing a pavement management modeling software, all applicable treatment scenarios (i.e., rejuvenation, milling and repaving, crack seal then milling and repaving, full depth reclamation, and full reconstruction) were evaluated to provide the most efficient treatment strategy at the proper time in the pavement life cycle.

Based upon the results of these models, maintaining the current citywide average PCI (64) would require approximately $6 Million per year for local and collector roadways. In addition to the $6 Million per year for local and collector roadways, the City will identify arterial roadways in need of repair, resurfacing, and/or rehabilitation independently. These roadways will then be budgeted on the CIP as standalone projects.

Over the past three years, the average Citywide PCI has reached a low of 63.0 and equalized in 2021. As of the 2022 publication the PCI has increased to 63.2 and with the currently proposed repaving budget (as shown in Table 1), which includes the additional funding from the voter-approved Half-Cent Sales Tax, the Citywide average PCI is projected to climb. Meaning that funding levels have reached a point that the required maintenance will be keeping pace with roadway deterioration. This assumes major roadways will still be addressed separately. This trend has allowed the infusion of a “Rejuvenation” technique into the plan, which will lower future annual rehabilitation costs by providing an extended pavement life cycle.

• Sandpiper Bay (South): Various residential streets
• Sandpiper Bay (Mid): Various residential streets
• Riverview (South): Various residential streets
• Oak Hammock: Various residential streets
• Rosser Reserve (East): Various residential streets
• Floresta Gardens (Mid): Various residential streets