Technical_Memo:_Pavement_Maintenance_and_Rehabilitation_Budget_Scenarios_for_City_of_Urbana.pdf

Technical Memo Study Title: Urbana PMS Support Task # 3 Task/Subtask Title: Preservation, Maintenance, and Rehabilitation Guide Date Submitted to City of Urbana: November 3, 2023 Date Approved by City of Urbana:

Prepared for the City of Urbana, Illinois

This document is submitted by Applied Pavement Technology, Inc. (APTech) and is fully privileged. Any dissemination of the information herein must first be approved in writing by the City of Urbana, IL. The conclusions expressed or implied herein are those of the consultant and may not agree with those of the City of Urbana, IL.

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Contents

USING PAVER TO EVALUATE PAVEMENT MAINTENANCE AND REHABILITATION BUDGET SCENARIOS FOR THE

CITY OF URBANA, ILLINOIS

BACKGROUND

PAVER CUSTOMIZATION

MAINTENANCE AND REHABILITATION SCENARIOS

SUMMARY

USING PAVER TO EVALUATE PAVEMENT MAINTENANCE AND REHABILITATION

BUDGET SCENARIOS FOR THE CITY OF URBANA, ILLINOIS

BACKGROUND

The City of Urbana (City) hired APTech to evaluate budget scenarios for their over 22 million square ft paved road network. The purpose of this analysis was to assess the long-term effect the current budget will have on the conditions of the network.

This memorandum discusses the necessary PAVER pavement management software customization to complete the various maintenance and rehabilitation (M&R) budget scenario analyses requested by the City.

PAVER CUSTOMIZATION

PAVER is a pavement management software tool that is used to store pavement inventory information, calculate pavement conditions using visual assessment data, develop models to predict future pavement performance, store past performance data, and develop basic M&R plans. The software was configured to reflect the specific conditions and needs for maintaining the City’s pavements. Customizing PAVER is essential to ensure the analysis results are meaningful and applicable to the City’s needs. APTech defined the PAVER inputs using past pavement management experience and information received from the City.

As further described below, the customization of the City’s PMS is broken down into the following activities:

• Scenario policies and assumptions

• Unit cost update

• Available budget

• Prioritization guidelines

Scenario Policies and Assumptions

The following are the assumptions for the scenario approach:

• Parking Lots were excluded from the analysis. From conversations with Public Works staff, these sections are not commonly targeted for M&R with the budget used for this analysis.

• Brick-surfaced roads were excluded from the analysis. There is no PCI available for this surface type and maintenance strategies for these structures are limited.

• Stopgap maintenance was not accounted for in the scenarios. Reactive maintenance to maintain the functionality of failing pavement sections is carried out as needed.

• Preventive M&R (e.g., joint sealing, crack sealing, and localized patching) was included in the scenarios. These are treatments applied to a pavement generally in good condition with the primary objective of slowing the rate of pavement deterioration.

• Global preventive M&R treatments are more typically referred to as surface treatments (e.g., slag seal, slurry seal, micro surfacing, etc.) and are a cost-effective way to extend pavement life when the pavement surface is still in good condition. The City’s current practice is to use slag seal treatments for those roads in the network that currently have Surface Treatment (ST) surface type.

• The critical Pavement Condition Index (PCI) represents the condition level below which major maintenance and rehabilitation (M&R) work should be triggered. Major M&R is typically defined as a global activity, such as an overlay or reconstruction, that would return the pavement to basically “new” condition and would result in a PCI of 100 (no distress) if implemented. A sensitivity analysis was carried out to define the critical PCI for all City-maintained roads.

Unit Costs

Based on recent high rates of inflation and with the agreement of the City, APTech inflated the existing 2019 treatment cost data by thirty percent and updated the cost by PCI tables for rehabilitation and preventive maintenance activities by functional classification and surface type. These costs were used during the budget scenario analysis and comparison. Additionally, a 3 percent annual inflation rate was incorporated into the analysis.

In general, the costs for rehabilitating pavements with a PCI below 20 represent the cost of reconstruction. For PCIs between 20 and the critical PCI the costs generally represent the cost of asphalt overlay with varying amounts of pre-overlay repairs (assuming pre-overlay patching of approximately 5 percent of the section)for asphalt-surfaced (AC) roads and slab replacements for concrete-surfaced (PCC) roads. Table 1 shows the cost per square by PCI range for localized preventive maintenance activities. while Costs vary by surface type due to materials and labor; AC has historically been less expensive than PCC because the asphalt mix is less expensive and requires less labor than a PCC road that typically requires steel reinforcement which adds to the already higher cost of the concrete mix.

Additionally, costs also vary by functional classification due to the need for thicker cross sections to withstand higher traffic loadings on arterial and collector roads than on local roads. Table 2 shows the cost per square yard by PCI rating for major M&R activities for AC and PCC for each functional classification and surface type.

Table 1. Preventive Maintenance Cost per square yard by PCI Rating.

PCI PCC AC and ST 0 $4.68 $7.37

10 $4.68 $7.37 20 $4.68 $7.37 30 $4.68 $7.37 40 $4.68 $3.63 50 $4.68 $1.52 60 $4.68 $0.23 70 $1.99 $0.12 80 $1.17 $0.12 90 $0.12 $0.12

100 $0.00 $0.00

Table 2. Major M&R Cost per square yard by PCI Rating.

PCI

Arterial/Collector1

PCI

Local1

PCI

Surface

Treated2 PCC AC and ST PCC AC and ST 0 $280.80 $105.30 0 $196.56 $73.71 0 $23.40

10 $280.80 $105.30 10 $196.56 $73.71 10 $23.40 20 $280.80 $105.30 20 $196.56 $73.71 20 $23.40 30 $70.20 $43.88 30 $58.50 $27.50 30 $23.40 40 $42.12 $43.88 40 $42.12 $27.50 40 $23.40 50 $42.12 $43.88 50 $42.12 $27.50 50 $23.40 60 $42.12 $43.88 60 $42.12 $27.50 60 $23.40 70 $0.00 $0.00 70 $0.00 $0.00 70 $0.00 80 $0.00 $0.00 80 $0.00 $0.00 80 $0.00 90 $0.00 $0.00 90 $0.00 $0.00 90 $0.00

100 $0.00 $0.00 100 $0.00 $0.00 100 $0.00 1 Street classification as defined by City of Urbana standards.

2 Surface treated roads as defined by City of Urbana standards.

As previously mentioned, the City of Urbana’s current practice calls for the use of slag seals only on roads that currently already have an ST surface. The M&R scenarios recommend these treatments on roads with PCIs between 90 and 55The time to reach the pre-treatment condition (treatment life) is 2 years and the application interval is 5 years; a unit cost of $23.40 per square yard was used. City practice also calls for this treatment when the PCI of ST-surfaced roads falls below the critical PCI; this is also shown in table 2 in the surface treated roads column.

Available Budget

The City anticipates annual funding of $1.8 million from the state motor fuel tax fund and $700 thousand from the local motor fuel tax fund for the 10-year analysis period.

Prioritization Guidelines

Prioritization is a technique used to determine which M&R activities should be performed when there is insufficient funding to perform all necessary work. Development of prioritization guidelines helps assign funding where it is most effectively used.

Priorities should consider all factors relevant in determining the relative importance of various pavements. The priorities used for the City network are based on the functional classification of the road and are as follows:

• High priority – arterial roads. Includes roads which serve as the main distributing arteries for traffic.

• Medium priority – collector roads. Includes roads which supplement the arterial roads by providing access to, between, and within the various functional areas.

• Low priority – local roads. Includes all roads not classified as arterial or collector roads.

Once ranked by functional classification, when a constrained budget (insufficient budget to fund every need) analysis is performed, PAVER prioritizes projects in the following order:

1. Preventive maintenance.

2. Global maintenance

3. Major M&R.

Critical PCI Sensitivity Analysis

Due to the role of the critical PCI in PAVER’s budget forecasting capabilities, a separate analysis for the current budget and a target PCI of 60 for the network was carried out. Each scenario was analyzed for critical PCI values of 60, 55, 50, 45, and 40.

The current budget of $1.8 million from the state motor fuel tax and $700 thousand from the local motor fuel tax was analyzed first. Table 3 shows a comparison of the backlog, forecasted PCI, and change in PCI for the network throughout the 10-year analysis period.

Table 3. Comparison of cost and condition for current budget for varying critical PCI values.

Funding Scenario

Average Yearly Budget

Total 10-Year Funded Costs

Remaining M&R Backlog in 2032 Total Funded +

Backlog

Forecasted PCI in

Change in PCI

Critical PCI of 60 $2,500,000 $24,971,539 $137,925,163 $162,896,702 46.8 -6.2 Critical PCI of 55 $2,500,000 $24,948,866 $129,469,948 $154,418,814 47.0 -6.0 Critical PCI of 50 $2,500,000 $24,949,945 $123,296,769 $148,246,715 47.2 -5.8 Critical PCI of 45 $2,500,000 $24,961,621 $114,458,847 $139,420,468 47.1 -5.9 Critical PCI of 40 $2,500,000 $24,944,963 $107,339,980 $132,284,943 46.6 -6.4

It is noteworthy to mention that the remaining M&R backlog is expected to be lower as the Critical PCI decreases. This is due to there being fewer sections that fall under the need of costly rehabilitation and reconstruction.

In this analysis, varying the Critical PCI doesn’t seem to have a considerable effect on the forecasted PCI.

The largest difference between the analysis is six tenths of a point between the Critical PCI’s of 50 and 40, and between a Critical PCI of 55 and 45 the difference is within two tenths of a PCI point.

Because this scenario doesn’t provide enough information to decide on a critical PCI, targeting an overall area weighted average PCI of 60 for the network by varying the Critical PCI was analyzed. In order to have an accurate comparison, the software was allowed the same tolerance for every scenario, thus all values have a forecasted PCI slightly above the target PCI of 60. Table 4 shows a comparison of the backlog, forecasted PCI, and change in PCI for the network throughout the 10-year analysis period.

Table 4. Comparison of cost and condition for a target PCI of 60 for varying critical PCI values.

Funding Scenario

Average Yearly Budget

Total 10-Year Funded Costs

Remaining M&R

Backlog in

Total Funded + Backlog

Forecasted PCI in

Change in PCI

Critical PCI of 60 $7,080,000 $70,828,081 $91,111,119 $161,939,200 62.9 9.9 Critical PCI of 55 $7,512,000 $75,124,192 $85,481,644 $160,605,836 62.7 9.7 Critical PCI of 50 $8,000,000 $79,998,309 $77,531,272 $157,529,582 62.6 9.6 Critical PCI of 45 $8,540,000 $85,421,988 $64,869,939 $150,291,927 62.0 9.0 Critical PCI of 40 $9,680,000 $96,806,867 $45,014,612 $141,821,479 62.0 9.0

This analysis shows that it will cost less to reach a target PCI of 60 as the critical PCI increases. This is mainly due to applying less costly maintenance and preservation to roads before they are severely deteriorated and would require more costly rehabilitation and reconstruction.

In conversations with the City, it was decided that using a Critical PCI of 55 is realistic and more in line with the agency’s current practice.

MAINTENANCE AND REHABILITATION SCENARIOS

M&R scenario analysis allows for a simple comparison of different budgets and condition targets. These were developed considering the City’s primary objective of preserving its roadway network with programmed and available funding.

The preliminary analysis was carried out to assess the impact of higher percentages of localized maintenance and repair with the current funding over a 10-year period. These scenarios were optimized by reincorporating any surplus from the global maintenance funds onto the major M&R funds. Below are the three analyzed scenarios; percentages are based on the overall funding available.

• 10% Localized maintenance, 20% Global Maintenance, and 70% Major M&R

• 20% Localized maintenance, 20% Global Maintenance, and 60% Major M&R

• 30% Localized maintenance, 20% Global Maintenance, and 50% Major M&R

Figure 1 illustrates the change in PCI over the analysis period under these three scenarios. Table 4 provides a comparison of the total funded plus backlog value for each scenario, as well as the forecasted PCI for each, and final optimized percentages per work type.

Figure 1. Impact of different localized budget levels on PCI.

2023 2024 2025 2026 2027 2028 2029 2030 2031 2032

Fo re ca st ed P av em en t C on di tio n

In de x (P

CI

Year

10% Localized 20% Localized 30% Localized

Table 4. Comparison of total accumulated cost and change in PCI over 10 years at different localized budget levels.

Funding Scenario

Average Yearly Budget

Total 10-Year Funded Costs

Remaining M&R Backlog in 2032

Total Funded + Backlog

Forecasted PCI in

Change in

PCI

10% Localized 8% Global 82% Major $1.8M State

Motor Fuel Tax & $700K Local Motor

Fuel Tax

$24,963,896 $129,335,637 $154,299,533 47.0 -6.0

20% Localized 9% Global 70% Major

$24,946,216 $132,174,544 $157,120,761 46.3 -6.7

30% Localized 10% Global 60% Major

$24,972,253 $135,262,468 $160,234,721 45.5 -7.5

The Total Funded + Backlog column shows that as less is spent annually on Major M&R, the network backlog cost increases, and the network condition declines. Therefore, assigning 10 percent of the budget to localized preventive maintenance was selected as the most cost-effective use of the available funds and implemented in the budget analysis comparison.

The following budget scenarios over a 10-year period were analyzed:

• Current funding by prioritizing work on arterials and collectors. Funds were allocated to meet the agency’s targets of 70 and 65 for arterials and collectors, respectively. Remaining funds were allocated to local roads.

• Funding required to maintain current area-weighted average network PCI of 53. The goal of this scenario is to not only maintain the area-weighted average condition of the network, but also of each functional classification. To achieve this, area-weighted average PCI’s of 60, 61, and 49 were maintained for arterial, collector, and local roads, respectively.

• Funding required to reach an overall area-weighted average network PCI of 60. This area-weighted average target is to be reached by meeting the individual agency targets for each functional classification. Targets PCI’s for arterial, collector, and local roads are 70, 65, and 56, respectively.

Additionally, a 20-year scenario was included in the analysis. This analysis predicts the funding required to reach an overall area-weighted average network PCI of 60 in 10 years, then maintaining it at that level over the following 10 years.

The starting date (year 1) for the analysis was October 2023, and the ending dates were October 2032, and October 2042 for the 10- and 20-year scenarios, respectively. Figure 2 compares projected network conditions over time for three 10- year budget scenarios, Figures 3, 4, and 5 show the area-weighted average condition for the network and each functional classification throughout the analysis period for the current funding, maintaining current condition, and target condition scenarios, respectively.

Figure 2. Impact of different budget levels on PCI.

2023 2024 2025 2026 2027 2028 2029 2030 2031 2032

Fo re ca st ed P av em en t C on di tio n

In de x (P

CI

Maintain Current Condition Target PCI of 60 Current Funding

Figure 3. Impact on PCI by functional classification with current funding.

Figure 4. Impact on PCI by functional classification with funding required to maintain the current area-weighted average network PCI of 53.

2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 Network 53 53 52 51 51 50 49 48 48 47 Arterial 63 65 67 68 69 69 70 70 70 70 Collector 63 63 64 64 65 65 66 66 65 65 Local 50 48 46 45 44 42 41 40 39 38

PC

I

Year

2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 Network 54 54 54 54 53 53 53 53 53 53 Arterial 61 61 61 61 61 61 60 60 59 60 Collector 62 62 62 62 63 62 63 62 61 61 Local 51 51 51 50 50 50 50 50 49 49

PC

I

Figure 5. Impact on PCI by functional classification with funding required to reach an overall area-weighted average network PCI of 60.

Figure 6 illustrates the change in PCI over the 20-year analysis period while Figure 7 shows the area-weighted average condition for the network and each functional classification throughout the 20-year analysis period.

2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 Network 55 56 57 58 58 59 60 60 60 60 Arterial 63 65 67 68 69 69 70 70 70 70 Collector 63 63 64 64 65 65 66 66 65 65 Local 52 52 53 54 55 55 56 57 56 56

PC

Figure 6. Change in PCI over 20-year analysis.

Fo re ca st ed

P av em en t C on di tio n In de x

(P

CI

Figure 7. Impact on PCI by functional classification with funding required to reach an overall area-weighted average network PCI of 60 in 10 years and maintaining it at that level over the following 10 years.

2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 Network 55 56 57 58 58 59 60 59 60 60 60 60 60 60 61 60 61 60 60 60 Arterial 64 68 71 72 74 75 80 76 78 79 79 79 78 77 76 75 74 74 74 72 Collector 62 60 59 57 56 54 52 53 52 52 51 55 59 61 64 64 65 65 65 67 Local 52 52 53 54 54 55 56 55 56 56 56 56 56 56 56 56 56 56 56 56

PC

Due to software limitations, it was not possible to separate arterials and collectors for this scenario.

Therefore, an improvement in the condition of arterial roads at the expense of the condition of the collector roads over the first ten years of the analyses period can be observed in Figure 7. However, beyond those 10 years the condition increases and exceeds the target for the two functional classifications. Nonetheless, the overall network targets are met throughout the analysis period. Table 4 compares the total funded plus backlog value for each scenario, as well as the forecasted PCI at the end of the analysis period. This table is valuable in that it displays the total accumulated cost of deferring repairs over time. The “Remaining M&R Backlog in 2032” column shows that as less is spent annually, the backlog increases and the network condition declines. It is noteworthy to mention that the remaining backlogs for both the “Target PCI of 60” and “Maintain Current Condition” scenarios only contain Major M&R work; all recommended preventive and global maintenance have been addressed.

This is a part of the “preservation first” approach that PAVER uses in its prioritization scheme when carrying out budget requirement scenarios. On the other hand, the current funding scenario has limited resources available for each maintenance category; therefore, the backlog will include work for any category where the funding is insufficient to cover the cost of the recommended work.

Table 4. Comparison of total accumulated costs over time at different funding levels.

Funding Scenario

Average Yearly Budget

Total 10-Year Funded Costs

Remaining M&R

Backlog in

Total Funded + Backlog

Forecasted PCI in

Change in

PCI

Target PCI of 60 $6,860,000 $68,620,854 $95,681,593 $164,302,446 60 7 Maintain Current Condition $5,010,000 $50,102,157 $121,454,043 $171,556,200 53 0 Current Funding $2,500,000 $24,945,810 $133,632,346 $158,578,156 47 -6

Funding Scenario

Average Yearly Budget

Total 20-Year Funded Costs

Remaining M&R

Backlog in

Total Funded + Backlog

Forecasted PCI in

Change in

PCI

Reach Target PCI of 60 in 10 years and maintain condition over the following 10 years

$6,900,000 $138,074,763 $115,890,549 $253,965,312 60 7

SUMMARY

This memorandum provides information on the process involved in the generation of budget scenarios for the City from the PAVER Pavement Management Software. The following summarizes the findings from the analysis:

• If the current funding is maintained, the area-weighted average PCI for the network is projected to drop by 6 points to 47 by 2032 (year 10). Arterial and collector roads will reach their targets of 70 and 65 respectively, but the PCI of the local roads will decrease by 11 points.

• The required annual funding to maintain the current PCI of 53 (60, 61, and 49 for arterial, collector, and local roads, respectively) over the next 10 years is $5 Million. Because of current substantial M&R needs, the cost to maintain the network at its current level is fairly high.

• The City requested a budget projection scenario to achieve an area-weighted average PCI value of 70 for arterial, 65 for collector, and 56 for residential roads (overall of 60 for the network). To achieve this value over 10 years would require an annual budget of $6.86 Million. A backlog of needs would remain that would have to be addressed over time to prevent declining network conditions beyond that.

• To reach a network area-weighted average PCI goal of 60 by year 10 and maintain it over the following 10 years (maintaining the targets by functional classification set forth by the City), an annual budget of $6.9 Million would be needed.

The condition of the network has reached the point where the rate of decline is greater than the current funding can sustain. If the City desires to overcome the declining trend, additional investment in road M&R is needed.

The PAVER database established for the City can be used to perform additional analyses and evaluate different strategies. To do this the City will need to maintain the PMS by periodically updating work history information and collecting updated condition data.