Memorandum
City of Lawrence
Public Works Department
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TO: |
Dave Corliss, City Manager Debbie Van Saun, Assistant City Manager Charles Soules, Director of Public Works |
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FROM: |
Dena Mezger, Assistant Public Works Director Steve Lashley, Project Engineer- Infrastructure Management |
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Date: |
4/20/07 |
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RE: |
Pavement Maintenance Program Update & Evaluation |
Background
In 2005 the first pavement rating cycle was completed for all streets in the city. The rating was the first step in establishing a more formalized ongoing pavement maintenance program. (Copies of earlier reports outlining the results of the first rating cycle are available if needed.) A second evaluation and rating of 25 percent of the city’s streets was completed in February 2007. Information from the second rating cycle is being used to evaluate the effectiveness of the pavement maintenance program. The second cycle generally covered streets in the area south of 23rd Street.
Program Goals
The initial goal of the Pavement Maintenance Program was to prevent further deterioration of streets beyond the point at which preventative maintenance measures would no longer be cost effective. The critical point has been defined as a Pavement Condition Index (PCI) of 65 for arterials, 60 for collectors, and 55 for residential streets. Streets with PCIs below those values have been termed “unacceptable.” The first rating cycle indicated that 31.5% of streets in the city fell into the “unacceptable” range. The initial program recommended a mill and overlay treatment for arterials with PCIs in the range of 65-74, for collectors with PCIs in the range of 60-67 and for residential streets with PCIs in the range of 55-60 over a three year period from 2006 through 2008 to prevent more streets from falling into the unacceptable category. The PCI ranges for recommended improvements were based on initial estimated deterioration rates for the various classes of streets.
Program Funding and Progress
In late 2005 it was estimated that a total of $17.3 million would be needed ($6.0M in 2006, $6.4M in 2007, and $4.9M in 2008) for the contracted mill and overlay program to prevent the “borderline” streets from being downgraded to unacceptable condition. This amount did not include any funding for crack sealing or microsurfacing programs (generally used on streets with higher PCIs), major curb and gutter replacement (initially estimated at $12.5M), nor Street Division funding for routine asphalt and concrete pavement maintenance activities. Additional funding was recommended for those programs.
A funding summary for street maintenance from the 2007 budget is at the end of this report. With those funds the following maintenance has been, or will be, completed by the end of 2007.
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Contracted Maintenance |
2005 |
2006 |
2007 (proposed) |
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Mill & Overlay, miles |
9.80 |
12.80 |
7.52 |
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Crack Sealing, pounds |
75,000 |
386,580 |
225,000 |
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Microsurfacing, miles |
0 |
0 |
12.76 |
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Curb Replacement, miles |
8.1 |
10.2 |
6.4 |
In addition to the maintenance programs, several other street projects are planned to begin in 2007 or are already underway. The projects will address maintenance issues and positively impact condition ratings where the work is being done. Those projects include 2nd and Locust, Wakarusa and Clinton Parkway (in association with the Miracon project); 4th Street, Maine and Michigan as part of the Lawrence Memorial Hospital project; and both Kasold capital projects.
Impact of Program
The impact and effectiveness of the pavement maintenance program can be estimated based on several factors determined through the pavement rating system. One measure is the change in the average PCI. Another measure is the change in the rate of deterioration of the pavements. The deterioration rate represents the reduction in PCI each year as the pavement ages and wears. A large negative number indicates a rapidly declining pavement condition. Overall progress of the program may also be reflected by the change in percentage of streets with PCIs in the unacceptable range.
Average PCI
The average PCI for all streets established during the initial rating cycle was 69.0. Taking into consideration the maintenance performed since that time, the continued deterioration of other streets, and the results of the second rating cycle, the average PCI for all streets is anticipated to be 66.2 at the end of 2007. However, the averages just for the 25% of streets rated during Cycle Two of the condition rating process (south of 23rd Street), were also calculated separately. Since many of the street segments in the second cycle had been crack sealed, and a few milled and overlaid since the first cycle, this provided the opportunity to evaluate more specifically the benefit of these maintenance activities. Those streets showed less change in the average PCI. The average PCI from the first rating cycle for this area was 70.94. The average PCI calculated from the second cycle ratings is 70.04. Although these averages do not reflect any deterioration during 2007, the additional maintenance planned for the area during that time period could be expected to at least offset the deterioration and possibly increase the average slightly.
Deterioration Rate
During the initial rating cycle the deterioration rates were calculated for various street classifications and pavement types. Updated deterioration rates were calculated for the second rating cycle based on the change in PCI for each street segment from the initial rating cycle. A summary of results of the second rating cycle is shown in the table at the end of this memo. The average deterioration rate for the 25% of streets recently evaluated is compared to the average rate for the entire city as established in the first cycle. The data was analyzed and grouped by pavement type and street classification as shown. Since there were only a few arterial streets included in the evaluation, the results are reported as an overall average for all pavement types.
Unacceptable Streets
As indicated previously, the initial rating cycle determined that the PCI of 31.5% of streets fell in the unacceptable range. Taking into consideration the pavement maintenance performed to date but with the continued deterioration of other streets, it is anticipated at the end of the 2007 program 35.7% of streets will fall within the unacceptable range based on PCI.
Evaluation of Results
Results of the second rating cycle indicate that the maintenance programs are slowing or reversing the deterioration rates. The positive numbers for deterioration rates indicate the average PCI has actually increased for those specific streets. However, overall the pavement maintenance programs are not keeping up with the deterioration as evidenced by the anticipated decrease in average PCI and increase in percentage of unacceptable streets. This can be attributed to the fact that not enough of the previously identified “borderline” streets have been included in the program to slow the deterioration and prevent the PCI from declining beyond the critical point.
Continuing Improvements
The city’s asphalt pavement specification is being updated to use oils that provide an improved paving material. A higher grade of oil will be used on high-volume roads to reduce rutting, a major problem in areas of heavy truck traffic. Recycled material is being allowed but there are basic criteria it must meet in order to obtain more consistency throughout the projects. Material testing is being increased to better ensure that the pavement being placed meets the specified requirements. North Iowa between Peterson Road and West 2nd St (near Hallmark), is an example of an area where material failure is the cause of the deteriorated pavement condition. Ensuring quality material at the time of placement may have eliminated this problem.
In addition to upgraded materials, a provision is being added to the specifications to adjust payment based on the quality of the finished product. Like KDOT, the specifications will outline reductions in payments for in-place pavement densities below the specified minimum.
Microsurfacing has been added this year as another preventative maintenance tool. This process is generally intended for use on streets that are still in relatively good condition in order to prolong pavement life. If the underlying pavement is in good condition, microsurfacing can be expected to add approximately 5 years or more to the life of the pavement.
Staff members in Engineering and Street Maintenance have also been working to coordinate in-house maintenance activities with the contracted program. The intent is to make the most effective use of funds and to have a coordinated program that addresses maintenance priorities in a logical manner, whether work is performed by city or contractor forces. The program will transition over the next couple of years to a process that allows in-house crews to perform an increased portion of the patching and repairs well in advance of the contracted maintenance.
Policy Issues
As goals and expectations for the pavement maintenance program are further refined, the approach to selecting streets for maintenance and the budget request can be tailored more closely to City Commission and the public expectations for the program.
When the program was initiated, the proposed goal was to perform the work required to keep streets from deteriorating to an unacceptable pavement condition as defined by the PCI. To do that, it was projected that $17.3 million would be required for contracted maintenance in 2006 through 2008. That funding was not available, however, and the initial goal has not been met. If the expectation is that the program will meet that initial goal, or even begin to reverse the decline in overall pavement condition within a certain amount of time, significant amounts of funding will be necessary. An alternative approach is to simply do as much as possible with the available funding without focusing on the city’s overall pavement condition rating or percent of unacceptable streets.
A policy on maintenance of brick and brick composite streets needs to be finalized. Although the overall percentage of brick pavement is relatively low, the very low PCIs for those streets do have some impact on the city’s average condition ratings. At this time there is no maintenance work being performed on the brick pavements pending the policy decisions.
What else needs to be done?
Some streets simply need to be rebuilt. In the first rating cycle 31.5% of streets in the city were identified as being “unacceptable” or deteriorated beyond the point where typical preventative maintenance measures will be beneficial. Generally speaking, pavement with a PCI below 50 requires at least significant full-depth patching of the base layers and subgrade repairs if not complete removal and replacement. As part of the City’s 5-year plan, which utilizes KDOT funding, examples include Kasold north of Bob Billings Parkway (PCI 46.3 - to be reconstructed in 2009) and 19th Street between Naismith and Louisiana (PCI 31.5 - to be reconstructed in 2008). As currently structured, the pavement maintenance program is aimed at preventative maintenance and does not address such extensive rehabilitation.
Some streets with unacceptable ratings are being included in the overlay program although the poor initial condition generally results in the maintenance being a short term “band aid.” Using preventative measures on streets that are too far gone reduces the return on investment. In addition, when these relatively extensive base and subgrade repairs are made as part of the mill and overlay program, less funding is available to address streets that could better benefit from true preventative measures. As maintenance is deferred longer on the “borderline” streets the extent of required repairs will increase, essentially reducing the “bang for the buck” in the preventative maintenance program.
2007 Program
As currently proposed the 2007 program includes approximately $3.8 million for mill and overlay (including KLINK) and curb replacement, $600,000 for microsurfacing, and $300,000 for crack sealing. Of those amounts, it is estimated that at least $200,000 will be needed to patch the most deteriorated areas before resurfacing.
Conclusions
Results of the recent analysis indicate that preventative maintenance is effective where used but overall the pavement condition in the city apparently is declining. The “bad” streets are getting worse and negatively impacting the overall condition ratings. Substantial additional funding would be necessary to reverse this trend if that is the goal of the program.
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Option C |
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Funding for Streets/Curb/Ramp/Sidewalk Repairs (excludes City Personnel, equipment costs, etc.) |
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2005 (actual) |
2006 (budget) |
2007 (budget) |
2008 (proj.) |
2009 (proj.) |
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001-3000 |
General Fund |
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|||
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45-08 |
Mill & overlay |
|
575,400 |
1,300,000 |
780,000 |
1,750,000 |
|
|
45-10 |
Curb repair |
|
424,983 |
425,000 |
425,000 |
425,000 |
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|
45-14 |
Crack Seal |
|
93,750 |
500,000 |
300,000 |
300,000 |
|
|
45-02 |
Asphalt |
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98,755 |
100,000 |
120,000 |
120,000 |
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|
45-01 |
Misc. repairs |
|
58,996 |
40,000 |
55,000 |
55,000 |
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99-99 |
Contingency |
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0 |
0 |
100,000 |
100,000 |
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Sub-total |
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1,251,884 |
2,365,000 |
1,780,000 |
2,750,000 |
2,500,000 |
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214-3800 |
Gas Tax Fund |
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45-08 |
Mill & overlay |
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600,375 |
750,000 |
700,000 |
700,000 |
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45-09 |
Chip & seal |
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65,697 |
75,000 |
75,000 |
100,000 |
|
|
45-10 |
Curb repair |
|
118,665 |
165,000 |
165,000 |
175,000 |
|
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45-12 |
Sidewalk |
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0 |
25,000 |
25,000 |
25,000 |
|
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45-02 |
Asphalt |
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24,790 |
48,000 |
60,000 |
60,000 |
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45-01 |
Misc. repairs |
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49,499 |
45,000 |
60,000 |
60,000 |
|
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Sub-total |
|
859,026 |
1,108,000 |
1,085,000 |
1,120,000 |
1,200,000 |
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505-3900 |
Stormwater |
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45-10 |
Curb repair |
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121,471 |
150,000 |
140,000 |
140,000 |
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99-99 |
Contingency |
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0 |
150,000 |
175,000 |
200,000 |
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Sub-total |
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121,471 |
300,000 |
315,000 |
340,000 |
350,000 |
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301 |
Bond & Int |
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Street maint. |
(City's share) |
500,000 |
400,000 |
450,000 |
450,000 |
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(KDOT share) |
200,000 |
200,000 |
200,000 |
200,000 |
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Sub-total |
|
|
700,000 |
600,000 |
650,000 |
650,000 |
1,000,000 |
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Reserves |
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Sales Tax |
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0 |
0 |
867,000 |
850,000 |
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Cap Imp |
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0 |
502,500 |
233,000 |
0 |
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Stormwater |
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0 |
0 |
400,000 |
400,000 |
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Sub-total |
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0 |
502,500 |
1,500,000 |
1,250,000 |
0 |
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Sub-total |
Highlighted Items |
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4467500 |
4735000 |
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Highlighted figures = Funds |
Available for Contracted Maintenance |
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TOTAL |
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2,932,381 |
4,875,500 |
5,330,000 |
6,110,000 |
5,050,000 |
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Note: The plan for 2009 is to reduce funding on preventative maintenance in order to allow for |
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a focus on the "failed" streets inventory; projects to re-build the streets in this inventory will be |
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debt-financed in addition to applicable funding from KDOT. Failed streets are more likely to be |
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complete re-builds and thus more appropriate for debt financing due to their anticipated longevity |
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once re-built. |
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Summary of Deterioration Rate Analysis
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Street Classification |
Pavement Type |
Cycle 2 Avg Annual Deterioration in PCI* |
Cycle 1 Avg. Annual Deterioration in PCI |
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Arterial |
All |
-3.26 |
-5.56 |
|
Collector |
Composite (asphalt over concrete) |
1.07 |
-5.66 |
|
|
Flexible (asphalt) w/no past overlays |
-1.20 |
-2.48 |
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Flexible w/past overlays |
-0.84 |
-11.09 |
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Residential |
Composite |
0.66 |
-3.72 |
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Flexible (asphalt) w/no past overlays |
-1.17 |
-2.32 |
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Flexible w/past overlays |
4.46 |
-5.18 |
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Rigid (concrete) |
-1.10 |
-1.42 |
*Based on 2nd rating of 25% of city’s streets.