Highway Maintenance Quality Assurance Final Report (1997) / Chapter Skim
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5 Investigation of Highway Maintenance QA and Long-Term Performance of Highway Facilities
5 Investigation of Highway Maintenance QA and Long-Term Performance of Highway Facilities
Pages 89-116
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From page 89... ...
In over words, Heir desire is for a QA program that has He dual effect of ensuring quality to He traveling public (~rough safe, comfortable, and visually pleasing roadway facilities) and to He highway agency (through longer lasting and more cost~ffective roadway facilities)
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From page 90... ...
Several tracking methods were examined and are briefly described In We section below, titled "Work Approach." Two methods were considered to have We most potential for relating maintenance quality and facility performance and were, therefore, evaluated in greater detail using actual maintenance LOS rating data and highway performance data collected from two States. These two methods are formally presented in We QA program Implementation Manual, but We results of We detailed evaluations regarding their effectiveness and usefulness are provided In this chapter.
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From page 91... ...
InJeX. This method is a relatively simple procedure Mat allows an agency to make yearly comparisons of its LOS ratings and Me associated maintenance costs.
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From page 92... ...
Because higher LOS ratings signify more effective and efficient maintenance, it is logical Mat an increase in pavement LOS should be accompanied by a reduction in the pavement deterioration rate (i.e., Increased pavement performance) , all over factors being equal.
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From page 93... ...
With deduct values established for multiple years, Me annual pavement LOS ratings for the corresponding years are linked together, so Cat Me resulting trend between pavement maintenance quality and pavement performance can be examined. Figure 9 provides a simple illustration of this concept using performance curves associated win two levels of routine maintenance good and poor.
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From page 94... ...
(2) Pavement Performance Deduct Curve Win Poor Routine Maintenance.
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From page 95... ...
At some point along the LOS rating scale, Me rate of reduction in the Acondition index will decrease win an increase in LOS rating. Hence, a plot of Acondition index versus LOS for a range of LOS ratings may allow an agency to select Me LOS raking that bow meets the desired LOS and optimizes pavement performance.
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From page 96... ...
Conceptual illustration of pavement condition-LOS rating relationship.
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From page 97... ...
U 50P~ o / - x x x x x x x x x ~x x x x x ~x x x x x x ~v Y ~ A V V v A A ~SC X ~X X X X °A' X X X X OLOS Rahng 100 Figure 13. Conceptual illustration of variability ~n condition-LOS rating relationship.
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From page 98... ...
Preliminary Assessment of Tracking Methods Many factors were taken into consideration when determining Me worthiness of Me six me~ods for tracking Me relationship between maintenance LOS ratings and Me Tong-term performance of highway features. Key factors in this initial evaluation Included Me complexity of Me memos, the availability of required data, and Me associatecl confounding variables (e.g., traffic, climate, design, rehabilitation)
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From page 99... ...
Table 13. Regression mode!
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From page 100... ...
The main disadvantage of Me Backlog Analysis method is Mat backlog measurements are substantially impacted by Me respective maintenance and rehabilitation budgets, as wed as design, traffic, and over factors. Thus, interpretation of the overall results Is somewhat subjective and must be done very carefully.
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From page 101... ...
LOS relationships Bat are developed can be used by over groups within an agency to accurately project pavement performance based on a prescribed level of maintenance. The condition indicator vs.
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From page 102... ...
Table 14 matches He different agency types with the most appropriate of He six tracking methods. Selection of Methods for Detailed Evaluation Based on He summarized advantages and disadvantages and He matching of He methods with the appropriate agency types, two of the SIX tracing methods-Backlog Analysis and Change in Condition Indicator vs.
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From page 103... ...
The LOS data were obtained from Me Florida MRP database and consisted of annual roadway element LOS ratings for District 3 highways for fiscal years 1990-91 Trough 1995-96. During the evaluation process, two separate comparisons of maintenance quality and pavement performance trends were conducted.
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From page 104... ...
Flonda has defined its backlog as pavement sections win any of the three condition indicators (crack, nde, or ruffling) having a value of 6 or less.
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From page 105... ...
Very Good 3.099 0.000 3.099 0.000 0.000 Good 147.043 15.917 45.520 62.903 12.747 Fair 96.590 0.000 13.127 50.840 32.623 Poor 23.904 0.000 0.000 2.569 10.688 Very Poor 77.993 0.000 0.000 0.000 1.648 L Total 1 348.6291 15.9171 61.7461 116.3121 57.7061 86.992 ~ _ 0.000 0.000 0.000 Rehabilitated ' 0-000 9.956 0.000 10.647 76.345 Table 17. 1995 pavement condition range matrix`.
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From page 106... ...
Average LOS ratings by year.
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From page 107... ...
Probability plot for pavements win a previous condition of Good.
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From page 108... ...
Probability plot for pavements wi~ a previous condition of Poor.
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From page 109... ...
- This figure shows Cat Me 1995-96 pavements are actually increasing in condition, whereas the 1991-92 pavements are remaining We same. Although logic and experience tell us Cat pavements do not Increase In condition win dine, proactive maintenance practices can have a positive effect on certain pavement management condition indicators In the higher pavement condition categories.
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From page 110... ...
of He 1995-96 pavements were rehabilitated, He pavements win He higher LOS rating have a higher probability of remaining In He same category and not deteriorating to a lower category, even if ah of He rehabilitated pavements fell to He Very Poor category. However, just like He Fair category, the only way to make a complete and accurate comparison would be to know He actual condition of the rehabilitated pavements prior to He application of He rehabilitation activity.
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From page 111... ...
By selecting non-consecutive years, no consideration was given to He level of maintenance during He years between 1991 and 1995. To asses He Hue accuracy of He backlog analysis, a year-to-year review of the LOS ratings should be performed and incorporated into He results.
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From page 112... ...
The pavement condition data were downloaded from Me Iowa EMS database and included annual PCI ratings and surface roughness measurements for all interstate and primary route pavement sections for Me years 1988 through 1993. The LOS data were obtained from Me 1993 maintenance quality evaluation report (Iowa DOT, 1993)
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From page 113... ...
Figure 19 contains the resulting plots of LOS ratings and yearly deduct values vs. time for Me Iowa highway sections.
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From page 114... ...
Plot of LOS rating and PCI deduct values vs. time for Iowa Interstate and primary roads, ad pavement herpes.
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From page 115... ...
Interpretation, Appraisal, and Applications Presented in this chapter were sac possible me~ods for tracking the relationship between maintenance LOS and the long-term performance of highway facilities. Two of these six me~ods, Me Backlog Analysis memos and the Change in Condition Indicator vs.
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From page 116... ...
Interested agencies must be advised to recogruze me differences between Me purposes for and Me inferences to be derived from information collected for PMS and LOS rating systems. These differences are as follows: · PMS data generally tends to quantify the remaining life of specific pavement sections or projects.
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