Highway Maintenance Quality Assurance Final Report (1997) / Chapter Skim
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4 Development of Prototype QA Program
4 Development of Prototype QA Program
Pages 59-88
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From page 59... ...
The prototype program began as a collection of sound maintenance management and maintenance quality practices, most of which formed We core of Me program. Although the ideas and procedures behind some of these practices were modified to better capture today's quality management precepts, over practices were readily acceptable for inclusion as part of the prototype QA program.
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From page 60... ...
These program goals included We following: Functional in a centralized or decentralized management environment and In both large and small agencies. · Produces LOS ratings regardless of Me level of contract maintenance.
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From page 61... ...
· Key Maintenance Activities~roup~ng of key work activities into like categories (i.e., maintenance elements) for Me purpose of evaluating maintenance quality.
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From page 62... ...
Prototype QA program flow chart. 62 target LOS's)
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From page 63... ...
-Application of Me activity cost data and field trial results toward deterrnin~ng Me costs required to produce a specific TWOS established from customer expectation input. Formal LOS Inspections, Analysis, and Reporting Periodic maintenance ratings stemming from random inspections of short segments of the entire highway system maintained by an agency.
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From page 64... ...
During Me August 1995 field reviews of Me seven selected highway maintenance agencies, none of Me agencies indicated incorporating data from other management information systems into Weir LOS rating process. The general sense among Me agencies was Cat data interchange was too difficult or inefficient, or Cat the data contained in the over systems were not acceptable for use.
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From page 65... ...
Because pavement maintenance actions provide little or no structural improvement, deflection data were not considered to be suitable for use as Indicators of maintenance quality. Pavement friction Is a safety-related condition measure that describes Me slipperiness of a pavement surface.
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From page 66... ...
The suitability of PMS distress data for use In He LOS rating system was found to be dependent on many factors, the foremost of which include He following: Frequency of pavement surveys Most PMS's entail annual (100 percent of pavement sections sampled each year) , biennial (100 percent of pavement sections sampled every 2 years)
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From page 67... ...
Accuracy of data and type of pavement surveys PMS distress data are collected In a myriad of fashions, ranging from visual surveys of randomly selected samples to automated continuous surveys. For PMS data to be useful In He LOS ratings, He information must be collected from He same sample units as He LOS ratings and the condition surveys must be objective, accurate, and repeatable.
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From page 68... ...
A Borough and welldocumented inspection is essential for making informed and practical recommendations to correct bridge deficiencies. A well-prepared bridge inspection report not only provides information on existing bridge conditions, but it also serves as an excellent reference source for future inspections.
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From page 70... ...
Because maintenance quality should at least be evaluated annually, BMS data based on biennial surveys would not be adequate. Timing of bridge Inspections Bridge surveys are often performed at times of the year when weaker conditions are more moderate, and depending on workload, some may be performed by one or more qualified bridge inspection consulting firms.
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From page 71... ...
Infrastructure Management Systems An IMS is an overall management system Hat integrates all He many different infrastructure components and individual management systems of an agency. It is a tool Hat provides highway and public works managers win He information necessary to make important decisions about total infrastructure maintenance, renovation, and replacement.
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From page 72... ...
A review of various papers and articles on IMS's resulted in Me identification of several maintenance-related features Cat comprise an IMS database. Listed in table 11 are Me drainage, traffic control and safety (signs and barriers)
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From page 73... ...
In an IMS, just as in other management systems, most condition surveys are not performed with Me frequency recommended for a QA program, are not conducted at Me same locations as Me LOS sample sections, and may not contain the exact items needed to perform We LOS ratings. Avoiding Bias in Data Collection and Analysis The quality and efficiency of highway maintenance management Is greatly Improved Trough the collection of accurate data and Trough Me use of unbiased sampling and analysis techniques.
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From page 74... ...
~ developing the prototype program, serious consideration was given to ways of minim~z~g bias in Me collection and analysis of LOS rating data, as wed as customer input data. With regard to Me former type of data, a roadway segment sampling procedure was developed Mat would enable agencies to achieve a desired level of precision in LOS ratings for each maintenance stratum of interest.
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From page 75... ...
Discussions of the statistical applications in each area are provided In We sections below. Customer Surveys ~, To obtain as unbiased customer input as possible concenung the expectations of and satisfaction with highway maintenance LOS, a sound survey sampling process was developed and made part of Me prototype QA program.
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From page 76... ...
z = z-statistic, standard normal variate associated win a particular confidence coefficient (for 95 percent confidence, z=~.96~. This formula is based on random sampling win replacement of samples after each survey.
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From page 77... ...
The systems In place at Florida, Maryland, and British Columbia were clearly attribute-based, why individual maintenance features/characteristics evaluated against a specified standard and given corresponding pass or fad! ratings (in the case of British Columbia, Good, Fair, and Nof-to-Standard ratings are Event.
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From page 78... ...
The details of this computational approach are given in the following section titled "LOS Analysis." a A third consideration of statistics In LOS field inspections pertained to He need for a pilot field study, or a trial run of LOS inspections. A pilot study provides insight about the inherent variability of LOS ratings, which can then be taken into consideration when determining He required sample size for (future)
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From page 79... ...
The method recommended in Me prototype QA program for selecting roadway sample segments was simple random sampling, performable through a random number generator function available In most statistical or spreadsheet computer software. This method assures each individual segment In Me total roadway population Me same chance of being chosen for field inspection.
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From page 80... ...
s2 where: s2 = sample variance of segment LOS ratings. LOSsi = individual segment LOS values for n sample segments.
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From page 81... ...
A cannon set of randomly selected roadway segments are independently inspected at Me same time by bow Me central-office team and Me satellite team. The paired ratings from all sample segments are Men statistically analyzed via Me z-test In order to determine if Me satellite team's ratings are significantly different from the central-office team's ratings.
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From page 82... ...
-a r Table 12 highlights some of He important facets of two recent customer surveys, One conducted by the Minnesota DOT to determine both customer expectations and customer satisfaction and He over conducted by He Pennsylvania DOT to deter~rune customer expectations. This information reveals much about He resources required to obtain reliable customer input.
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From page 83... ...
Pennsylvania conducted a customer satisfaction survey shortly after Me customer expectations survey. The back-to-back surveys were conducted over a Month timeframe at a reported combined cost of $40,000.
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From page 84... ...
In the design of maintenance questionnaires, it was determined Cat Me most appropriate way to measure Me importance of or satisfaction win various maintenance work items Is to use rating scale questions. Scales of 1-5, I-10, and I-100, win ~ representing "not Important" and 5, 10, or 100 representing "very unportant," are effective means of measuring customer expectations and satisfaction, particularly when Me questions are posed in simple terms to which Me customer can relate (e.g., potholes, smoothness, visibility)
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From page 85... ...
Without He QC function being performed throughout He implementation process, He ratings Hat are produced will most likely be challenged. To prevent major issues being made of LOS ratings, formal LOS training and a pilot field study were made major components of He QA program.
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From page 86... ...
Although variability must be expected among the LOS ratings, it is important to minimize it to acceptable limits and then document it for later use in determiriing the required sample size for formal LOS field inspections. The objective of Me LOS training component is to make sure that raters look at the same features In each case and arrive at He same basic conclusions concerning Weir evaluations.
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From page 87... ...
Ability to produce budget requests showing He e~asJdug LOS, He proposed/desired LOS, and the funding required to achieve and maintain the desired LOS. Ability to measure customer satisfaction win He LOS being provided.
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