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53 Overall Findings The use of pavement management systems has been evolving as transportation agency priorities change and organizations recognize the advantages to using a systems approach to managing the pavement network. Most state departments of transportation (DOTs) have implemented pavement management systems; however, these systems are tested as agencies strive to incorporate new tech- nology into their processes, respond to the legislative requirements for reporting pavement condition data, and face increased pressure to provide transparency and accountability in agency decisions. This synthesis on the use of pavement management data serves as a timely resource for any agency interested in learning more about the ways in which pavement management data are being used to support agency decisions. The synthesis focuses on current pavement management practices in state and provincial transporta- tion agencies in an effort to determine the extent to which pavement management data are being used to support activities such as resource allocation decisions, treatment cost-effectiveness studies, and program development. A compilation of practices being used by transportation agencies is presented, primarily based on information provided from a survey that was completed by pavement management engineers in 41 state DOTs (a 79% response rate) and eight provincial ministries of transportation (MOTs) (an 80% response rate). Additional information was obtained from inter- views with representatives from five state DOTs, who had indicated through the survey that they were using their pavement management data in an innovative way. The case examples presented in chapter four illustrate how pavement management data have been used to improve data quality, evaluate the effectiveness of friction courses, expand the use of pavement management to improve safety, improve agency performance measures through the use of cost data, and establish perfor- mance measures to be used under highway concession agreements. The overall findings from this survey of practice are summarized in the following three areas: â¢ General Pavement Management Information â¢ Data Analysis and Performance Modeling â¢ Putting the Data to Work. general Pavement Management information According to the survey results, all 41 of the U.S. DOTs (100%) and seven of the eight MOTs that responded to the survey (88%) have inventory and condition information for their high-volume highway networks, including Interstate and National Highway System routes in the United States and the provin- cial highways in Canada. Fewer agencies have inventory and condition information for the lower-volume systems and there is a significant drop in the number of agencies that compile this information for front- age roads, shoulders, entrance and exit ramps, and high-occupancy lanes or bus lanes. Twenty-three of the 49 agencies (47%) are using customized proprietary pavement management software, whereas eight of 49 (16%) are using software that was developed in house. An equal number (eight of 49 or 16%) are using vendor-supplied software that has been modified in house. According to the responses provided by the nine agencies that responded by choosing the âotherâ option (18%), five reported that they have no formal pavement management software in place and four are using a vendor-supplied program that has been modified or is used in conjunction with other software programs. chapter five COnClusiOns
54 Most agencies reported that they are more likely to collect pavement distress data in at least one lane in each direction on a divided highway (44 of 49 or 90%) than on a nondivided highway (16 of 49 or 33%). On divided highways, the majority (29 of 49 agencies or 59%) collect data in one lane in only one direction. In addition to pavement condition information, the most common data in a pavement management database includes: â¢ Individual distress values (44 of 48 agencies, 92%). â¢ Traffic data (43 of 48 agencies, 90%) â¢ Composite indices (41 of 48 agencies, 85%) â¢ Individual indices (40 of 48 agencies, 83%) â¢ Treatment history (37 of 48 agencies, 77%) â¢ Treatment costs (37 of 48 agencies, 77%). Fewer than half of the agencies reported that their pavement management databases contain information on routine maintenance activities (20 of 48 or 42%), remaining service life (RSL) (15 of 48 or 31%), materials or construction information (11 of 48 or 23%), detailed performance data (six of 48 or 13%), or drainage information (one of 48 or 2%). Those agencies that use RSL in their pavement management system most often define it as the time until a condition index threshold is reached (six of 15 or 40%). An equal number of agencies (six) define RSL as either the time until the next rehabilitation or reconstruction event or the time when a pavement reaches an unacceptable condition. data analysis and Performance Modeling The survey investigated the methods used to develop pavement deterioration models and treatment rules and explored the types of analyses that are conducted with the available data. The results indicated that most agencies (33 of 48 or 69%) develop customized models developed specifically for their agency using agency data. Family models are used by 27 agencies (56%) and 23 agencies (48%) model performance indices rather than individual distresses. Only seven agencies (15%) are using probabilistic models. Five agencies (10%) report that their system does not predict pavement performance and three (6%) that they use default models. The 33 agencies that have developed customized pavement performance models were asked to identify the factors that are used in developing the models; however, only 32 agencies responded to the question. The most common variables reported included: â¢ Pavement type (30 of 32 agencies, 94%) â¢ Pavement functional condition (24 of 32 agencies, 75%) â¢ Highway system (23 of 32 agencies, 72%) â¢ Treatment history (22 of 32 agencies, 69%) â¢ Traffic data (20 of 32 agencies, 63%). Less common were variables such as maintenance history (10 of 32 or 31%), pavement structural condition (10 of 32 or 31%), climate (six of 32 or 19%), and pavement support (five of 32 or 16%). No agencies reported using environmental sustainability or safety data for developing their models. Most agencies (18 of 32 or 56%) reported that they update their models on a cycle of 3 years or more. Several agencies indicated that they update their models more frequently, with three agencies (9%) stating that they update their models every 1 to 2 years, and nine (28%) that they update them annually. Two agencies (6%) reported that they did not update their models. The treatment recommendations generated by a pavement management system may include treat- ment categories (such as preservation or rehabilitation), specific treatments (such as chip seal or overlay), or both. Sixteen of the 48 agencies that responded to this question (33%) generate treatment categories, 14 (29%) generate specific treatment recommendations, and 12 (25%) generate both. Six agencies (13%) reported that no treatment recommendations are generated by the pavement manage- ment system.
55 The most common factors used to select a feasible pavement treatment include: â¢ Pavement condition (44 of 46 agencies, 87%) â¢ Pavement type (40 of 46 agencies, 82%) â¢ Traffic volumes and/or loads (36 of 46 agencies, 78%) â¢ Pavement age (32 of 46 agencies, 70%) â¢ Highway system (29 of 46 agencies, 63%) â¢ Last treatment (27 of 46 agencies or 59%). Very few agencies reported using pavement layer characteristics (six agencies or 13%) or climatic condition (four agencies or 9%) to select treatments. Of the 46 agencies that responded to the question of whether their pavement management system includes pavement preservation treatments, 38 agencies (83%) indicated positively and eight (17%) responded negatively. Forty-six agencies that responded to the survey indicated that their pavement management system can conduct the following types of analyses: â¢ Forecast expected conditions under different funding scenarios (39 of 46 agencies, 85%) â¢ Prioritize project recommendations under constrained funding (37 of 46 agencies, 80%) â¢ Estimate funding required to achieve performance targets (37 of 46 agencies, 80%) â¢ Contribute to the development of a transportation asset management plan (34 of 46 agencies, 74%) â¢ Evaluate the cost-effectiveness of different treatments (34 of 46 agencies, 74%) â¢ Set program budget allocations (33 of 46 agencies, 72%) â¢ Allocate funding to regions based on needs (32 of 46 agencies, 70%) â¢ Set performance targets for portions of the network (32 of 46 agencies, 70%) â¢ Analyze gaps between current and desired performance (28 of 46 agencies, 61%) â¢ Prepare Highway Performance Monitoring System submittals for FHWA (22 of 49 agencies, 48%). Only 21 agencies (46%) reported that their pavement management system can be used to verify performance models using field data and four (9%) noted that the system can be used to develop contractor performance specifications and measures to monitor warranty projects. Interestingly, when agencies were asked whether their pavement management systems have been used to perform the same types of analyses, there were only three types of analyses that are done by more than half of the 49 agencies that responded to the survey: â¢ Forecast expected conditions under different funding scenarios (35 of 42 responses, 83%). â¢ Estimate funding required to achieve performance targets (31 of 42 responses, 74%). â¢ Prioritize project recommendations under constrained funding (27 of 42 responses, 64%). Fewer than half of the 49 agencies reported that they have conducted the remaining types of analyses, indicating that the traditional applications of pavement management are still the most common uses. Forty-six agencies responded to the question of whether their pavement management system includes the cost of nonpavement-related activities, such as striping or guardrail repairs. The responses were equally split, with 23 agencies (50%) indicating that their system does include those costs and 23 (50%) indicating their system does not. Putting the data to Work Pavement management data can be used in a number of different ways and the last series of ques- tions explored some of the ways it is being used. One area of interest concerned the degree to which pavement management recommendations are being applied in the field. To help quantify this metric, survey respondents were asked to estimate the percent match between pavement management
56 recommendations and projects included in the improvement programs. Eighteen of the 47 responding agencies (38%) responding to this question estimated that their pavement management recommenda- tion and funded projects match at least 70% of the time. An equal number of agencies (38%) indicated that the match exists 40 to 70% of the time. Only four agencies (9%) reported that the match exists less than 40% of the time, indicating that political influences, local conditions, insufficient funds, and district independence impact the final selection of projects. The majority of agencies responding to the survey reported that processes are in place to update historical work activities (39 of the 48 agencies or 81%), verify the quality of data collected (38 agen- cies or 79%), update pavement surface type based on work activities (35 agencies or 73%), and update the database with actual project costs (20 agencies or 42%). Only four agencies (8%) reported that they had none of the four processes in place. Pavement management systems are integrated with other databases to some degree, most com- monly with the agencyâs geographic information system (21 of 48 agencies or 44%) and the cen- tralized roadway database (13 agencies or 27%). A total of 14 agencies (29%) reported that their pavement management system operates independently. A few agencies reported that their pavement management systems are integrated with either a maintenance management system (nine agencies or 19%), a comprehensive asset management system (eight agencies or 17%), a bridge management system (seven agencies or 15%), a financial management system (six agencies or 13%), or some other type of system (six agencies or 13%). Documentation of pavement management processes and rules exist to some degree. Most com- monly, pavement condition survey procedures are documented in 38 of the 47 agencies (81%) that responded to this question. Twenty-nine agencies (62%) reported having documentation in place for their treatment rules and 27 agencies (57%) document their performance model equations. Pavement management roles and responsibilities are documented in 17 agencies (36%) and quality assurance procedures (such as those required under MAP-21) are documented in 17 agencies (36%). A variety of different types of pavement management data is shared with various stakeholder groups. Most often shared with elected and appointed officials is information about current and fore- casted pavement conditions as well as future funding needs. Agency decision makers are provided the same information, but also tend to receive information on candidate and funded projects as well as expected future funding levels. Other external stakeholders are commonly provided information on current pavement conditions, but some agencies report providing information on forecasted con- dition, funded projects, and future funding needs. In the United States, the following types of pavement management enhancements have been made or will be made in the next 2 years by DOTs: â¢ Data quality management procedures have been developed in 20 of the 41 agencies (49%) that responded to the question. An additional 26 agencies (63%) will be making these enhancements within the next 2 years. â¢ Twenty agencies (49%) reported that their software has been updated and 25 (61%) that the software will be updated within the next 2 years. â¢ The majority of state DOTs (29 agencies or 71%) reported that they have changed their pavement condition survey methodology to include continuous surveys rather than use a sampling approach and six additional agencies (15%) intend to make that change within the next 2 years. â¢ Twenty-four agencies (59%) reported that they have changed from manual to automated sur- veys and 12 additional agencies (29%) intend to make the change within the next 2 years. â¢ As part of the automated surveys, 18 agencies (44%) stated that they have migrated to a three- dimensional data collection system and 17 additional agencies (41%) intend to make that shift soon. â¢ Twenty-seven agencies (66%) reported that they have incorporated pavement preservation treatments into their pavement management system and 11 more agencies (27%) that they will be adding these treatments within the next 2 years.
57 â¢ A significant number of agencies (22 or 54%) also reported that they are using their pavement management system to optimize resource allocations and 15 additional agencies (37%) plan to use their system in that way soon. â¢ Twenty-one agencies (51%) noted that they plan to be able to analyze investment needs across asset types within the next 2 years and 15 (37%) that they plan to incorporate risk into investment decisions. â¢ Eight agencies (20%) noted that they collect network-level pavement structural condition data and nine additional agencies (22%) that they plan to collect the data within the next 2 years. The same types of enhancements are planned in the Canadian MOTs; however, there are a significant number of agencies that indicated they intend to increase the frequency of their surveys. Seven of the eight agencies (88%) have completed this change and one agency (12%) plans to make the change within 2 years. Two agencies (25%) reported that they collect network-level pavement structural condition data and four more (50%) that they plan to conduct the surveys within the next 2 years. Pavement structural condition was also mentioned by six of the 16 agencies (38%) that responded to the question asking what additional data they would like to collect in their pavement manage- ment system. Other respondents mentioned that they would like to have pavement surface texture or friction data (three agencies or 19%), pavement layer and material data (six agencies or 38%), and automated cracking data (three agencies or 19%). suggestiOns FOr Further researCh The following suggestions for further research are made based on the results of the literature review and the survey conducted in the development of this synthesis: â¢ The development of guidelines for analyzing risk, optimizing the use of available funding, setting performance targets, allocating budgets, and evaluating network-level structural condition to support the broader consideration of these factors in pavement management. Improved information on pavement structure and materials data to support their pavement man- agement analyses would be helpful to pavement management practitioners. The survey responses noted that data are largely available on the Interstate and National Highway System, but less so on the remainder of the system. Network-level structural condition surveys and stronger links to construction and materials databases were identified by several respondents as desired data. In addition, the survey results indicated that pavement management is largely being used to demonstrate the impacts on network conditions associated with different funding levels, estimate funding needed to achieve performance targets, and prioritize recommendations under constrained funding. However, fewer than 20 of the 41 state DOTs and only four of the seven Canadian MOTs that responded to the survey are using their pavement management sys- tems for other types of analyses, including setting performance targets and evaluating the cost-effectiveness of investment spending, even though their software provides these capabili- ties. In terms of enhancements, 21 agencies indicated interest in enhancing their ability to analyze investments across asset types in the next 2 years and 15 agencies expressed interest in incorpo- rating risk into their investment decisions during that timeframe. â¢ The development of a framework for using pavement management data to support the whole-life costing analysis and other capabilities required for the development of a Trans- portation Asset Management Plan (TAMP). There are still several states that do not have pavement management software that will satisfy the minimum requirements outlined in the Notice of Proposed Rule Making for developing a TAMP. The development of a framework for using pavement management data to support the development of a TAMP, including the conduct of a whole-life cost analysis, would allow agencies to use their pavement management data to better evaluate the long-term cost-effectiveness of different investment strategies and more fully support their agencyâs asset management efforts. â¢ The development of electronic templates that practitioners could use to document pave- ment management treatment rules, performance models, roles, and responsibilities. A number of agencies document their pavement condition survey procedures, their treatment
58 rules, and their performance models; however, there is less evidence that documentation exists for data quality procedures or pavement management roles and responsibilities. The absence of this type of documentation leaves an agency at risk if pavement management personnel retire or change positions. The development of electronic templates would simplify and standardize the documentation process for practitioners. â¢ The conduct of technology transfer and outreach activities that showcase best practices in pavement management and highlight the use of pavement management data for non- traditional uses. As noted earlier, pavement management systems are not being fully utilized at the present time. In addition, the results indicate that pavement management systems are not largely integrated with other management systems and databases, which could limit the feasibility of using pavement management data for nontraditional purposes. The conduct of technology transfer and outreach activities (such as training courses, web conferences, and peer exchanges) provide an opportunity for practitioners to learn strategies for improving practices from their peers. â¢ The establishment of guidelines for mining pavement management data so that it can be used in developing performance measures for warranty contracts and other types of publicâprivate partnerships. The results of the survey indicate that only two agencies are using pavement management data to develop performance measures for warranty contracts and other publicâprivate partnerships. As this contracting method becomes more common in the United States, transportation agencies will benefit from the availability of guidance on using pavement management data to establish effective performance measures to monitor contractor performance.