Anwaar Ahmed

Aggregate and disaggregate statistical evaluation of the performance-based effectiveness of long-term pavement performance specific pavement study-5 (LTPP SPS-5) flexible pavement rehabilitation treatments

Engineers continually seek effective techniques for preserving highway infrastructure. Using data from the specific pavement study#5 of the long-term pavement performance (LTPP) programmes western region, this article evaluated the performance of eight flexible pavement rehabilitation treatments. Aggregate and disaggregate post-treatment performance models were developed for each treatment. Effectiveness was measured in the short term (roughness reduction) and long term (estimated treatment service life and area bounded by the performance curve (ABP)). The results showed that compared to 2-inch treatments, 5-inch treatments were on average more effective in terms of the following measures: 47% (estimated service life) and 35% (ABP) depending on the level of surface preparation, mix type and initial pavement condition. Also, relative to minimal surface preparation, intensive surface preparation generally yielded greater effectiveness: 25% (estimated service life) and 49% (ABP) depending on added thickness, mix type and initial pavement condition. Compared to recycled mix treatments, virgin mix was marginally more effective. Finally, compared to pavements treated in poor condition, those treated in good condition were significantly more effective. Treatment effectiveness models were developed for predicting the expected effectiveness of future treatments on the basis of attributes such as treatment type, added layer thickness, level of surface preparation and mix type.

A Hybrid Pareto Frontier Generation Method for Trade-Off Analysis in Transportation Asset Management

Trade-off analysis, one of the key elements of transportation asset management (TAM), helps decision makers to not only quantify how different resource allocations affect system performance but also investigate the trade-off relationships between cost and performance measures and between different performance measures. In the fast-growing field of TAM, researchers are beginning to quantify the trade-offs among the performance measures. A successful quantification of these trade-offs is important for the practice because the highway agency decision makers responsible for project selection have long been stymied by a lack of knowledge of the extent to which different decisions lead to different performance trade-offs. In a follow-up to recent research efforts that have sought to address this issue, this article presents a further improved methodology to facilitate the analysis of trade-offs in TAM. First, a general multiobjective optimization framework for TAM is established. Next, the developed hybrid method is presented, which is then shown to quicken the generation of Pareto frontiers for the purpose of conducting trade-off analysis. Using a case study, the proposed hybrid method, which was implemented on a computer to generate Pareto frontiers, ultimately converged faster and generated better-distributed Pareto frontiers compared to the NSGA II method of Pareto frontier generation in the TAM context. Using the generated Pareto frontiers, trade-off analysis between cost and performance measures and between performance measures are demonstrated in this article.

Multidimensional benefit–cost evaluation of asphaltic concrete overlays of rigid pavements

Using the data from a national study in the USA, this study demonstrated a comprehensive and multidimensional pavement treatment evaluation methodology and used the methodology to evaluate the short-term and life cycle cost-effectiveness (CE) of five rigid pavement rehabilitation treatments. Four measures of effectiveness were used in this study: the sudden decrease in surface roughness, treatment service life, increase in average pavement condition over the service life and the area bounded by the performance curve. This study established relationships that quantify the influence of pre-treatment condition on treatment effectiveness. Also, the models were developed to describe the treatment effectiveness as a function of traffic loading and climatic severity. It is seen that at high traffic loading, there is relatively little difference in treatment effectiveness across various climate severities. This study suggests that superior effectiveness of a treatment does not necessarily translate into superior CE. Also, the treatment location was found to influence the relative effectiveness of the treatments. Overall, the results suggest that treatment ‘crack-and-seat and 8-in. asphalt concrete overlay’ is the most cost-effective.

A Synthesis of Overweight Truck Permitting

For purposes of safety and system preservation, trucking operational characteristics are regulated through legislation and policies. However, special permits are granted for trucks to exceed specified operational restrictions. Thus, the Indiana DOT not only seeks highway operations policies that retain/attract heavy industry including those that haul large loads but also seeks to protect the billions of taxpayer dollars invested in highway infrastructure. As such, it is sought to avoid policies that may lead to premature and accelerated deterioration of assets through excess loading or undue safety hazard through oversize loads. This study was carried out primarily to document the state of practice of truck weight permitting in Indiana vis-a-vis those of its neighboring states. This was done on the basis of the fee amounts, fee structure, and the ease of the permit acquisition process for the permit applicant. The study determined that while the upper thresholds (dimensions and weights) for legal trucking operations are generally the same across states, those for extra-legal operations vary considerably. Also, findings from published literature, agency websites, and phone interviews showed that there is great variability in overweight and oversize truck permitting criteria across the states. Furthermore, it was seen that no state has adopted explicitly the weight-distance concept for its overweight trucks. However, in the states of Indiana, Ohio, and Illinois, the fee structures for overweight vehicles include weight levels and extents of travel, and thus operate in a manner similar to a weight-distance fee. From the perspective of overweight and oversize thresholds and associated permit fees, it was observed that a number of states such as Indiana appear to be generally more favorable to trucking because they have relatively higher upper thresholds for defining an overweight truck and/or relatively lower fees for overweight trucking operations. However, as demonstrated in the excel spreadsheet case studies that accompany this report, the differences in fees incurred by truckers across the states are significantly influenced by a variety of factors including the trip circumstances, permitting criteria, and trip frequency and distance. This report also documents the streams of revenue from the permits issued for extra-legal trucking operations over the recent past: approximately

Estimating national road crash fatalities using aggregate data

12 million annually. On the subject of revenue neutrality, the study reports that highway agencies that had switched from a single-trip permit system to an annual flat fee permit system report that they benefited from cost savings due to reduced monitoring efforts of truck trips but had lost significant revenue overall. Using data from a national study, the report quantifies the extent to which each additional payload increases pavement deterioration. The data also suggests that having more axles on a truck reduces pavement deterioration and consequently, damage repair cost, but could decrease the revenue to be derived from overweight permitting. In conclusion, the study recommended the conduction of a cost allocation study to update these load-damage relationships as well as the overweight permit fee structures, to reflect current conditions in Indiana.

Scale and Condition Economies in Asset Preservation Cost Functions: Case Study Involving Flexible Pavement Treatments

Injuries and fatalities from road traffic crashes have emerged a major public health challenge in Pakistan. Reliable estimates of road crash fatalities (RCF) of a country, is a vital element needed for identification and control of key risk factors, road-safety improvement efforts and prioritizing national health. Reliability of current annual RCF estimates for Pakistan becomes highly questionable due to serious underreporting. This study aimed to predict annual RCF for Pakistan using data from World Health Organization and International Road Federation sources. An ordinary least square (OLS) regression model that relates fatality rate with different explanatory variables was developed. RCF were predicted for Pakistan for year 2012 and 2013, and results were compared with national police reported estimates. Study results indicated that there is serious underreporting of RCF in Pakistan and immediate measures are needed to improve the existing road crash recording and reporting system at the national and subnational levels.

Performance Evaluation and Life Prediction of Highway Concrete Bridge Superstructure across Design Types

Estimates of planning-level treatment costs are vital inputs for preservation project budgeting, prioritization, and programming in highway asset management. However, with the paucity of analytical research on highway asset preservation costing, agencies have resorted to the use of average costs. However, average cost values fail to adequately accommodate the influence of cost factors such as project size and asset condition at the time of the preservation treatment. In addressing this issue, this paper explores the efficacy of different mathematical specifications, including the Cobb-Douglas form and a variety of other nonlinear forms, for developing treatment cost functions. The paper shows how flexible formulations could be used to specify the response variable in order to avoid unduly restricting the models and to yield cost estimates that are more reliable compared to average costs. The paper shows how to investigate the direction and strengths of scale economies and condition economies in highway asset preservation costs using mathematical forms that allow for determining the partial derivatives of treatment cost with respect to asset dimensions and pretreatment condition. The paper demonstrates its concepts by using data on flexible pavement preservation treatments at a midwestern state highway agency.

Estimating the marginal cost of pavement damage by highway users on the basis of practical schedules for pavement maintenance, rehabilitation and reconstruction

AbstractManagers of highway bridge infrastructure constantly seek to improve their predictions of the physical performance of their facilities at any future time and also to identify the influentia...

A framework for assessing the consequences of deferred or hastened highway asset interventions

Highway agencies worldwide strive to ensure that highway users pay fees that not only recover the costs of pavement damage but also are equitable. In addressing the limitations of past research and quantifying the resulting adverse consequences on their analysis outcomes, this paper presents a comprehensive framework to derive more representative estimates of pavement damage cost. The developed framework incorporates practical pavement repair schedules that include all the key repair categories as a basis for estimating the marginal pavement damage cost (MPDC). The framework was applied to pavements of different surface type, functional class and age. On average, the MPDC was found to range from

Pavement Repair Marginal Costs: Accounting for Heterogeneity Using Random-Parameters Regression

0.0032 per ESAL-mile on Interstate highways to