Lynne Cowe Falls

Incorporating Road Safety into Pavement Management

Improving road safety through proper pavement engineering and maintenance should be one of the major objectives of pavement management systems. When pavements are evaluated in terms of safety, a number of factors related to pavement engineering properties are raised, such as pavement geometric design, paving materials and mix design, pavement surface properties, shoulder type, and pavement color and visibility. Each year there are voluminous annual reports on traffic accident statistics and discussions of such road safety issues as road safety modeling and pavement safety measurements and criteria. Although road safety may be considered a separate area, it should be incorporated into pavement management systems. The main pavement engineering relationships associated with road safety are identified, and the various aspects of road safety related to pavement management, such as pavement types, pavement surface macrotexture and microtexture, and pavement safety measurements, criteria, and evaluation methods, are discussed. A systematic approach is proposed for the coordination of pavement maintenance programs with road safety improvement and the incorporation or integration of safety management with pavement and other management systems. Finally, a list of possible remedial measures for road safety improvements associated with pavement maintenance activities is recommended.

Determining Return on Long-Life Pavement Investments

It is becoming increasingly necessary in life-cycle analysis (LCA) of infrastructure assets, including pavements, to take a longer-term approach than has been used, mainly to ensure sustainability and assess the impacts of todays decisions accurately. LCA can include primarily life-cycle cost analysis (LCCA), but it also can include considerations of resource conservation, environmental impacts, energy balance, and so forth, and it can involve short-, medium-, and long-term periods. It is thus possible to develop a context for LCA of likely and uncertain societal activities, including transportation, over these periods. Conventional LCCA is directed toward comparing competing alternative investment strategies and can involve a range of stakeholders. Of the methods available, present worth of costs is almost exclusively used in the pavement field. However, when medium- to longer-term life-cycle periods are involved, rate-of-return and cost-effectiveness formulations can be applicable. A numerical example ...

Analyzing Longitudinal Data to Demonstrate the Costs and Benefits of Pavement Management

Roads and highways generally represent the single largest asset value of public infrastructure. Preservation of this asset value through timely and cost-effective maintenance and rehabilitation presents an enormous financial, management, and technical challenge to public agencies. Until recently, agencies have relied on designated or “silo” systems for pavement, bridge, and other management systems; which shared common elements of data collection, analysis, and reporting. Successful implementation of asset management requires a methodology for trade-off analysis between competing silos at the strategic level. Ultimately, many agencies may need to significantly change their business decision-making process, potentially resulting in the costs of implementation outweighing the benefits. This article describes frameworks for using longitudinal data to conduct a cost-benefit analysis of management system implementation. It also demonstrates how the same data can be used to improve technical models, thereby producing immediate benefits to the agency through enhanced decision making and, ultimately, reduced costs.

ASSET MANAGEMENT AND PAVEMENT MANAGEMENT: USING COMMON ELEMENTS TO MAXIMIZE OVERALL BENEFITS

The public and private sectors have been managing their assets in some form for many years. Recently, however, the concept of asset management has been formulated to draw more explicitly on the principles of business, technology, economics, and other disciplines in a systematic and integrated way. This strategy offers cost-effective and responsive advantages in managing the public’s assets. Other management systems, particularly pavement management, have preceded the current interest in asset management by several decades. Accordingly, it is useful to assess whether there are common elements between asset management and pavement management and, if so, whether the experience gained from pavement management implementation and operation can be of benefit. In a generic sense, asset management has extensive commonalities with its component systems such as pavement management. However, asset management has some issues to resolve in progressing from a framework to an operational reality. A number of ways or areas in which asset management system development and implementation can benefit from pavement management operational experience are presented. Finally, some technical, economic/technical, and institution and user opportunities for innovations and advancements in asset management systems are identified.

Pavement Performance Evaluation of Three Canadian Low-Volume Test Roads

New and improved pavement technologies are developed through laboratory investigations, construction and maintenance, theoretical analyses, long-term performance studies such as the Strategic Highway Research Program (SHRP) and the Canadian SHRP, and integrated programs of laboratory and field research. The latter, integrated approach is the subject of this study. Although various test roads have been placed in Canada over the past several decades, this study focuses on three test roads that examine low-volume road performance. These test roads are located in Ontario, Quebec, and Alberta and are being monitored by three Canadian universities. The background, test road objectives and location, design of the test roads and instrumentation, construction, and vehicle testing are first summarized briefly. Then, some ongoing projects at the three test roads and how results from the three test roads can be used either individually or collectively to improve current practices within Canada are discussed, with a focus on low-volume road technologies. Particular emphasis is placed on the performance of low-volume resource roads with respect to both traffic loading and environmental conditions. Findings from these studies will also be useful in the Canadian national calibration of the new Mechanistic–Empirical Pavement Design Guide.

Cohen's Weighted Kappa Statistic in Quality Control-Quality Assurance Procedures: Application to Network-Level Contract Pavement Surface Condition Surveys in British Columbia, Canada

Like many provincial and municipal agencies, the British Columbia Ministry of Transportation (BCMoT) contracts out the collection of pavement surface condition data. Because BCMoT is committed to contracts with multiple private contractors, quality assurance (QA) plays a critical role in ensuring that the data are collected accurately and repeatably from year to year. Comprehensive QA testing procedures for surface distress data have been developed and implemented since the data collection has been based on visual ratings with event boards. Control sites that are manually surveyed are used to evaluate whether the contractor is correctly applying the BCMoT pavement surface distress rating system. To date, the QA testing has been based on a composite-index–based criterion for assessing the level of agreement and supplemented with the detailed severity and density rating data. However, the use of a composite index presents some limitations related to the model formulation and weightings assigned to particular distress types. Although the detailed ratings are useful as a diagnostic tool to pinpoint discrepancies, in the disaggregated format, they are not conducive as acceptance criteria for QA testing. Not widely used in the field of engineering, Cohen’s weighted kappa statistic has been applied since the 1960s in other areas to assess the level of agreement beyond chance among raters. The statistic was therefore identified as a possible solution for improving the ministry’s QA surface distress testing process by providing an overall measure of the level of agreement between the detailed manual benchmark survey and the contractor severity and density ratings. The application is described of Cohen’s weighted kappa statistic for visual surface distress survey QA testing using the BCMoT survey and testing procedures as a case study.

Pavement Asset Management: Haas/Pavement

This book presents the current methodologies and practical applications of managing pavements. The book contains seven parts that include : Part I: The Evolution of Pavement Management; Part II: Data Requirements; Part III: Determining Present and Future Needs and Priority Programming of Rehabilitation and Maintenance; Part IV: Structural Design and Economic Analysis: Project Level; Part V: Implementation of Pavement Management Systems; Part VI: Examples of Working Systems; and Part VII: Looking Ahead. The chapters are: Introduction; Birth and Teen Years of Pavement Management; Pavement Management Development from 2010; Setting the Stage; Overview of Pavement Management Data Needs; Inventory Data Needs; Characterizing Pavement Performance; Evaluation of Pavement Structural Capacity; Evaluation of Pavement Surface Distress Condition Surveys; Evaluation of Pavement Safety; Combined Measures of Pavement Quality; Data Base Management; Communicating the Present Status of Pavement Networks; Establishing Criteria; Prediction Models for Pavement Deterioration; Determining Needs; Rehabilitation and Maintenance Alternatives; Priority Programming of Rehabilitation and Maintenance; Developing Combined Programs of Maintenance and Rehabilitation; A Framework for Pavement Design; The Mechanistic-Empirical Pavement Design Guide (MEPDG) Process for Pavement Design; The MEPDG for Design of New and Reconstructed Rigid Pavements; Rehabilitation of Existing Pavements; MEPDG in Practice; Economic Evaluation of Alternative Pavement Design Strategies and Selection of an Optimal Strategy; Steps and Key Components of Implementation; Role of Construction; Role of Maintenance; Research Management; Basic Features of Working Systems; Network Level Examples of Pavement Management; Project Level Examples of PMS Software; Highway Design Manual-4 (HDM-4) the Upgraded World Bank Model; City and County Pavement Management Systems; Airport Pavement Management; Analyzing Special Problems; Applications of Expert Systems Technology; New and Emerging Technologies; Institutional Issues and Barriers Related to Pavement Management Implementation; Cost and Benefits of Pavement Management; Future Direction and Need for Innovation in Pavement Management; and Developments in Asset Management.

Effects of pavement condition on roadway safety in the province of Alberta

ABSTRACT The mission of every highway agency in many parts of the world is to provide safe, reliable, and economic road network. Many highway agencies such as Alberta Ministry of Transportation usually evaluate road safety by the number of collisions and assess the reliability of roads using a performance index called International Roughness Index (IRI). This research aimed at modeling the relationship between pavement condition and number of collisions in the province of Alberta, Canada. All rural highways in Alberta were considered. Zero inflated Poisson (ZIP) and NB regression were used to estimate the relationship between the number of collisions and the road IRI value and rut depth. Other variables such as average annual daily traffic, alignment, geometry and weather condition were also considered. Based on the outcomes, IRI and number of collisions are correlated; the number of collisions increases with increasing IRI. Results suggest that IRI can be used as an indicator of diminished road safety in Alberta. Highway agencies can consider the effects of network level IRI on road safety as a decision support tool for road maintenance and rehabilitation programs.

Direct Measurement of the Impact of Heavy Loads on Thin Membrane Pavements

This paper presents the results of a field study of the loads imposed by heavy oilfield cranes (with hydraulic suspensions and super single tires) on thin membrane asphalt pavements in Alberta, Canada. Three 150-m test road sections (thin asphalt wearing course, bituminous surface treatment, and granular surface) were built and instrumented for strain at the bottom of the asphalt layer, surface deflection, and subgrade pressures. Temperature and moisture profiles were also measured. Field testing involved controlled speed experiments of standard axle configurations and heavy-axle (12,000-kg) vehicles with and without hydraulic suspensions. Focusing on the hot-mix asphalt section, this paper presents a description of the test road design, instrumentation, and testing plan, followed by some results and findings from two seasons (spring and fall 2005) of testing. Vertical stress in the subgrade, longitudinal interfacial strain, and surface deflection are compared for three vehicle types used in the test. Results from tests show that subgrade stress and interfacial strain are very similar for the standard axle configuration during spring compared with those of the cranes without the dolly during the fall season. It could be argued that on the basis of the pavement response, the cranes could operate during the winter season without the dolly (and thereby increase road safety by removing a long combination vehicle from the traffic stream) without causing substantial long-term deterioration.

Network-Level Performance Measures for Low-Volume Highways in Alberta, Canada

The province of Alberta is responsible for 30,740 km of highway, of which 4,320 km is gravel surfaced. Approximately 8,750 km (28.5%) carries traffic volumes of fewer than 400 vehicles per day. The objectives of this study are to outline network-level performance measures for highways in Alberta and to ensure that they are effective for managing low-volume highways. The performance measures used relate primarily to physical condition and functional adequacy. In 2002 these measures were studied as part of a joint project with the University of Calgary in an attempt to make them more budget sensitive. Criteria were determined and subsequently adopted by Alberta Infrastructure and Transportation. Subsequent to that, a study was undertaken to determine optimal levels for these measures. These optimal measures would be used to set desired future performance targets. The results showed that on the order of 5% of the highways should remain in poor condition and should not be part of the backlog to be corrected. It was at first thought that the majority of these highways would be low-volume roads, but this did not prove to be true, primarily because of the younger age of these roads. The study also examines the cost-effectiveness of projects to pave low-volume gravel roads in comparison with other projects in the program. Cost-effectiveness is defined as agency cost per user per kilometer over a 20-year life-cycle. In conclusion, a future direction is suggested for the department to follow with respect to its low-volume highway improvements.