bluuebunny/crossref_metadata_2025 huggingface dataset:
Artificial Intelligence-Based Architecture for Real-Time Traffic Flow Management
Authors: Sadek Adel W. , Smith Brian L. , Demetsky Michael J.
Published: April 2007

Real-time traffic flow management has recently emerged as one of the promising approaches to alleviating congestion. This approach uses real-time and predicted traffic information to develop routing strategies that attempt to optimize the performance of the highway network. A survey of existing approaches to real-time traffic management indicated that they suffer from several limitations. In an attempt to overcome these, the authors developed an architecture for a routing decision support system (DSS) based on two emerging artificial intelligence paradigms: case-based reasoning and stochastic search algorithms. This architecture promises to allow the routing DSS to ( a) process information in real time, ( b) learn from experience, ( c) handle the uncertainty associated with predicting traffic conditions and driver behavior, ( d) balance the trade-off between accuracy and efficiency, and ( e) deal with missing and incomplete data problems.
Functional Evolution of Automated Highway System for Incremental Deployment
Authors: Bayouth Michelle , Koopman Philip
Published: April 2007

A combination of market forces, cost constraints, and other factors necessitates incremental evolution of a fully automated highway system (AHS) rather than instantaneous deployment. Thus, an understanding of the interdependencies among required AHS functional capabilities is essential for planning. In this paper a set of three AHS functional evolution reference models is proposed that include essential as well as supplemental functions. The reference models include lateral motion handling, longitudinal motion handling, obstacle handling, and selected infrastructure support functions. This family of three models is used to present the needs of baseline autonomous tactical vehicle operation, the benefits of adding inter-vehicle communications, and the benefits of adding infrastructure support. The reference models reveal a critical need for vehicle motion prediction capability and suggest that both communications and infrastructure support are beneficial but not mandatory for achieving an AHS. Furthermore, there appear to be a number of safety and efficiency benefits that can be realized with only partial automation and in some cases no automation. These results could help set priorities and guide strategies for incremental introduction of AHS technology into vehicles and roadways.
Automated Highway System Field Operational Tests: Potential Sites, Configurations, and Characteristics
Authors: Hall Randolph W. , Thakker Viral , Horan Thomas A. , Glazer Jesse , Hoene Chris
Published: April 2007

In 2002 the National Automated Highway System Consortium (NAHSC) is scheduled to complete its work on development of an automated highway system prototype. Upon completion of its mission, NAHSC is likely to be followed by one or more field operational tests (FOTs) in which ordinary drivers will use automated vehicles on a real roadway under test conditions. Described are objectives for such a test, potential test sites in California, and the merits of these sites for conducting different types of tests. The evaluation is based on interviews with local officials, visits to 14 sites around the state, and collection of detailed data on these highways. It is concluded that there exist many potential FOT sites provided that the federal government pays for a large portion of infrastructure costs and that the new infrastructure is turned over to local agencies upon completion of the test.
Opportunities for Progressive Deployment of Intelligent Transportation Systems/Automated Highway System Technologies in Support of Commercial Vehicle Operations
Authors: Klingenberg Bjorn
Published: April 2007

The U.S. Department of Transportation has undertaken the Intelligent Vehicle Initiative (IVI) to improve transportation safety and productivity by accelerating the progressive deployment of intelligent transportation systems/automated highway system (ITS/AHS) technologies. Commercial vehicle operations (CVO) stand a unique chance to benefit from this initiative. Truck manufacturers and the trucking industry have made great progress in raising the standards of safety and operating efficiency over the past few years, but further significant advancements can be accomplished only by increased automation of vehicle controls and operations. That opportunity is addressed.
Innovative Financing Methods for Local Roads in Midwest and Mountain-Plains States
Authors: Hough Jill , Smadi Ayman
Published: April 2007

Budget constraints for transportation projects is a growing problem at the federal, state, and local levels. At the same time, several changes have been affecting demands placed on the transportation systems, for example, population shifts, changes in travel patterns, and changes in economic activity. County and local governments are faced with increased demands on some portions of their road systems, and other portions have seen a drop in the level of use. As a result, these transportation agencies are facing tremendous challenges to maintain their extensive road networks and provide improvements when and where needed. Traditional funding sources are no longer adequate. There is a great need for counties to explore innovative methods to increase revenues or decrease costs or both. However, because of the nature of rural states (i.e., low population density and a limited tax base), methods used to supplement public funding of transportation projects in urban areas may not be applicable. Described are 4 innovative financing methods (e.g., rural improvement districts) and 14 cost reducing strategies (e.g., sharing equipment) used by local governments in eight rural states. County road officials identified these methods through a mail questionnaire and rated key criteria, such as ease of collection, to evaluate each method before implementing it. Rural improvement districts, special assessment districts, and the wheel tax were identified as innovative methods that are not widely used to raise revenues for a county road system. Advantages and disadvantages of each innovative financing method identified are discussed.
How To Get the Best Value for Money Spent on Finnish Minor Roads
Authors: Parantainen Juha , Meriläinen Antti
Published: April 2007

The total length of the Finnish minor road network is about 345 000 km (214,373 mi). The Finnish National Road Administration is responsible for some 65 000 km (40,389 mi) of minor roads, which are called public roads. The remaining 280 000 km (173,984 mi) are private roads that are constructed and maintained mainly by property owners who usually form cooperative societies that take care of this in practice. The role of raw wood haulage is significant, representing about three-fourths of the transported tons if mainly short-distance gravel transportation is excluded. Annual rehabilitation and maintenance funding needs were estimated to be at the level of 750 million to 800 million FIM by using a network management system. The available funds should be allocated to locations where improvements lead to the widest possible positive effects for freight transportation and settlement. For freight transportation this means that frost-damaged road sections should be eliminated from locations that have the widest effects on the utilization of wood resources. To promote development in rural communities funds should be allocated for access roads to communities where other prerequisites for development also exist. The interface between public and private roads needs to be reassessed. The concept of private roads is a very inexpensive and effective way of maintaining low-volume roads.
Teamwork and Technology Transfer in Low-Volume Road Safety
Authors: Kagoro Chobya Light A. , Eck Ronald W. , Wyant William D.
Published: April 2007

The roles of teams and technology transfer in enhancing safety on low-volume roads are addressed. Roadway safety is a multidisciplinary science involving several elements: ( a) the three components of the roadway system—people, vehicle, and roadway; ( b) the agencies and groups that plan, design, build, and use roads and promote roadway safety; and ( c) the public health and safety communities that are concerned with injury prevention, response, treatment, and rehabilitation. Often the people working within these separate elements are characterized by interests, methods, and means limited by the boundaries, real or perceived, of their disciplines, organizations, and cultures. The application of technology transfer and teamwork enhances the efficacy of efforts to focus these elements on issues and problems related to roadway safety. Three broad topics are discussed. First, the importance of integrating the efforts of technical and nontechnical people and organizations through the development and management of multidisciplinary working groups and teams is explained. An associated topic is the conflict and ambiguity expected with expertise roles, boundary roles, and culture. Second, the importance of technology transfer in establishing and maintaining roadway systems used by motor vehicles, nonmotorized vehicles, and pedestrians and in educating and training engineers, engineering technicians, and the general population to design, build, maintain, and use roads safely is highlighted. Third, the importance of existing agencies in providing an organizational infrastructure that may either facilitate or hinder roadway safety planning and operations is described.
Low-Volume Roads and the Grade Crossing Problem
Authors: Russell Eugene R. , Rys Margaret , Liu Libo
Published: April 2007

Summarized are problems associated with low-volume road (LVR) passive grade crossings, low-cost innovative devices that have been developed and tested to improve safety, policies, and programs that have been developed and promoted in the United States to enhance safety at LVR grade crossings, particularly at night. On the basis of safety studies and years of experience, conclusions and recommendations are presented to reduce drivers’ risk at the typical passive, rail-highway grade crossing found on LVRs. Stressed are the two keys to reducing risk at LVR, passive grade crossings: provide adequate sight distance and make the crossing and warning devices conspicuous, particularly at night.
Causal Factors for Accidents on Southeastern Low-Volume Rural Roads
Authors: Stamatiadis Nikiforos , Jones Samantha , Aultman-Hall Lisa
Published: April 2007

Low-volume roads comprise a significant portion of the rural roadway network. Because of documented higher crash frequencies and more severe injuries on such roads, it is necessary to further examine causal factors of these crashes and to determine if crash characteristics follow the patterns of other highways. The quasi-induced exposure technique is used to analyze the relationship of driver, roadway, and environmental factors involved in crashes on low-volume roads. Crashes from Kentucky and North Carolina for 1993–1995 are used. The results show that ( a) low-volume roads present similar crash trends as those observed on other roads; ( b) drivers under the age of 25 and drivers over the age of 65 have higher crash propensities than middle-aged drivers; ( c) female drivers are safer on average than male drivers; ( d) young drivers (under the age of 25) experience more single-vehicle crashes and drivers over 65 are more likely to be involved in two-vehicle crashes; ( e) drivers of older vehicles have higher two-vehicle crash propensities on low-volume roads than drivers of newer vehicles; ( f) in single-vehicle crashes, drivers of older vehicles are more likely to have a serious injury than drivers of newer vehicles; and ( g) large trucks have the highest two-vehicle crash propensity on low-volume roads, followed by sedans, pick-up trucks, vans, and station wagons.
Starting a Safety Improvement Program for Rural Unpaved Roads
Authors: Caldwell R. Craig , Wilson Eugene M.
Published: April 2007

A prototype safety improvement program (SIP) developed specifically for unpaved roads is presented. The combination of high mileage, low traffic volume, and limited budgets makes it difficult for local agencies to adopt traditional SIPs. The presented SIP for unpaved roads is economically and procedurally appropriate for local road agencies. It provides a systematic means of prioritizing road sections for safety analysis and identifying safety improvement needs. One of the many unique features of the program is its “partnering” approach of involving public road users in the safety improvement process. Results of case studies that validate the procedure are included.
Reinforced Soil for Bridge Support Applications on Low-Volume Roads
Authors: Adams Michael , Ketchart Kanop , Ruckman Albert , Dimillio Albert F. , Wu Jonathan , Satyanarayana Raghu
Published: April 2007

A quick and simple method of bridge substructure construction using geosynthetic reinforced soil (GRS) is illustrated. GRS is used to build abutments and pier foundations for simple bridges. It is a refinement of existing reinforced soil technology used during the last 20 years. The interaction of a closely spaced geosynthetic reinforced soil system and the reasons why conventional design methods are not appropriate for these closely spaced systems are explained. This method is not recommended for all bridge building assignments; for example, it is not suitable for construction of permanent bridges in scour zones. The technique is ideal for remote locations, inaccessible to use of concrete and other traditional materials. A generic style of GRS construction is explained to ensure performance and internal stability. Construction is rapid with conventional equipment. The materials are common, inexpensive, and generally available. An overview of recent full-scale research is provided. The results of two full-scale prototype tests are presented to demonstrate performance and limitations and to confirm the design of such systems. A case history is presented that shows the versatility of the technology in a bridge support application. A procedure for prestraining or preloading the reinforced soil to enhance performance is provided. For bridge support applications, preloading of the GRS has the benefit of limiting postconstruction creep settlement. Preloading also proof-tests the structure and verifies the quality of construction. Additional sketches are included to show its potential for common applications. A brief discussion about design considerations to limit potential problems is offered.
Materials for Sealed Low-Volume Roads
Authors: Paige-Green Phil
Published: April 2007

Many unsealed roads carry relatively high traffic, which results in excessive maintenance requirements and costs. Sealing of these roads with a bituminous surfacing is typically cost-effective if minimal upgrading of the existing road needs to be done. An extensive evaluation of more than 50 roads that were constructed with base course materials of marginal quality, many with only a single layer of material over the subgrade, was carried out. Detailed evaluations of the in situ and laboratory properties as well as the performance of the roads indicated that good drainage and construction quality are the primary requisites for successful sealed low-volume roads. Provided these two criteria are met, current material standards and pavement designs can be significantly relaxed. The use of these light pavement structures results in significant environmental benefits compared with the construction of traditional pavement structures through conservation of higher quality materials, reduced energy usage through less haulage, and elimination of gravel loss and dust emission from the roads.
Development and Implementation of a Construction Material Information System
Authors: Woodbridge M. E. , Cook J. R. , Moestofa B.
Published: April 2007

The exploitation of aggregates and soils for highway construction has a considerable impact on the economy and the environment and it is important that utilization of these materials is cost-effective. Obtaining and maintaining good records is costly and requires professional expertise. With modern computer technology it is possible to store information systematically and compactly. If quarry information is available in one central locality, better planning of road construction and maintenance and better management of materials resources can be realized. The research undertaken to create a materials information system in Indonesia is described. A pilot system was designed and tested in the province of West Java and comprehensive data collected from about 800 quarry sites. The Indonesian Directorate General of Highways, encouraged by the results of the pilot study, decided to introduce the system to all 27 provinces of Indonesia. Training courses were held to teach good practice and were successful because of improvements in the quality and quantity of data provided, but there is still scope to improve the utilization of the system by potential users. With accurate data the system is an improvement on the status quo. The system is simple to use, can be updated when necessary, and provides the basic information required by highway engineers. It is transferable to other countries in transition with minimal alteration. The data can be used in conjunction with terrain classification and Geographic Information Systems packages (such as MapInfo) to indicate potential new material sources.
Three Road-Crushing Demonstration Projects
Authors: Bassel James R. , Edwards Anthony , Leibbrand Lou , Keller Gordon , Dauer William
Published: April 2007

At the Sixth International Conference on Low-Volume Roads Yves Provencher, Forest Engineering Research Institute of Canada, presented a paper on the F.A.H.R. rock crusher mounted to a front-end loader. At the same time the Coronado National Forest in Arizona was renting a F.A.H.R. rock crusher for an in-place road-crushing project. In 1997 San Dimas Technology and Development Center, in partnership with the Coronado National Forest, sponsored two demonstration projects to further test the crusher at unique locations to gain additional information from actual field trials. These projects were located on the Rio Grande National Forest in Colorado and the Plumas National Forest in California. The three projects are described here, with results and conclusions gained from the demonstration projects. The concentration is on the characteristics of the processed material. Samples taken from windrows during the crushing operation were tested to determine hardness and gradations before and after crushing. Cost varied from $8 to $26 per m3 including roadbed preparation, crushing, and blading. Rocks and boulders to 405-mm maximum size were crushed. The processed material has a maximum size of 50 to 75 mm. The product produced by the crusher offers a viable alternative for aggregate on a road surface, particularly as a road surface cushion material, where the quality and expense of standard crushed aggregate, such as base course material, are not needed on low-volume roads.
Recent Australian Experience with In Situ Stabilization
Authors: Moffatt Michael A. , Sharp Kieran G.
Published: April 2007

For reasons of climate and economy, Australia’s roads are typically of light construction. However, new challenges are emerging as the primary road network nears completion and the volume, mass, and tire pressures of road freight vehicles increase. In 1986, Austroads issued their “Guide to Stabilisation in Roadworks” and, since that time, a great deal of research has been conducted in Australia to improve the in situ stabilization processes from the point of view not only of pavement thickness design but also of construction and rehabilitation practice. In situ pavement recycling by incorporating a cementitious binding agent has long been recognized as an economical way to strengthen pavements. The main problems have been the use of thin layers combined with short working times, resulting in high roughness and subsequent delamination of layers, pumping of fines, and excessive cracking. However, the recent development of deep-lift recycling equipment and specialized binder spreaders, together with the more ready availability of a range of slow-setting binders (granulated slag, fly ash, and lime) and high-performance compaction equipment, have allowed the development of deep-lift stabilization techniques. A brief background of Australia’s roads and recent developments in the use of in situ stabilization in Australia are presented, and recent tests with the accelerated loading facility to assess the suitability of bitumen/cement and slag/lime blends, the latter incorporated in both thin (200 mm) lifts and thick (400 mm) lifts, and the impact of this research on practice, are summarized.
Effectiveness of Portland Cement and Lime in Stabilizing Clay Soils
Authors: Prusinski Jan R. , Bhattacharja Sankar
Published: April 2007

Pavement subgrades constructed with clay soils can cause significant pavement distress because of moisture-induced volume changes and low subgrade support values. Lime is well known for its ability to stabilize plastic clays; however, portland cement also provides highly effective clay stabilization, usually with the added benefit of higher strength gain. Stabilizing clays with cement or lime can improve subgrade properties at a lower cost than either removing and replacing material or increasing the base thickness to reduce subgrade stress. The clay soil stabilization mechanism for the calcium-based stabilizers portland cement and lime is reviewed. These materials modify soil properties through cation exchange, flocculation and agglomeration, and pozzolanic reaction. Additionally, cement provides hydration products, which increase the strength and support values of the subgrade materials as well as enhance the permanence of the treatment. Comparative laboratory and field performance studies by others, focusing on stabilization of clay soils with portland cement or lime, are critically reviewed. Several factors affecting stabilization are discussed, including stabilizer test procedures, dosage effects to soil properties, mixing, compaction, and gradation and pulverization. Additionally, durability of cement and lime as stabilizers is reviewed, including wetting and drying, freezing and thawing, leaching, and long-term field performance. The research reviewed indicates that, if proportioned and applied properly, both cement and lime can effectively improve the engineering properties of clay soils over the life of a pavement. The results presented provide a guide to the engineer about the property changes to expect when using portland cement and lime with regard to volume stability, strength, and durability.
Field and Laboratory Evaluation of the Use of Lime Fly Ash to Replace Soil Cement as a Base Course
Authors: Shirazi Hadi
Published: April 2007

The performance of lime and fly ash-stabilized base as an alternative to soil-cement-stabilized base for flexible pavement systems on reconstructed highways in Louisiana is evaluated in this study. Historically Louisiana has used soil cement for most flexible base construction because of its low cost, high compressive strength, and ease of construction. However, soil cement is subject to excessive cracking due to shrinkage, which may decrease the expected pavement life. Lime and fly ash bases exhibit many of the same properties as soil-cement bases with potential for less shrinkage cracking. Lime and fly ash (Class C fly ash) test sections were installed on two Louisiana highway reconstruction projects in the northwestern part of the state. For each project, two 0.4-km (0.25-mi) test sections with different percentages of lime and fly ash were constructed. The remainder of each project was constructed with 8 percent soil-cement base by volume. On both projects, the first test section used 2 percent lime and 4 percent fly ash by weight for stabilization and the second test section used 3 percent lime and 6 percent fly ash. Test specimens were molded in the field during construction by using stabilized base material taken from the roadway immediately before compaction. Laboratory test specimens were made later with materials taken from, but not mixed at, the construction sites. Both field and laboratory samples were tested in unconfined compression at 7, 28, and 56 days. The overall unconfined compressive strength of lime and fly ash was 30 percent lower than that of soil cement.
Holistic Approach to Research into Dust and Dust Control on Unsealed Roads
Authors: Jones D.
Published: April 2007

Aspects of dust and dust control have been studied for many years in most countries with unsealed road networks. However, no comprehensive coordinated study to investigate the processes affecting the generation of road dust, road dust measurement, road dust prediction, acceptability criteria for dust, or the performance of dust palliatives has been undertaken. Over the past 6 years, the Council for Scientific and Industrial Research has been engaged in such a study. Although research has been undertaken on behalf of numerous parties, experimental designs have been coordinated in an attempt to develop guidelines for the responsible use of dust palliatives. Unfortunately, many of the experiments that have been undertaken by product manufacturers and road authorities over the years have been uncoordinated and poorly monitored, with minimal information being recorded or published. Many of these experiments have failed, with the product always being blamed, and this, together with poor marketing techniques used by suppliers, has led to skepticism by the roads industry toward the use of the products. Scientific research, following detailed experimental designs, funded by the product suppliers has resulted in the development of guidelines for the use of certain products. Studies have shown that, provided the products are used under appropriate circumstances, they can provide a cost-effective interim measure to improve the quality of life and preserve construction materials until such time as the road can be upgraded to a sealed surface. The holistic approach to dust and dust control research that has been followed is discussed here, a summary of the findings is described, and recommendations toward implementing a dust-control program are made.
Geological Factors Affecting Performance of Unsealed Road Materials
Authors: Paige-Green Phil
Published: April 2007

Nearly all structural layers in roads originate as geological materials. The geological origin and chemical and mineralogical composition of these rocks varies considerably and after natural weathering processes affect the fresh rock, a wide range of potential construction materials evolves. After noting that the performance of geological materials in roads is better predicted by an engineering geological classification than by a strictly geological classification, an engineering geological classification system was developed in southern Africa during the late 1960s. This classified materials on the basis of their weathering potential, and products related to their expected performance in roads and the characteristics of each group are discussed. It is shown from an investigation of the performance of a wide range of materials used in unsealed road wearing courses that the engineering geological classification of a material cannot be used to predict accurately its performance in unsealed roads. Factors including mineralogy, geological structure, stage of weathering, local hydrological conditions, and the prevailing and past climate all have a major influence on their performance. Laboratory-determined geotechnical test results are necessary for acceptable classification purposes. The variability of these materials after weathering, however, increases the risk of their use and makes selection more difficult. Mechanisms for selecting and treating appropriate materials for use in unsealed roads are suggested.
Evaluation of Stabilized Bases, Double Sand Seal, and Slurry Seal Pavement Sections in the Sultanate of Oman
Authors: Ali Galal , Taha Ramzi , Muscati Mohammed , Al-Rasheidi Abdel-Aziz
Published: April 2007

Petroleum Development Oman undertook a study in 1996 to evaluate the use of a sulfonated petroleum product (SPP) as a base/subbase stabilizer and the performance of slurry seal and double sand seal in paving applications. Eight different road sections were constructed for a total length of 23.3 km. They constituted part of Marmul-Thumrait road project where the average traffic is about 150 vehicles per day. The objective was to improve the performance of graded roads and provide a low-cost base suitable for application of a thin bituminous surfacing. All eight sections were constructed with the standard subbase and base layers specified for roads in the Sultanate of Oman. However, major exceptions were as follows: Section 1, a slurry seal surface on normal resheeted base; Section 2, a slurry seal surface on SPP-stabilized base and subbase; Section 3A, unstabilized base and subbase (control section); Section 3B, SPP-stabilized base and subbase with a slushed finish carried out during construction; Section 4A, SPP-stabilized base and subbase with a slushed finish carried out a period of time after pavement construction; Section 4B, SPP-stabilized base and subbase; Section 5, a double sand seal surface on SPP-stabilized base and subbase; Section 6, a double sand seal surface on normal resheeted base. Road sections were monitored monthly for 6 months. The evaluation program included visual assessment of the surface, riding quality, dust generation, gravel loss, rutting, and in situ strength with a dynamic cone penetrometer. There were no differences in gravel loss, dust generation, strength values, or signs of distress between the stabilized and unstabilized sections. For the paved roads, the slurry seal section with SPP-stabilized base and subbase displayed the best performance in terms of less rutting and bleeding.
Design of Rehabilitation Treatments for New Zealand’s Thin-Surfaced Unbound Granular Pavements
Authors: Arnold Greg
Published: April 2007

Most thin-surfaced unbound granular pavements are rehabilitated by overlaying with an unbound granular material and surfaced with a chip seal (thin-surfacing). The unbound granular overlay thickness is the difference between the total granular thickness required for future traffic and the granular thickness required for past traffic as determined from the design chart. However, where there are signs of shoving or other indications of a weak and degraded aggregate base layer then a smoothing treatment will not be adequate. For this situation the appropriate rehabilitation is either in situ stabilization (to improve the strength of the aggregate base material) or to cover with a minimum thickness of unbound granular material (determined from the thickness design chart by assuming the existing pavement acts as a subbase). This method of unbound granular overlay design has resulted in significant cost savings over the past 20 years in rehabilitation treatments for New Zealand roads, as the existing pavement has been fully utilized. In 1995 New Zealand adopted the Austroads (the Association of State, Territory and Federal Road and Traffic Authorities in Australia) procedures for pavement design. The Austroads procedures encourage the use of mechanistic procedures for pavement design. By using the same assumptions as the design chart method for determination of granular overlay depths, a mechanistic design procedure for rehabilitation treatments was developed. This method produces comparable results and has the advantage of being able to design a range of rehabilitation treatments.
Lessons Learned from the Failure of a Bituminous Surface Treatment in Central Oregon
Authors: Bolander Peter , Chitwood Lawrence A. , Steele H. Michael
Published: April 2007

During October 1996 a 10-km-long, double-lane, two-layer bituminous surface treatment (BST) was constructed near Bend, Oregon. The bottom BST layer consisted of an application of rapid setting high float emulsion (HFRS-2) followed by an application of 19- to 12.5-mm chips. The top layer consisted of various emulsions and 13- to 6.3-mm chips. Soon after construction up to 20 large commercial timber hauling trucks per day used the road during the wettest November and December in over 20 years. By the end of December 1996 most of the top layer of chips had disappeared, large numbers of potholes had developed, and the emulsion was not adhering to the bottom layer of chips. Failure resulted from interacting factors including a dust coating on the chips, an incompatibility of emulsion and chips, cold and wet weather, and a nearly impervious base course. The following lessons were learned from this project: ( a) An adequate and accurate quality control and quality assurance plan should be in place before construction. ( b) In wet environments, base courses under a BST should be free draining. ( c) Either cool and humid construction weather or dust coatings on the aggregate may not lead to failure, but in concert they raise the potential for failure dramatically. ( d) Not all emulsions are manufactured the same. An emulsion’s break and cure time may vary depending on the emulsion’s additives. ( e) The asphalt emulsion and aggregate must be compatible with each other at conditions expected on the road surface.
Design Guidelines for Low-Volume Macadam Pavements in South Africa
Authors: Visser Alex T. , Hattingh Johan
Published: April 2007

Macadam principles in pavement engineering were applied in South Africa up to around 1960. Mechanization and increased production requirements led to a decline in the use of macadam layers. More recently interest in macadam pavements in South Africa was renewed because of the labor-friendly construction methods. Much of the experience that had been available was lost as people retired, and new techniques of construction gave a new perspective. There is thus a need to provide guidance to new entrants to the industry and capture the experience that was common knowledge several decades ago. The aim of this report is to present a guideline document for construction of appropriate and economic macadam pavements based on extensive South African research coupled with vast experience in the construction of these layers. Guidance on appropriate use of the different variants of macadam layers, the material properties, the structural design process and catalogue, functional design considerations, and construction practice is provided. It was found that under the current socioeconomic upliftment program macadam principles provide an appropriate and cost-effective solution to paving urban streets.
Design and Evaluation of Very Low-Volume Rural Roads in Developing Countries
Authors: Gannon Colin , Lebo Jerry
Published: April 2007

Design and evaluation methodologies for low-volume rural roads have traditionally followed an agricultural focus, with an understanding that improved transport, by lowering transport costs, supports economic development through expanding exports and local incomes. More recently, the role of low-volume roads as a crucial complementary input to other activities has been recognized, especially the delivery of essential health and educational services, exchange of information, and basic social interactions. However, limited analytical work has been done to ensure that these benefits are systematically incorporated in the planning and evaluation of transport projects, and experience suggests that the current emphasis of design and evaluation on agricultural benefits can lead to inappropriate priorities and design standards, inasmuch as these are still typically guided by trading off infrastructure life-cycle costs (construction and maintenance) against motorized user savings (vehicle operating costs) and/or increased net income/value-added. There is a need to be more discerning in the application of existing methodologies, as well as to systematically incorporate the socioeconomic role of rural transport infrastructure (including poverty alleviation) into prioritizing improvements. Key to this analysis is the proposition that appropriate design standards need to balance the transport requirements of core economic and social activities with the impact of geography (geology, topography, and climate) on construction and maintenance costs. By taking into account the broader range of impact on local users, the proposed approach encompasses a wide array of options for providing minimum-cost, reliable infrastructure for both motorized and nonmotorized transport.
Applications for Geosynthetics on Forest Service Low-Volume Roads
Authors: Powell William , Keller Gordon R. , Brunette Bruce
Published: April 2007

Today’s geosynthetic products have many useful, creative, and cost-effective applications for rural, low-volume roads. In the management of almost a half-million km (quarter-million mi) of low-volume roads, the U.S. Department of Agriculture, Forest Service (USFS), has developed and adopted many uses for geosynthetics. An overview is presented of many of those uses and their advantages. The USFS gained much of its experience and practice with geosynthetics while constructing a wide variety of Mechanically Stabilized Earth (MSE) retaining walls, including geotextile, timber, modular-block, and tire-faced structures, and reinforced soil slopes. More recently, the USFS has used geosynthetics for MSE bridge abutments and Deep Patch road-shoulder reinforcement. Other typical geosynthetic applications include filtration, drainage, subgrade reinforcement, and erosion control.
Areawide Performance-Based Rehabilitation and Maintenance Contracts for Low-Volume Roads
Authors: Cabana Guillermo , Liautaud Gerard , Faiz Asif
Published: April 2007

To address internal inefficiency and accountability issues, a number of Latin American countries have moved decisively and successfully over the last decade from force-account (direct labor) to contract maintenance. Also, there has been considerable progress in the region in transferring to the private sector, through concessions, the responsibility for improving, maintaining, and operating high-traffic-volume roads, the cost of which is recovered from tolls. Argentina, Brazil, and Chile are among the most advanced countries in this respect. More recently, some countries—particularly Argentina—have switched from the traditional quantities and unit price–based short-term maintenance contracts to long-term performance-type or results-based contracts. The new approach encompasses either routine maintenance activities alone or integrated contracts involving both the rehabilitation and routine maintenance of road networks. The latter form, the so-called CREMA system (Contrato de Recu-peración y Mantenimiento), is now being implemented in Argentina and covers approximately 12 000 km (i.e., about 40 percent of the national paved road network). Such contracts comprise the rehabilitation and subsequent maintenance over a 5-year period of 200-km- to 300-km-long subnetworks. A framework for extending the CREMA concept to low-volume roads is presented. The means by which this newly developed system could be extended to cover both the paving and future maintenance of low-volume roads is explained. Reasons are analyzed as to why this type of contract, which extends the contractor’s share of responsibility over a relatively long period of time, would be well suited to the specific design and construction features of low-cost, low-volume paved roads—in particular, in the risks related to uncertain traffic projections and in the use of local or nontraditional materials in thin pavement structures. Finally, issues related to the use of the CREMA system—especially the need to prepare adequate contract bidding documents, conduct proper bid proposal evaluations, and monitor contractor’s performance during the rehabilitation/paving and maintenance phases—are explored.
Use of Low-Cost Agricultural Implements in Low-Volume Road Construction
Authors: Mathur Sudhir , Soni S. K. , Murty Avsr
Published: April 2007

In India there are 0.6 million human settlements scattered all over the country. Forty-eight percent of these villages are connected with all-weather roads and the remaining 52 percent of these villages are yet to be connected with all-weather, black-topped roads. The prevailing construction methodologies that use mechanized implements do not suit the construction of low-volume roads in India due to the high cost of machinery and unavailability of skilled labor and technicians. In view of the above, the present methods of low-volume road construction and maintenance are largely labor-based. These methods are slow and often result in substandard quality of construction. Therefore, it is considered essential to adopt an appropriate man-machine combination. Such an approach will be necessary in the future to improve the standards of construction required for low-volume road infrastructure development and also to meet the accelerated pace of rural developmental activities. Cultivation and farming are the main activities in the villages leading to the availability of farming tractors and other related implements. Since tractors are increasingly available in large numbers in rural areas, it is considered most appropriate to make use of various agricultural implements towed by tractors for the different road construction operations. A survey was made of the existing agricultural implements suitable for carrying out the various road construction operations. Based on results of this study, different farming implements were used for various road construction activities on demonstration projects. The data obtained from these projects were analyzed to determine the technical and economic feasibility of labor-intensive and tractor-towed equipment construction techniques. An economic evaluation of these low-cost road construction techniques was performed to identify relative cost factors. Different low-cost agricultural implements and their possible use in various road construction operations are highlighted. Based on these studies, it is evident that the deployment of tractor-based techniques would result in substantial economy with the added benefit of better-finished quality of work and considerable time-saving in projects.
Geographic Information Systems-Based Pavement Management System: A Case Study
Authors: Medina Alejandra , Flintsch Gerardo W. , Zaniewski John P.
Published: April 2007

A case study in which the researchers developed a prototype low-volume roads pavement management system (PMS) using a geographic information system (GIS) platform for Fountain Hills, Arizona, is described. The approach used and the problems faced are discussed. The first stage of the study entailed the collection of all information available from the city. City engineers provided a database with inventory and condition data, and an AutoCAD map of the city streets. The research team then evaluated several software packages. They selected the Road Surface Management System (RSMS) package developed at Arizona State University for the PMS portion. This program was developed to help local Arizona agencies systematically manage low-volume road and street pavements. The researchers evaluated two GIS packages for the study, based on the software’s capabilities and the city’s needs. They selected Maplnfo because it was less expensive and easier to learn. A menu-driven MapInfo application that runs the RSMS software, imports the pavement maintenance and rehabilitation program, and interactively prepares and displays colored maps with the analysis results was finally prepared. The combination of RSMS and MapInfo significantly reduced the effort required to develop the prototype system. It allowed the development and implementation of a GIS-PMS for the city, based on the existing digital data. City engineers were very impressed with the prototype system’s capabilities.
Prioritization Procedure for Improvement of Very Low-Volume Roads
Authors: Airey Tony , Taylor Gary
Published: April 2007

A practical methodology for prioritizing road works on low-volume and very low-volume roads in the rural areas of developing countries is described. The methodology is based on a system for estimating future traffic on improved roads on the basis of readily available data. Moreover, the method accommodates the need to consider the opening of roads that may be currently impassable to motor traffic. The procedure is simple and transparent, and therefore it is well suited to implementation at the district level. It allows for certain basic parameters, such as minimum thresholds for viability of investments, to be set by decision makers, thereby permitting and defining the role of politicians in the process.
Predicting Pavement Deterioration Modes Using Waveband Analysis
Authors: Hassan R. , Mcmanus K. , Holden J.
Published: April 2007

Road roughness is the result of a chain of distress mechanisms, and it combines the effects of various modes of pavement deterioration. The common measure of roughness is the international roughness index (IRI). The IRI represents the functional performance of road pavements and serves as an indicator of the structural performance. However, the use of the IRI in setting priorities for maintenance and rehabilitation programs has some flaws. The IRI cannot detect the mode and rate of pavement deterioration that contribute to the surface roughness. In addition, the IRI may be a poor measure of truck ride and the dynamic wheel loads generated by the interaction of heavy vehicles and rough road surfaces. Roughness spectrum can be divided into certain wavebands, with each waveband corresponding to a certain mode of pavement deterioration. The power spectral density analysis of road profiles is used to view the distribution of the various wavelengths within the profile and to show the contribution of each waveband to roughness. Waveband analysis can help overcome the shortcomings of the IRI, and it provides information that helps road authorities in planning rehabilitation programs and managing the road network.
Removing Spring Thaw Load Restrictions from Low-Volume Roads: Development of a Reliable, Cost-Effective Method
Authors: Kestler Maureen A. , Hanek Gordon , Truebe Mark , Bolander Peter
Published: April 2007

Low-volume roads in areas of seasonal freezing are highly susceptible to damage from trafficking during spring thaw. To minimize pavement damage, many agencies and states impose load restrictions during periods in which damage is most likely to occur. However, the magnitude and duration of reduced or prohibited hauling vary widely among agencies, and an optimal balance between maximizing local economy and minimizing road damage is rarely achieved. The U.S. Department of Agriculture Forest Service and the U.S. Army Cold Regions Research and Engineering Laboratory are evaluating a quantitative technique for removing load restrictions by developing correlations between pavement stiffness and soil moisture. Laboratory tests of the moisture sensors showed them to be accurate and repeatable under adverse freeze-thaw cycling. Preliminary analysis of field data showed that permanently installed time domain reflectometry and radio frequency soil moisture sensors strategically located throughout the forest road network will provide an affordable method for quantitatively determining when to remove load restrictions. Load restriction practices are reviewed, economic ramifications on the forest industry are briefly discussed, and laboratory and field test programs conducted to monitor soil moisture and pavement stiffness are outlined. In addition, instrumentation used for the study is described, observations from one of four national forest pavement test sites are presented, and the ongoing research to develop a method to remove load restrictions is discussed.