bluuebunny/crossref_metadata_2025 huggingface dataset:
Motorcycles as a Full Mode of Transportation
Authors: Wigan Marcus
Published: April 2007

Motorcycles usually are treated solely on the basis of their safety characteristics and very rarely as a mode of transportation with benefits and costs, placing safety issues in a full transportation context. The standard transportation issues of traffic flow effects, driving cycles, rider mode choice behaviors, and economic evaluation have largely been neglected for motorcycles. A survey of existing and new Australian and other data was undertaken and the data assessed, along with topics covered in a more comprehensive Australian study. Geographic information system techniques for integrating motorcycle flow estimation and crash data were also assessed. Attitudinal work shows a strong propensity for motorcycle owners to enjoy not only their motorcycle travel but all other forms of travel more so than those who do not have access to motorcycles. Practical policy directions are proposed to bring motorcycles onto an equal information and analysis footing as other modes, for a coherent treatment of road capacity management and for using vulnerable road users as an anchor in an integrated policy and planning context.
Older Road Users: Examining the Relationship Between Injuries and Fatalities
Authors: Wagner Essie K. , Gotschall Cathy
Published: April 2007

For years, researchers have examined the older-driver problem of increased fatalities relative to population or miles driven. Existing data were analyzed to determine whether the frailty explanation of the fatality rates of older people offers a complete picture. Fatality-to-injury ratios were calculated by using the fatality analysis reporting system, general estimates system, and national accident sampling system data. An increase was found in the number of fatalities related to age—the older the victim, the greater the probability of death. This was no surprise. However, there was a surprise regarding belted versus unbelted occupants: unbelted older occupants (drivers or passengers) are at a dramatically increased risk of being killed in a crash than those who are belted. This suggests that potential improvements to occupant protection within the vehicle, although important, may have less to offer older people than the simple use of seat belts.
Older-Driver Perception of Problems at Unsignalized Intersections on Divided Highways
Authors: Eck Ronald W. , Winn Gary
Published: April 2007

West Virginia has one of the oldest populations in the country. As the Appalachian Development Highway System expands, many older drivers are, for the first time in their driving experience, encountering at-grade intersections on high-speed divided roadways. Because older drivers generally demonstrate an increased accident involvement at at-grade intersections, a study was undertaken to assess understanding by West Virginia’s older drivers of the associated geometric design features and traffic control devices. A self-administered survey was completed by 172 participants at 15 senior centers in counties that have corridor highways within their boundaries. Respondents ranged in age from 50 to 91. Almost two-thirds of the respondents were female. About 44% of respondents indicated that they voluntarily limited their driving, mainly because of difficulties driving at night. Overall, crossing the divided highway was perceived as less difficult than making left turns. Making left turns onto the divided highway was perceived as the more difficult of the turning movements. Approximately one-half of the participants indicated that they did not have problems making left turns onto the divided highway. Large trucks and rudeness or dangerous actions of other drivers were the most commonly cited dislikes about sections of divided highway. Responses indicated a lack of understanding about how to drive through the middle of the at-grade intersection. This issue can be addressed through traffic engineering techniques such as delineation or channelization and through development of driver educational materials.
Asking the Right Question: Understanding the Travel Needs of Older Women Who Do Not Drive
Authors: Rosenbloom Sandra , Winsten-Bartlett Cheryl
Published: April 2007

Most of those 65 and older are and will be women who have different travel patterns and resources to cope with mobility losses as they age. Older women make up the overwhelming percentage of all nondrivers, and a high proportion have limited incomes and household support with which to address their travel needs. Unpublished data from the 1995 Nationwide Personal Transportation Survey were analyzed to evaluate the differential impact of not having a license on otherwise comparable men and women. Women who do not drive face greater mobility problems than comparable men, and the mobility problems of older women are of two types: never having had the ability to drive and loss of the ability to drive. Current patterns suggest that mobility losses due to either type of nondriving will not fall evenly on men and women or among different groups of men and women.
Incorporating Nonmotorized Modes in a Mode Choice Model
Authors: Sanches Suely da Penha , Serra de Arruda Fabiana
Published: April 2007

A binary logit mode choice model that incorporates nonmotorized modes of transport was formulated. The model was calibrated with data collected at a Brazilian university campus, by means of travel diaries that were completed by students, staff, and faculty. The binary logit model gives the probability of an individual’s choosing walking or a motorized mode based on socioeconomic variables, land use characteristics, and trip length.
Sidewalk Cross-Slope Design: Analysis of Accessibility for Persons with Disabilities
Authors: Kockelman Kara , Heard Lydia , Kweon Young-Jun , Rioux Thomas
Published: April 2007

Current and proposed Americans with Disabilities Act (ADA) guidelines offer no specific guidance on acceptable maximum cross slopes where constraints of reconstruction prohibit meeting the 2% maximum cross-slope requirement for new construction. Two types of sidewalk test-section data across a sample of 50 individuals were collected, were combined with an earlier sample of 17 individuals, and were analyzed, with an emphasis on cross slopes. These tests examined heart-rate changes and user perception of discomfort levels, and they relied on a random-effects model and an ordered-probit model, respectively. Model estimates were used to deduce critical or unacceptable cross slopes for critical conditions and critical populations of persons with disabilities. Predicted values for the most severe or constrained cases ranged from 5.5% to 6% cross slope. These cases included 5% primary slope (main grade) and 45-ft-long sections; the sections were traversed by cane, crutch, or brace and manual wheelchair users who were up to 80 years old. When primary slopes were reduced to 0% in the perception estimates, the critical cross slopes for the critical case rose to 6%. For most other persons with disabilities, the critical cross slopes ranged from 6% to 9% or more. These values substantially exceed the ADA accessibility guidelines’ 2% maximum cross-slope standard for public sidewalks.
Advance Yield Markings and Fluorescent Yellow-Green RA 4 Signs at Crosswalks with Uncontrolled Approaches
Authors: Van Houten Ron , McCusker Dave , Huybers Sherry , Louis Malenfant J. , Rice-Smith David
Published: April 2007

Motorists yielding to pedestrians at the crosswalk line on multilane roads with uncontrolled approaches can screen the view of the pedestrians from vehicles approaching in the next lane the pedestrians must cross. Two strategies were designed to increase the safety of pedestrians at crosswalks with uncontrolled approaches: installation of a sign instructing motorists to yield in advance of the crosswalks, supported by yield markings, and replacement of crosswalk signs at the crosswalk with fluorescent yellow-green sheeting. Motorist and pedestrian behaviors were measured at 24 sites (12 urban and 12 rural) where motor vehicle-pedestrian conflicts had occurred. Measured were evasive action, the distance motorists stopped before the crosswalk when yielding to pedestrians, and the percentage of motorists yielding to pedestrians. Results showed that the advance yield sign and advance yield markings reduced the percentage of motor vehicle-pedestrian conflicts involving evasive action and increased the percentage of motorists yielding to pedestrians and yielding further back from the crosswalk line. Results also showed large safety benefits on multilane roads with two-way traffic, multilane roads with one-way traffic, and single-lane roads with oneway traffic. The fluorescent yellow-green crosswalk signs, although more conspicuous, produced no improvement in yielding behavior or motor vehicle-pedestrian conflicts. All results of this experiment, confirmed by statistical analysis, were found to endure during follow-up data collection 6 months after the treatments were introduced. Treatments were applied only to streets posted at 50 km/h (30 mph).
Pedestrian Level of Service for Midblock Street Crossings
Authors: Baltes Michael R. , Chu Xuehao
Published: April 2007

A level-of-service methodology for pedestrians crossing streets at midblock locations was developed. The methodology can provide a measure of effectiveness that indicates pedestrians’ perceived quality of service in crossing roads at midblock locations. An objective was to determine what variables are correlated with pedestrians’ perceived quality of service for midblock crossings. A statistical calibration and validation process involved the collection of actual site characteristics and stated levels of quality of service by a sample of persons at a selection of midblock crossing locations. The variables included those that are most important to the Florida Department of Transportation and local governments for the purpose of improving pedestrian mobility, safety, and livability. Results showed that the levels of crossing difficulty tend to increase with the width of painted medians, signal spacing, and turning movements. They also showed that both the presence of pedestrian signals and cycle length are statistically significant, although they were hypothesized to be indeterminate. Finally, the results further indicated that people tend to find that the presence of pedestrian signals lowers their level of crossing difficulty.
Geographic Information System-Based Truck Accident Information and Management System for New Jersey Roadways
Authors: Chien Steven , Li Guancheng , Daniel Janice
Published: April 2007

Geographic information systems (GIS) technology has been discussed for managing traffic accident data for years. However, its usefulness for analyzing truck accidents has not been explored extensively. Because GIS has spatial referencing and graphical display features, it would be useful to link relevant accident information to assist in information management and safety analysis. Used with other analysis technologies, GIS can help identify factors that contribute to accidents at specific locations and to identify countermeasures. The New Jersey Department of Transportation (NJDOT) has comprehensive electronic databases, including roadway networks, truck accident records, roadway geometry, and other relevant information, but use of this information remains at the level of database management. Integration of truck accident information into a GIS is a low-cost, high-benefit way to analyze factors that affect truck accidents and their associated mitigation measures. The analytical ability of a GIS-based truck accident information management system developed for NJDOT is presented.
Modifying Local Agency Pavement Management System to Support Governmental Accounting Standards Board 34 Requirements
Authors: Dewan Shameem A. , Smith Roger E.
Published: April 2007

The Metropolitan Transportation Commission pavement management system (MTC PMS) has been used by many cities and counties in the United States for more than 15 years. MTC PMS was evaluated to determine the extent to which the software can support the Governmental Accounting Standards Board (GASB) 34 reporting requirements, established in 1999. A local agency PMS can take information from a pavement network database to produce useful reports, which can be utilized jointly with the information from other assets managed by an agency to support the requirements for a comprehensive asset management system and other reporting requirements. The objective of this study was to elaborate GASB 34 requirements for reporting infrastructure assets, examine the capabilities of MTC PMS in supporting those standard requirements, and recommend any modifications of MTC PMS needed to better support GASB 34. It is evident from the study that MTC PMS has the capability, to some extent, of supporting GASB 34 for reporting on a pavement network according to both the GASB 34 reporting methods: the depreciation method and the modified approach. It partially supports the prerequisites for using the modified approach, which require that the managing agency have an asset management system with certain designated characteristics. Some modifications of MTC PMS software were proposed to make this management system more effective as a tool supporting an asset management system and overall GASB 34 requirements.
Application of Highway Development and Management Tool for Low-Volume Roads
Authors: Veeraragavan A. , Reddy K. B. Rathnakara
Published: April 2007

Connectivity is a key component of rural development in developing countries. Traditionally, many road organizations budget and program for road works on a historical basis. An objective, needs-based approach is necessary with knowledge of the content, structure, and condition of the roads being managed. The Highway Development and Management Tool (HDM-4) provides a suitable framework for such an approach. From the available traffic and condition surveys, nine representative low-volume road sections with varying geometry and pavement condition are analyzed. The types of vehicles using the roads are two- and three-wheelers; standard medium buses; standard minibuses; light commercial vehicles; two-axle trucks, cars, and tractors among the motorized traffic; and bullock cart and bicycle among the nonmotorized traffic, which are the conventional modes of transport for low-volume roads in developing countries. The purpose of the study is to forecast budget requirements and predict performance trends by applying the strategy analysis of HDM-4 to low-volume roads. The analysis was carried out for two objective functions: to maximize the net present value and to minimize the total costs for a target international roughness index. The design period was 20 years; economic indicators were determined at a discount rate of 12%. Two investment alternatives, namely, a desired maintenance and an ideal maintenance, are compared with the do-minimum alternative. The study reveals that the strategy application of HDM-4 can be used for managing low-volume roads effectively. The tool will help in forecasting budget requirements and assessing the impact of various investment alternatives.
Meeting Challenges of Rural Road Management Caused by Decreasing Population and Changes in Industrial Structure
Authors: Parantainen Juha , Meriläinen Antti
Published: April 2007

The most pronounced characteristics of rural development in Finland in the 1990s include the concentration of population in cities as well as changes in the industrial and production structure. Outlying areas of eastern, northern, and central Finland have experienced the most significant absolute and relative decreases in population in recent years. A 73% share of state-owned public roads and private roads (the lowvolume road network) is located in the areas of decreasing population. Traffic volumes will decline on low-volume roads as rural population decreases and will significantly affect the economy of low-volume road management in the future. In the areas of decreasing population, the greatest problem is to maintain the low-volume road network in adequate condition with reasonable costs to serve permanent residents and the transport needs of agriculture and forestry. The most important measures for meeting the challenges of decreasing population include the allocation of sufficient funding for the management of low-volume roads, which will provide for the basic level of service to meet the necessary needs of citizens and enterprises. Furthermore, a system of “just-for-need road management” should be adopted more widely in the management of low-volume roads. Through this system, the scarce financial resources of public low-volume road management would be allocated as efficiently as possible to meet demand by time and location. It should be noted, however, that savings through just-for-need road management are not necessarily significant, and in some cases costs may even increase. For this reason, each low-volume road segment should be examined separately.
Role of Research and Development in Road Sector Reform
Authors: Pinelo António , Carvalho Pedro , Kamhi Yitzhak , Ghzala Abdelmoula
Published: April 2007

In developing countries, research and development (R&D) in road technology has often been neglected in favor of the institutional and funding aspects of road sector reform. In the African context, where low-traffic-volume roads (LTVRs) play a key role, central to the reform efforts is the sustainability of existing road networks. Positive outcomes have already emerged from these efforts, mostly for the trunk paved networks. However, results have so far been mixed for the unpaved network, whose conditions continue to deteriorate. Mozambique and Uganda are no exception to this trend. Aware of this situation, both governments are implementing, with support from the World Bank, major road rehabilitation programs while searching for appropriate low-cost technologies for LTVRs. At a premium, there are the innovative pavement technologies (IPTs) for sealed roads, which can reduce the capital costs while decreasing the maintenance and rehabilitation burden. If these efforts are successful, LTVRs could be economically sealed at lower traffic levels than was hitherto possible. The Mozambique and Uganda road administrations are using distinct approaches to R&D. Whereas Mozambique has set up a program of trial sections, Uganda is developing pilot demonstration projects to select IPTs. The focus here is on management of the R&D process, on quality enhancement for successful innovation, and on the need for the development of specifications and related methods of construction using nonconventional materials for stabilization and surfacing of low-traffic roads.
Network-Level Application of Roads Economic Decision Model in Nicaragua
Authors: Archondo-Callao Rodrigo , Talavera Douglas Méndez , Zeas Lubina Cantarero
Published: April 2007

A network-level application of the Roads Economic Decision (RED) model in Nicaragua is presented. The RED model was developed by the World Bank to improve the decision-making process for development and maintenance of low-volume roads. The model adopts the consumer surplus approach to estimate transport benefits and is customized to the characteristics of low-volume roads, such as the high uncertainty in the assessment of the model inputs, the difficulties in characterizing the road condition of unpaved roads, and the need for a comprehensive analysis of generated traffic to clearly define all accrued benefits. The network-level application was designed to define a rational maintenance and improvement program for a network of secondary unpaved roads with particular attention to the alternative of improving the network by surfacing roads with concrete blocks and to include in the decision-making process not only economic considerations but also poverty indicators and priorities perceived by local administrators.
Rethinking Traditional Approaches to Low-Volume Road Provision in Developing Countries
Authors: Pinard M. I. , Gourley C. S. , Greening P. A. K.
Published: April 2007

Low-volume roads (LVRs) constitute an integral component of the road system in all developing countries, where their importance extends to all aspects of the social and economic development of rural communities. However, the original documentation relating to the provision of such roads is based in many respects on technology and research carried out in Europe and the United States some 30 to 40 years ago in environments very different from those prevailing in developing countries. As a result, these traditional approaches are often inappropriate for application in developing countries. Moreover, they tend to focus on the technical environment of road provision, with inadequate consideration of other interrelated environments that critically influence the types of LVRs that should be provided. As a result, a need for new, more holistic approaches to low-volume road provision has been engendered to satisfy the various needs of rural communities in a more sustainable manner. The objective of this discussion is to provide an insight into new, more holistic and sustainable approaches to the provision of LVRs in developing countries. Embodied in these new approaches is a need to rethink the old ways of providing such roads based on research and development work that has been carried out in these countries during the past 20 years. Examples include aspects of planning and project appraisal, geometric and pavement design, construction and drainage, and environmental issues, all of which need to be reconsidered in a more appropriate manner.
Nature and Effects of Low-Volume Roads in Botswana
Authors: Madzikigwa Bizzar B.
Published: April 2007

The road sector in Botswana continues to develop its road network throughout the country at a tremendous rate. When Botswana gained independence in 1966, it had only 10 km (16 mi) of bitumen road. By 1992 the total length of bituminous surfaced road reached 3500 km (2,175 mi) out of a total road network of 18 000 km (11,285 mi). These statistics clearly show that the majority of roads are not yet surfaced; these are low-volume roads that provide access to the rural areas where most of the country’s population is found, though in low density. In spite of the rapid improvement in the quality of the national road network in recent years, much remains to be done. In the early 1970s and early 1980s the rural roads unit was introduced in the Ministry of Works Transport and Communications, which was charged with the responsibility of design and construction of low-volume roads around the country in a bid to integrate the country’s road network. This unit was later disbanded in the 1990s, and all roads are improved through the conventional procurement system using private contractors. For these roads the justification of a surfacing project based on conventional economic return methods does not apply, and worse still, the road improvements have to compete with other amenities for the same limited resources. Three ministries in Botswana are responsible for roads: Ministry of Works Transport and Communications, Ministry of Local Government, and Ministry of Trade, Industry, Wildlife and Tourism. These ministries have different responsibilities for different roads within the country, and earth, sand, and gravel roads are found under the jurisdiction of each of the ministries. The major drawbacks concerning low-volume roads in Botswana are inadequate maintenance, poor road construction materials, and the environmental impacts of the roads. Since the budget and resources are inadequate to keep these roads in good condition, it would be prudent to find technological means that would improve the locally available road construction materials so as to minimize their effects on the environment and vehicle operating costs.
Proposed Method to Assess Timber Harvesting Roads
Authors: Dean Darrell R.
Published: April 2007

Timber harvesting roads, skid roads, and truck roads have been identified as major sources of stream sedimentation during logging operations. Researchers have stated that the planning for timber harvesting road networks is key to reducing these erosion and stream sedimentation sources. One impediment to reducing stream sedimentation is that planners do not have a way to quantify road network sufficiency and efficiency, particularly for those networks used by rubber-tired skidders during cable skidding operations. Reach capacity and excess reach capacity are proposed as ways to measure road network sufficiency and efficiency. Reach capacity is defined as the percent of a tract covered by a zone of specified distance around each road segment. Reach capacity is a measure of that portion of the tract that can be reached with a winch cable from the road system to move trees to the road for skidding. Excess reach capacity is the total area of all possible road zone overlaps expressed as a percentage of the reach capacity. Excess reach capacity is a measure of road duplication or the portion of the tract that can be serviced by more than one road. Use of these metrics will provide logging road planners with a tool to compare two or more proposed road network alternatives on a particular logging job, or to assess a completed road network. The Global Positioning System and the geographic information system were used to gather data and perform the spatial analysis necessary to acquire the metrics. A case study illustrates the proposed assessment method.
Establishment of a Road Classification System and Geometric Design and Maintenance Standards for Low-Volume Roads
Authors: Giummarra George J.
Published: April 2007

The primary purpose of a road hierarchy is to ensure that appropriate management, engineering standards, and maintenance practices are applied to a road on the basis of its function. A hierarchy also enables more efficient use of limited resources by allocating funds to those roads that are in greater need and for which the costs are better justified. Studies were recently completed to arrive at a classification system for a wide range of low-volume roads covering rural municipalities and forestry organizations. Results are presented of an extensive literature search and the process and methodology developed to arrive at acceptable standards for various stakeholders relative to a classification system and geometric design and maintenance standards for low-volume roads. Five road classifications are derived for low-volume roads, including functional and road characteristics, to assist in classifying each road in a network. Also included for each road class are guidelines for geometric standards that relate to design speed, cross-sectional elements, and horizontal and vertical curve requirements for flat, hilly, and mountainous terrain. These standards were derived with reference to existing standards, engineering experience, and resources available to a road agency. Each classification has a set of maintenance criteria for both sealed and unsealed roads, covering the key defect types and intervention levels for routine and urgent maintenance.
Innovative and Cost-Effective Solutions for Roads in Rural Areas and Difficult Terrain
Authors: Visser A. T. , Hall Sally
Published: April 2007

In many parts of the world, high-level engineering solutions are inappropriate for rural areas where expertise, skills, and equipment are unavailable. Often these areas suffer from difficult terrain that also makes accessibility a problem. At the 1999 International Conference on Low-Volume Roads, a design catalogue was presented for a flexible portland cement concrete pavement using geocells, which was suitable for labor-intensive construction. However, the catalogue required layer works, which meant that construction equipment, although minimal, was required. This was seen as a major constraint, particularly when communities become involved in the construction of these local access roads. In addition, in difficult terrain the handling of drainage becomes a major engineering undertaking for which expertise may not be locally available. The aim of this study was to develop a structural design catalogue that caters for the range of traffic and material conditions typically encountered in these remote rural areas. Additionally, standard solutions were developed for dealing with steep gradients and surface drainage that are coupled to the structural design. The fundamental engineering principles were used to derive the structural design catalogue and in the management of surface drainage. Case studies were conducted in the successful application of the design catalogue to demonstrate the approach and design procedures. This approach has made a significant contribution in improving the quality of life of rural communities, particularly in remote and often poor regions of South Africa.
Low-Volume Roads Engineering: Best Management Practices
Authors: Keller Gordon , Sherar James
Published: April 2007

The concept and application of best management practices (BMPs) for low-volume roads projects were studied. BMPs are techniques or design practices that will prevent or reduce nonpoint pollution, maintain water quality, and help produce well-built roads. A Low-Volume Roads Engineering Best Management Practices Field Guide was developed to address those key practices. Roads that are not well planned or located, not properly designed or constructed, not well drained, not well maintained, or not made with durable materials often produce negative impacts, most of which are preventable with good engineering and road management practices. A number of key practices and design techniques can be used to prevent adverse impacts on roads. First a road must serve the needs of the user through good transportation system planning. Long-term cost-effectiveness and minimized impacts are then achieved through application of good design and maintenance practices, including a road location that avoids problematic areas such as slides or springs; positive surface drainage; adequately sized and appropriate drainage crossing structures; stable cut and fill slopes; use of erosion control measures; roadway surface stabilization; and materials source development with subsequent site reclamation.
Biodiversity Conservation in Road Projects: Lessons from World Bank Experience in Latin America
Authors: Ledec George , Posas Paula J.
Published: April 2007

The unprecedented and irreversible loss of biodiversity in modern times is caused primarily by the elimination or degradation of natural habitats. Because the construction and improvement of roads sometimes lead, directly or indirectly, to the loss and degradation of natural habitats, road construction and biodiversity aims are often at odds. However, many potentially serious conflicts between road projects and biodiversity conservation can be avoided. Induced negative impacts can be minimized by careful project siting. Where some natural habitat loss is inevitable, appropriate mitigation may include establishment of strict protection zones alongside the road or compensatory protected areas elsewhere. Such mitigation requires effective collaboration, for example, between the agencies responsible for roads and protected areas. Direct adverse impacts of road works on biodiversity also can be significant but are generally simpler to avoid or mitigate because they are more fully under the control of road construction agencies, contractors, and concessionaires. Biodiversity loss and environmental damage can be considerably reduced when planners and road construction agencies site roads adjacent to existing railways, pipelines, or transmission lines; practice sound road engineering; maintain good drainage and natural water flows; minimize roadside habitat loss; and exercise care in the siting and design of borrow pits, construction camps, and other complementary facilities. Environmental rules for contractors, including transparent penalties for noncompliance, need to be incorporated in bidding documents and contracts. Ideally, road projects are designed and implemented so as to avoid or compensate adequately for any adverse impacts on natural habitats and biodiversity. Through mitigation measures, potentially controversial projects can even produce significant net environmental benefits—a win-win outcome.
Use of Native Vegetation and Biostimulants for Controlling Soil Erosion on Steep Terrain
Authors: Brindle Frances A.
Published: April 2007

Native grass species are increasingly requested for use on revegetation and restoration projects following land disturbance. Native species can be slow to establish, a problem when the goals are to obtain quick ground cover to protect against rainfall impact and sheet and rill erosion and to promote root growth to stabilize soil on steep terrain. In addition, disturbed land is subject to invasion by weed species, creating competition with desirable plants for soil nutrients and moisture. Organic soil amendments and soil stabilizers were used on a large restoration project in northwest Oregon to provide soil conditions that would foster a healthy stand of native grasses and forbes (broadleaf plants) while holding the soil in place until plant establishment could occur. Organic soil amendments were prescribed that would improve soil structure, aid nutrient availability, and provide humic acids and bacterial activators. Organic mulch was added to provide the nutrient energy source for soil microorganisms. The amendments were mixed in a slurry and applied in a onestep hydroseeding application during the late fall of 2001. The materials were applied along with the native seed mixture with a mechanically agitated hydroseeding machine and sprayed on the surface in a pressurized spray. The results of the field evaluation were favorable for the ability of the soil to resist water erosion through the initial rainy season and the native species establishment after application.
Natural Systems Approach to Preventing Environmental Harm from Unpaved Roads
Authors: Colbert Woodrow J.
Published: April 2007

In the United States, non-point-source pollution has been documented at more than 11,000 individual sites along the state of Pennsylvania’s 20,000 mi of unpaved roads. This substantiates the fact that traditional road maintenance practices are not addressing dust and sediment pollution. A Dirt and Gravel Road Pollution Prevention Program instigated by concerned citizens, initiated by the Pennsylvania Department of Transportation, and implemented by local county conservation districts has begun implementing an education and funding program that encourages recognition and use of the relentless forces of nature to reduce pollution through enlightened road maintenance objectives and decisions. Referred to as the natural systems approach, this work has application when maintenance decisions are made by nonengineer generalists who can be quickly trained to recognize the indicators of stable vegetation and drainage patterns associated with good and bad road performance. Replicating the stable environments associated with good roads is then a local initiative to treat the problem and not the symptom. Solutions can be accomplished in stages with whatever resources local officials have available. Examples of a few ramifications of traditional decision making together with alternative solutions to them were developed to precipitate discussion. A call has been made to assemble an interdisciplinary task force to further efforts, such as AASHTO’s 2001 Guidelines for Geometric Design of Very Low-Volume Local Roads (ADT < 400), that will relieve pressure on local officials to adhere to traditional decision making, which is based on paved highvolume roads.
Practical Safety Tool for Local Low-Volume Rural Roads: The Road Safety Audit Review
Authors: Wilson Eugene M. , Lipinski Martin E.
Published: April 2007

Practical tools for improving transportation safety are needed worldwide. It has been estimated that motor vehicle–related crashes account for more than 1 million fatalities each year, and the number of serious injuries far exceeds fatalities. Local and low-volume roads are significantly overrepresented in crash statistics. Globally, the road safety audit (RSA) concept has been recognized as an effective tool in identifying and reducing the crash potential of roadways when used to analyze the safety aspects of project plans and designs before completion. In the local rural road arena, many safety issues are associated with existing roadway networks. Many of these networks have developed over time with little or no planning or design. There is a critical need for a practical tool that focuses on the safety of the existing as-built local road network. The RSA review (RSAR) process has been developed for this purpose, giving specific recognition to the functionality of the road being evaluated for safety issues. Significant numbers of safety improvements are needed, and practical approaches to address these needs are crucial. The RSAR tool has the potential to be particularly beneficial to local governments in systematically addressing safety deficiencies on existing rural road networks. In addition, it is a proactive safety tool that has the potential to protect agencies from tort liability since it establishes a record of the organization’s safety agenda. An RSAR methodology that can be adapted by local agencies is presented. A case study illustrating the application of this process is included. Also highlighted is a local rural training program that has been presented in several states for county applications. The focus is on U.S. county applications, but it is recognized that the process has utility for other agencies and has application in other countries. The necessity for training as a key component in the development of a sustainable safety program is emphasized.
Low-Volume Road Flexible Pavement Design with Geogrid-Reinforced Base
Authors: Vischer William
Published: April 2007

Reconstruction of a U.S. Department of Agriculture Forest Service campground facility in the North Dakota National Grasslands required redesign and substantial construction change because of an unstable clay subgrade. The original proposal provided for removing the old asphalt and adding additional base and a new asphalt surface. When the asphalt cement was removed, it was found that the base course had migrated into the clay subgrade, leaving the subgrade unstable. Options explored for redesign were thickened gravel base sections, lime stabilization, and geosynthetic reinforcement. The geogrid-reinforced base was selected. Design analysis consisted of two phases: ( a) bearing capacity analysis for construction traffic and ( b) flexible pavement analysis and design to support long-term recreation traffic. The first involved primarily Tensar design methods; the second, an empirical and mechanistic approach. Empirical methods, based on 1993 AASHTO design procedures, included Tensar methods and the recent Perkins–Michigan Department of Transportation model. The mechanistic approach used the EVERSTRESS and KENLAYER elastic layered programs. All design methods used were found beneficial and are recommended. The final flexible pavement sections constructed were dictated by the construction traffic and consisted of 2 in. of asphalt concrete on a reinforced base course ranging in thickness from 4 to 12 in. The project had to be completed in 3 weeks, so investigation and testing were limited, and the design parameters were based primarily on field dynamic cone penetrometer testing and correlations. Enforcement of the limited wheel loads became a continuous inspection problem. In addition, because of the fineness of the base aggregate produced, a separation geotextile had to be added to preclude migration of the base aggregate through the geogrid into the subgrade.
Rural Intelligent Transportation System Natural-Hazard Management on Low-Volume Roads
Authors: Decker Rand , Rice Robert , Putnam Steve , Singer Stanford
Published: April 2007

The growth of winter travel on alpine roads in the western United States has increased the risk to motorists and highway maintenance personnel owing to a variety of natural hazards. Hazards include snow and ice, avalanching snow, and blowing and drifting snow. The conditions call for attendant need for incident response. A substantial number of affected routes are low-volume rural winter roads. Configurations have been developed for rural intelligent transportation system (ITS) technology that can detect hazards and provide, autonomously and in real time, warnings to and traffic control actions for motorists, highway maintainers, and incident responders for roadway natural hazards. These warnings include on-site traffic control signing and road closure gates, in-vehicle audio alarms for agency maintenance and patrol vehicles, and notification to highway agency maintenance facilities or centralized multiagency dispatchers. These actions and notifications are initiated automatically from the remote rural sites and via manual intervention from off-site personnel, well removed from the rural roadway corridor itself. About 5 years of experience have been accumulated in using these rural ITS natural-hazard reduction systems, including snow avalanche detection and warning systems on Loveland Pass, Colorado; Hoback Canyon, Wyoming; and Banner Summit, Idaho. Automated road closure gates on the Teton Pass in Idaho and Wyoming now allow for remote road closure during heavy snow events. These cost-effective ITS natural-hazard systems are highly exportable for other processes that affect rural low-volume roadways, including landslide, flooding, high surf, high winds, loss of visibility, wildlife, and other natural hazards of this type.
Development of Guidelines for Unsealed Road Assessment
Authors: Jones D. , Paige-Green P. , Sadzik E.
Published: April 2007

The assessment of unsealed roads in South Africa has, up to now, been done on an ad hoc basis with a variety of individual standards and has produced highly subjective results. A standard visual assessment manual has been developed to provide a single, unified objective system of unsealed road evaluation in South Africa and southern Africa. The assessment techniques, as well as standard descriptors of the various distress modes, are clearly defined in the document. Examples of the content and application of the document are provided and discussed.
Evaluation of Cement Kiln Dust-Stabilized Reclaimed Asphalt Pavement Aggregate Systems in Road Bases
Authors: Taha Ramzi
Published: April 2007

Road rehabilitation and reconstruction generate large supplies of reclaimed asphalt pavement (RAP) aggregate, and recycling into asphalt paving mixtures is the predominant application. Cement kiln dust (CKD), also known as cement bypass dust, is a by-product material generated during production of portland cement. In Oman, where recycling of pavement materials is not practiced, a first attempt was made at combining two by-product materials for use in road construction. Conservation of natural resources and preservation of the environment are two benefits that could be gained by reusing waste materials. The potential use in road bases of CKD-stabilized RAP and RAP with virgin aggregate mixtures was investigated. Physical, compaction, and unconfined compressive strength tests were conducted on RAP and virgin aggregate blends of 100% to 0%, 90% to 10%, 80% to 20%, and 0% to 100%. Samples were prepared using CKD at 0%, 3%, 5%, 7%, 10%, 15%, and 20% and were cured for 3, 7, and 28 days in plastic bags at room temperature. Results indicate that the maximum dry density and unconfined compressive strength of RAP generally increase with addition of virgin aggregate and CKD. The moisture content-dry density curves for CKD-stabilized RAP aggregate mixtures did not show a distinctive peak similar to that of the 100% virgin aggregate blend. Longer curing periods will produce higher strength values. CKD content of 15% seems to be the optimum for achieving maximum strength.
Basaltic Crushed Rock Stabilized with Cementitious Additives: Compressive Strength and Stiffness, Drying Shrinkage, and Capillary Flow Characteristics
Authors: Chakrabarti Srijib , Kodikara Jayantha
Published: April 2007

Research was undertaken to increase knowledge of the properties of local stabilized pavement materials to facilitate their wider use in road construction and rehabilitation. Laboratory tests involved testing for the unconfined compressive strength (UCS), shrinkage, and capillary behavior of crushed basaltic rocks stabilized with two conventional cementitious binders—general purpose cement and lime—and two cementitious binders comprising industrial waste products—blended cement and alkali-activated slag. The alkali-activated slag and blended cement significantly increased UCS of untreated material and performed as well as or better than such traditional binders as general purpose cement. Overall, lime performed poorly as a stabilizer of crushed basaltic rocks, primarily because the fine content containing clay minerals was not significant in the crushed basaltic rock composition. UCS of stabilized materials increased significantly as binder content increased; UCS could be described as a function of binder quantity. Ultimate shrinkage increased with binder content for general purpose cement and alkali-activated slag, but for blended cement, behavior was different. The rate of drying shrinkage was relatively high at the early stage of shrinkage. Generally, alkali-activated slag produced less shrinkage compared with general purpose and blended cements. Capillary rise and water absorption were also measured. Test results indicated that the rate of capillary rise and amount of water absorbed by the material matrix decreased with the increase of binder content. The research indicated that the use of binders with industrial by-products could be a viable option in stabilization of crushed basaltic rock materials.
Investigation of Performance of Asphalt Pavement with Fly-Ash Stabilized Cold In-Place Recycled Base Course
Authors: Wen Haifang , Tharaniyil Mathew P. , Ramme Bruce
Published: April 2007

Class C fly ash is a coal combustion product from lignite or subbituminous coal obtained as a result of the power generation process. In recent years, efforts have been made to incorporate self-cementing fly ash into cold in-place recycled (CIR) asphalt material to improve the structural capacity of asphalt pavement base layers. In this study, asphalt pavements in County Trunk Highway JK in Waukesha County, Wisconsin, were pulverized in place and mixed with fly ash and water to function as a base course. To evaluate the contribution of fly ash to the pavement’s structural performance, nondestructive deflection tests were performed with a KUAB 2m-FWD falling weight deflectometer (FWD) on the outer wheelpath right after construction. The MICHBACK program was used to backcalculate the material properties of pavement layers from FWD measurements of deflection. The average moduli of the materials in the hot-mix asphalt layer, fly ash–stabilized base course, and subgrade were backcalculated. The structural capacity and structural number were also obtained from FWD test data. The structural coefficient of 0.16 was obtained for the fly ash–stabilized base course in the highway. The results of FWD testing indicate that CIR stabilization with self-cementing fly ash is an economical method of recycling flexible pavements and eliminates the need for expensive new granular base courses for road reconstruction.