Equivalent Axleloads for Pavement Design

Proper structural design of highway pavements requires an evaluation of the destructive effects of the anticipated vehicular loading. The concept of load equivalency provides a means for expressing these destructive effects in terms of a single measure, the equivalent axleloads (EAL\u27s). The design EAL\u27s represents the equivalent number of applications of a standard or base axleload anticipated during the design life

Evidence of long distance airborne transport of porcine reproductive and respiratory syndrome virus and Mycoplasma hyopneumoniae

The ability of porcine reproductive and respiratory syndrome virus (PRRSV) and Mycoplasma hyopneumoniae to be transported over long distances via the airborne route was evaluated. A source population of 300 grow-finish pigs was experimentally inoculated with PRRSV MN-184 and M. hyopneumoniae 232 and over a 50-day period, air samples were collected at designated distances from the source herd using a liquid cyclonic collector. Samples were tested for the presence of PRRSV RNA and M. hyopneumoniae DNA by PCR and if positive, further characterized. Of the 306 samples collected, 4 (1.3%) were positive for PRRSV RNA and 6 (1.9%) were positive for M. hyopneumoniae DNA. The PRRSV-positive samples were recovered 4.7 km to the northwest (NW) of the source population. Four of the M. hyopneumoniae-positive samples were obtained at the NW sampling point; 2 samples at approximately 2.3 km and the other 2 samples approximately 4.7 km from the source population. Of the remaining 2 samples, one sample was obtained at the southeast sampling point and the other at the southwest sampling point, with both locations being approximately 4.7 km from the source. The four PRRSV-positive samples contained infectious virus and were ≥ 98.8% homologous to the MN-184 isolate used to inoculate the source population. All 6 of the M. hyopneumoniae-positive samples were 99.9% homologous to M. hyopneumoniae 232. These results support the hypothesis that long distance airborne transport of these important swine pathogens can occur

Characteristics of Outdoor Recreational Travel

The purpose of this investigation was to examine the characteristics of travel to outdoor recreational areas in Kentucky. Data were obtained by means of a license-plate, origin-destination survey at 160 sites within 42 recreational areas and by means of a continuous vehicle counting program at eight of these sites. A computer algorithm was developed for error detection and subsequent adjustment of the volume data as necessitated by occasional malfunction of the traffic recorders and vandalism. Vehicle occupancy was found to depend of the type of recreational area, distance traveled, and vehicle type. Occupancy increased with increasing distance and was greatest for those vehicles pulling camping trailers. Percentages of the various vehicle types were also influenced by the type of recreational area and the distance traveled. The proportion of camping units in the traffic stream increased with increasing distance of travel. In general, trip lengths were quite short as evidenced by the fact that 60 percent of all vehicles traveled less than 50 miles. However, trip-length distribution was highly dependent of the type and location of the recreational area. Analysis of the distribution of traffic over time verified that recreational travel is much more highly peaked than other forms of highway travel and, with the exception of holidays, is concentrated on Sundays during the spring and summer months. This time period appears most appropriate for the design of highways and parking facilities to serve recreational areas. It is highly recommended that future data collection programs be concentrated on the average summer Sunday to enable collection of the maximum amount of usable traffic data with a minimum of effort. Much of the data reported herein can be used in initial efforts to characterize travel to similar types of recreational areas outside of Kentucky

Replacement of a Major Ventilation Raise at the Homestake Gold Mine

Few tasks are more important to the Ventilation Engineer than planning major airways. This paper presents a case study of the inception, design, installation, cost and performance of a 253 m long, 4.27 m diameter subsurface replacement exhaust raise and its connecting drifts. The original raise served as a component of the primary exhaustway (140 m3/s) and heat rejection sink (8MW) for the deepest production district, responsible for 45% of the mine\u27s total ounce production. The chronology of ground control problems with the original raise and attempts to halt the unraveling are described. Planning for a replacement raise commenced once it was realized that the original raise could not be saved. Computer simulation helped size the new raise and connecting drifts. Selection of the raise location was based on a careful rock mechanics assessment. A temporary ventilation bypass system was designed to minimize production loss in event of a catastrophic failure of the old raise while the new raise was being bored. This failure occurred shortly after the temporary bypass was ready. The new raise system was completed in February 1995 at a cost of $US 1.475 million. The troubles encountered, resistance measurements, and final costs are given, and a comparison of planned and actual performance is made

Identification of Hazardous Rural Highway Locations

An effective procedure was determined for identifying hazardous rural highway locations based on accident statistics. Multiple indicators of accident experience that are necessary include the number of fatal accidents, the total number of accidents, the number of effective-property-damage-only accidents, and the accident rate. Critical levels of these four indicators should vary from state to state depending on the nature of the local safety improvement program as well as local traffic and roadway conditions and prevailing attitudes toward highway safety. Specific recommendations are given for use in Kentucky. Critical accident rates are established using quality control procedures. To identify hazardous highway locations, it is necessary to distinguish between short highway segments (spots) and large segments (sections) and to further classify spots as intersection and non-intersection locations. Intersection spots should include a distance of 0.15 mile (0.24 km) along all approaches; non-intersection spots should be 0.3-mile (0.48-km), floating segments; and sections should be 3-mile (4.8-km), floating segments. Both spots and sections should be classified by highway type and location. The use of dual time intervals of 1 and 2 years for accumulating and evaluating accident statistics was found to be desirable

A High-Accident Spot-Improvement Program

As a result of an extensive before-and-after accident study, the high-accident location, spot-improvement program in Kentucky, although not a costly program, was found to have significantly decreased the number of motor vehicle accidents. Favorable benefit-cost ratios indicated that the cost of the program has represented a good investment in comparison with the resultant savings in accident costs. The spot-improvement program had little effect on average accident severity as measured by a severity index. Detailed analysis of available accident data showed that, for studies of the type reported, the 12-month period immediately prior to the date of identification of a high-accident location is not a reliable period for representing the actual long-term before accident experience. A much more acceptable period is the 12 months beginning 2 years in advance of the date of identification. Further analysis also showed that a route segment of 0.1 mile (0.16 km) is not of sufficient length for properly identifying high-accident locations or for accumulating accident statistics to support a before-and-after study. Since only slightly more than five percent of the identified high-accident locations were judged to warrant improvement, the procedure used in Kentucky for identifying high-accident locations, namely, those having three or more accidents at a 0.1-mile (0.16-km) location during a 12-month period, was found to be inefficient

The New Economics of Livestock Production Management

The importance of heterogeneity of animal attributes in livestock production is assessed. Preliminary results indicate that variance and skew measures of attributes may be becoming more important over time.livestock economics, herd management, livestock marketing, Livestock Production/Industries, Marketing,

Thirsty for Justice: A People's Blueprint for California Water

The report's first chapter analyzes the origins of environmental discrimination in California water policy. After an overview of how low income communities and communities of color have been historically left out of California water management, we analyze political, economic and social trends that produce the current exclusionary system and emerging policies and technologies that could further harm low-income communities and communities of color.In the second chapter, we provide an overview of what we term "water governance": who controls water supply and quality and what agencies are responsible for ensuring that people have enough clean water. We explain the current system of water governance, examine changing patterns in control over water, and provide examples of communities that face profound barriers to participating in water decisions. We conclude by discussing barriers within water regulatory entities that prevent community voices from entering into water decision-making.In the third chapter, we provide a picture of water-related environmental injustices that low-income communities and communities of color face on a daily basis. These communities' lack of access to safe, affordable drinking water and healthy watersheds exemplifies the health burdens many communities bear as a result of California's water policies.Our report concludes with policy recommendations for how to remedy some of the most pressing water concerns low-income communities and communities of color face, in order to guarantee the basic right to safe and affordable water

Models of Outdoor Recreational Travel

The purpose of this investigation was to evaluate models of travel flow from population centers throughout the United States to outdoor recreational areas in Kentucky. Data were obtained by means of a license-plate, origin-destination survey at 160 sites within 42 recreational areas and by means of a continuous vehicle counting program at eight of these sites. Attempts to simulate distributed travel flows concentrated on various single-equation models, a cross-classification model, and gravity and intervening opportunities models. The cross-classification model was found to be an acceptable means for simulating and predicting outdoor recreational travel flows and was decidedly superior to the other models. From the cross-classification model, per capita distributed flows were found to (1) decrease at a decreasing rate with increasing population of the origin zone, (2) increase at a variable rate with increasing attraction of tbe recreational area, and (3) decrease at a decreasing rate with increasing distance. The intervening opportunities model was found to be unacceptable as a distribution model since it could not effectively accommodate the widely differing sizes of the 42 recreational areas. The gravity model, on the other hand, was quite effective in distributing actual productions and attractions. Problems associated with tbe gravity model were limited to difficulties in accurately estimating trip productions and attractions in the trip generation phase of analysis

Automated Data Acquisition for Low-Volume Road Inventory and Management

Local governments need suitable inventories and condition surveys to accurately determine and prioritize their funding needs. An efficient method of performing an inventory of the roads and subsequently determining the condition of major system components is to use an automated data-acquisition system to measure and record essential data. The data may be collected and processed by a central inventory management group. The inventory should include pavement characteristics, roadway geometries, and roadside features. Pavement condition may include structural integrity, road roughness, and skid resistance. Roadway geometries include horizontal curvature, length, width, superelevation, and grade. Roadside features include signing, intersections, guardrails, and obstacles. This paper presents a concept for a second-generation vehicle-mounted photologging system that may, in a single-pass, photolog the roadway and automatically record measurements necessary for inventoring and rating. Also, major functions of a central inventory management group are described