Evaluating the Impacts of Speed Limit Increases on Rural Two-Lane Highways Using Quantile Regression

Understanding speed selection behavior of drivers following speed limit increases is critically important. To date, the literature has largely focused on freeways and the effects of speed limit changes on two-lane highways remains under researched. Prior research has generally focused on changes to mean speeds, although the speeds of both the highest and lowest drivers are also of great interest. This study investigates trends in free-flow travel speeds following 2017 legislation that increased the posted speed limit from 55 to 65 mph on 943 mi of rural highways in Michigan. Speed data were collected for over 46,000 drivers at 67 increase segments where speed limit increased and 28 control segments where speed limits remained unchanged, before and during each of the two successive years following the speed limit increases. Site-specific traffic, geometric, and cross-sectional information was also collected. Impacts of the speed limit increases on the 15th, 50th, and 85th percentile speeds were evaluated using quantile regression. Separate analyses were conducted for passenger cars and heavy vehicles. Locations where the speed limits were raised experienced increases in travel speeds ranging from 2.8 to 4.8 mph. The control sites experienced marginal changes in speeds, which suggests that any spillover effects of the higher speed limits have been limited. Significant differences were observed across the quantiles with respect to the effects of the speed limit increases, as well as numerous site-specific variables of interest. The results provide important insights about the nature of driver speed selection and the impacts of speed limit increases.

Evaluating the Impacts of Speed Limit Increases on Rural Two-Lane Highways using Quantile Regression

Understanding speed selection behavior of drivers following speed limits increases is critically important. To date, the literature has largely focused on freeways and the effects of speed limit changes on two-lane highways remains under researched. Prior research has generally focused on changes to mean speeds, though the speeds of both the highest and lowest drivers are also of great interest. This study investigates trends in free-flow travel speeds following 2017 legislation that increased the posted speed limit from 55 to 65 mph on 943 miles of rural highways in Michigan. Speed data were collected for over 46,000 drivers at 67 increase segments where speed limit increased and 28 control segments, where speed limits remained unchanged, before and during each of the two successive years following the speed limit increases. Site-specific traffic, geometric, and cross-sectional information was also collected. Impacts of the speed limit increases on the 15th, 50th, and 85th percentile speeds were evaluated using quantile regression. Separate analyses were conducted for passenger cars and heavy vehicles. Locations where the speed limits were raised experienced increases in travel speeds ranging from 3.8 to 5.1 mph. The control sites experienced marginal changes in speeds, which suggests any spillover effects of the higher speed limits have been limited. Significant differences were observed across the quantiles with respect to the effects of the speed limit increases, as well as numerous site-specific variables of interest. The results provide important insights as to the nature of driver speed selection and the impacts of speed limit increases.

Choosing the right approach to green your supply chains

Purpose Due to the different institutional pressure such as those from market, regulations and competitors, companies have implemented green supply chain management (GSCM). Unfortunately, tens of GSCM practices exist. Whether all companies should implement GSCM and how to achieve both environmental and economic performance are still not clear for many companies. The purpose of this paper is to develop models that can be helpful for companies to identify right GSCM practices and implement GSCM effectively and efficiently. Design/methodology/approach Based on about 18 years of study on GSCM with four surveys in China in 2001, 2005, 2012 and 2016, as well as numerous site visits and interviews mainly in China but also in Japan, Germany and Canada, this paper explores institutional drivers as well as opportunities and challenges using theoretical analysis and case studies. GSCM is defined considering a product life cycle. A key three-step GSCM approach is theoretically developed considering opportunities and challenges through life cycle analysis (LCA) of a product and position of a company. Findings All companies should implement GSCM practices to avoid risks. To effectively implement GSCM practices, a company should understand the life cycle of its product and its position in the supply chain. A key three-step LCA-based approach can help companies to identify the critical GSCM practices. Originality/value A key three-step LCA-based approach for GSCM implementation is originally developed based on theoretical analysis and eight years of study.

Tropicana Garage Collapse

<p>In 2003, a major collapse occurred during construction of a parking garage at the Tropicana Hotel in Atlantic City, New Jersey. It resulted in four fatalities, dozens of injured workers, and significant delays to the construction project. The legal matter was eventually settled out of court, reportedly for $100 million US dollars.</p><p>The author led the structural investigation into the collapse on behalf of the General Contractor. The investigation included numerous site visits, preservation of structural evidence, review of design drawings and contractor’s shop drawings, structural analyses, and litigation support.</p><p>The concrete parking garage was being constructed with a proprietary structural floor system, which involved “stay‐in‐place” precast concrete forms that became composite with the cast‐in‐place concrete slabs and wide beams.</p><p>The investigation presented significant challenges due to the intertwined design responsibilities for the system, the difficulty of preserving perishable evidence during the demolition of the unstable structure, the high‐profile nature of the collapse, and the diverse interests of the many involved parties.</p><p>The matter settled out of court, so the results of technical investigations and the lessons learned have not been widely disseminated previously.</p><p>This paper will describe the engineering investigation and findings, discuss the roles and responsibilities of the designers and others, and present recommendations to reduce future failures of similarly organized projects.</p>

Jonson's Acoustic-Oriented Dramaturgy in the First Folio Playtexts of Epicoene and The Alchemist

One significant yet understudied aspect of the First Folio printings of Epicoene and The Alchemist is that their marginal stage directions highlight the importance of Jonson's acoustic-oriented dramaturgy to both plays. In light of Jonson's recurrent associations between exposure to noise pollution and the threat of plague, this essay reads Jonson's acoustic-oriented dramaturgy in Epicoene and The Alchemist as a direct engagement with the contemporary plague-time performance settings of both plays. Moreover, when considered alongside the numerous site-specific engagements of both printed playtexts, what becomes clear is that Jonson's acoustic-oriented dramaturgy assumes an important satirical dimension directed at these plays’ earliest London audiences. First, in part through his acoustic manipulation of the indoor performance environments of the Whitefriars and Blackfriars theaters, Jonson satirically critiques the fantasies of social exclusivity embodied by Morose and Lovewit. Equally importantly, by drawing dramaturgical inspiration from the ambivalent experience of playgoing during an ongoing plague outbreak, Jonson also critiques the fantasies of social exclusivity evident among his plague-time comedies’ well-to-do London audiences.

Mining, Community, and Environment

The previous chapters in this book have reviewed the extensive research carried out on prehistoric copper mines in Europe. Numerous site investigations provide detailed information on the geological setting of these mines and the types of ore minerals extracted. The same studies yield important insights into methods of rock extraction, ore beneficiation, and smelting, and the overall organization of those activities. Building on this solid base of information, it is possible to move beyond an understanding of mining as a technological process to an emphasis on the prehistoric communities involved. The technical details and logistics of the mining process continue to be important, but are now considered as part of a socially informed chaîne opératoire of early metal production. Mining in the modern era is regarded as an economic activity; however, there is also a distinctive character to the individuals and communities who engage in that work. This is also true of prehistoric mining, which was undertaken within specific historical contexts that were structured by particular sets of cultural values. It was a highly social activity, involving closely-knit groups of individuals working together towards a common purpose, in situations where they depended on each other for their safety. With no written records, the challenge for researchers is to understand these social dynamics using material correlates available in the archaeological record. As in other areas of prehistory, there are certain limits to the inferences that can be made using this type of evidence. That said, the significance of metal to later prehistoric societies provides a broad indication of the importance of mining as an activity. A concern with the social background of these miners goes back to the earliest research in this field. The gradual move towards a ‘social archaeology’ of early copper mining reflects broader paradigm shifts in modern archaeology, away from culture historical explanations to more interpretative understandings of the material record. While recognizing the dangers of cross-cultural generalization, ethnohistoric studies serve to illustrate the vivid social history of mining communities.

Alaskan Pottery: A Classification and Historical Reconstruction

Alaskan Pottery has received for the most part somewhat cursory treatment in archaeological reports, and consequently it is often difficult to obtain from published studies data on such basic characteristics as temper, paste, and in some cases, design. Outstanding exceptions to this general tendency are the works of Collins (1937) and de Laguna (1939, 1940, 1947). De Laguna, especially, not only has thoroughly reported upon excavated material but has published information on pottery from many museum collections. Since the publication of de Laguna's penetrating analyses, there have been numerous site reports in which new pottery types were added and old ones partially clarified (Larsen and Rainey 1948; Heizer 1949; Giddings 1949,1952; Oswalt 1952a, 1953a, b, c; Griffin 1953). A systematic approach to Alaskan pottery is needed now to arrange the chronological and geographical positions of various styles and facilitate reference to specific types.

Attributes and the Discovery of Projectile Point Types: With Data from the Columbia-Fraser Region

The Classification of pottery types has apparently already reached a satisfactory degree of descriptive accuracy. Although problems remain, numerous site comparisons and important cultural connections have been based upon pottery. Classification of stone artifacts is not in so happy a state. Wheat has also recently called attention to this fact (1953, p. 196): “If cultures predominantly lithic in complexion are to be correlated satisfactorily with each other … we must pay the same attention to artifacts of stone, bone, shell, etc., that has yielded such valuable results in the study of pottery.” Considerable difficulties are inherent in the classification of stone implements but close inspection shows that these are further increased by a terminology which occasionally serves as much to confuse the picture as to clarify it. Such phrases as “leaf-shaped” or “triangular” blades are common in archaeological literature. Yet the descriptive accuracy of these terms rests upon a meaningful and generally accepted contrast between leaf-shaped and triangular which is not substantiated by the inquiry into their use as presented below.