The effect of right-turn-on-red on pedestrian and bicyclist accidents

Right-Turn-on-Red (RTOR), in its “Western” version allows motorists to turn right on a red signal after stopping and yielding, unless specifically prohibited by a sign. The objective of this study was to determine the effect of Western RTOR on pedestrian and bicycle accidents in selected jurisdictions adopting the rule in the mid-1970s. The results showed significant increases in pedestrian and bicyclist accidents involving right-turning vehicles at signalized locations following the introduction of Western RTOR. These increases were: 40 % for pedestrians and 82 % for bicycles in New York State; 107 % for pedestrians and 72 % for bicycles in Wisconsin; 57 % for pedestrians and 80 % for bicycles in Ohio; and 82 % for pedestrians in New Orleans. Analysis of police accident reports suggested that drivers stopped for a red light are looking left for a gap in traffic and do not see pedestrians and bicyclists coming from their right. Countermeasure research and development was recommended to deal with this well defined problem which involves between 1 % and 3 % of all pedestrian and bicycle accidents.     

Objective job conditions,social support and perceived stress among blue collar workers

The hypothesis that perceived supportive relations mediate the association between extra-individual (objective) job conditions and perceptions of occupational stress is tested in a population of blue collar workers. Responses to a mailed questionnaire (N = 1830) include measures of social support from four sources (supervisor, coworkers, spouse, friends/relatives) and measures of perceived stress (five job pressures and four need deprivations). In addition, company records and expert ratings by company, union and study personnel provide measures of objective job conditions which are commensurate with the subjective reports. Associations between objective job conditions and perceived stress are significant but modest in size. Controls for age, education, exposure to noxious agents and physical effort on the job do not alter associations between objective conditions and perceived stress. For five of the nine indicators of perceived stress, social support and objective conditions interact in determining perceptions. This is interpreted as a buffering effect in which social support provides a context that significantly alters perceptions of job conditions. The effect of supervisor support is especially important in regard to buffering. It is suggested that research on the quality of work should be especially aware of the conditional nature of the relationship between objective job conditions and perceptions.     

Natural structure in the man-made environment

Summary The paper contains examples of design elements and natural symmetries that have appeared and are now being used in man-made works. The pleasing principles of symmetric structures have been shown in examples of architectural ornament, planning of towns and university campuses. These same symmetries are shown to give coherence to the growth of forms in nature. The paper further discusses how different artists have arrived at their particular choices of natural symmetries to be used whether in planning, architectural structures, town clusters or painting. Dr Arthur L. Loeb was born in The Netherlands and was educated at the University of Pennsylvania and Harvard University, where he took a doctorate in Chemical Physics. Through his research contact with Gyorgy Kepes, M. C. Escher and R. Buckminster Fuller, he has been able to embrace the whole spectrum of design. He is a sculptor and painter, and has great interest in music. His 40 or so publications show his expertize as well as his exceptional ability in combining the compatible aspects of the arts and the sciences. His present position is Head Tutor at the Department of Visual and Environmental Studies, and Curator of the Teaching Collection in the Carpenter Center, Harvard University.     

FISH RESPONSES TO TEMPERATURE TO ASSESS EFFECTS OF THERMAL DISCHARGE ON BIOLOGICAL INTEGRITY1

ABSTRACT: The applicability of the U.S Environmental Protection Agency's (USEPA) water temperature criteria in evaluating the impact of a thermal discharge from the P. H. Glatfelter Paper Company, Spring Grove, Pennsylvania, is analyzed. A review of the literature relative to 11 temperature Criteria was conducted for six fish species designated by the USEPA as “representative important species” (RIS) of the West Branch Codorus Creek, Susquehanna River drainage. The species were: Notemigonus crysolcucas (golden shiner), Notropis analostanus (satinfin shiner), Rhinichthys atratulus (blacknose dace), Catostomus comme-soni (white sucker), Lepomis gibbosus (pumpkinseed). and Micropterous salmoides (largemouth bass). It was found that by applying only USEPA suggested criteria that a complete evaluation was not satisfactory. Temperature behavior data, specifically preference and avoidance information, coupled with field sampliug was needed to properly assess the effects of the thermal effluent. The final analysis indicated that the thermal discharge of the paper company should have minimal effect on the fish community of Codorus Creek.     

COMPARISON OF METHODS TO ESTIMATE DEEP PERCOLATION RATES1

ABSTRACT: Deep percolation rates are normally estimated from a water balance. Results are presented of a study undertaken to evaluate three alternative methods of estimating percolation below the root zone when knowledge about the history of applied water and evapotranspiration are not available. The alternative methods are: 1) use of Darcy's equation to calculate deep percolation rate; 2) measurement of the soil temperature prof and calculation of the deep percolation rate from the shape of the temperature depth curve; and 3) measurement of the tritium concentration in the soil water and its relationship to the history of the tritium concentration in rainfall. At the principal study site, the Darcy velocity of flow ranged from 9 cm per year determined by the temperature method, to 40 cm per year determined by the tritium method. Darcy's equation to calculate seepage rates resulted in an estimation of deep seepage of 18 cm per year. An average deep percolation rate at the principal study site of 22 cm per year was determined using the average of all three methods. Results for other sites based on the temperature method indicated a lower seepage rate.     

Fitting a Gamma Distribution Over a Synthetic Unit Hydrograph1

ABSTRACT: Several methods for synthetic unit hydrographs are available in the literature. Most of these methods involve the hand fitting of a curve over a set of a few hydrograph points, which can sometimes be a subjective task. Besides, the user often finds it difficult or simply neglects to adjust the generated unit graph to a runoff volume of one unit (inch, cm, or mm). It is the purpose of this paper to present to the design hydrologist a simple method to fit a smooth gamma distribution over a single point specified by the unit hydrograph peak and the time to peak with a guaranteed unit depth of runoff.     

Organizational and Political Considerations in the Municipal Development of Small Hydropower1

ABSTRACT: The potential for hydroelectric power development at existing dams is great in oil dependent New England where there are over 10,000 dams presently in existence. Over 400 developments have been proposed in the region, the majority of which are small scale, and do not have major environmental impacts. Nevertheless, a variety of constraints may hinder development. A study of three efforts by municipalities in unique positions to develop hydropower reveals that organizational and political considerations are significant factors affecting development. Successful hydropower development requires: (1) the cooperation and interaction of citizens, government, and the private sector; (2) community interest and education; and (3) strong resolve.