Right-turn Traffic Volume Adjustment in Traffic Signal Warrant Analysis

An intersection with heavy right-turn volumes, without any reduction, might mislead a signal warrant analysis, and a different conclusion may be reached on whether a signal is warranted. Previous right-turn volume reduction methods based mostly on engineering judgment lack specific theoretical backgrounds. Therefore, this paper proposes a new method with theoretical justification. The method focuses on traffic operation principles centered on finding the delay equivalent relationship between right-turn and through traffic, that is, to equate the right-turn volume to through vehicles to produce the same control delay on a minor street. Equivalent factor tables were constructed on the basis of four geometric configurations. Combining with the various traffic volume distributions, more than 12,000 scenarios were analyzed. The volume ratio in the two directions of the main street was especially considered. The analysis showed that the uneven volume distribution in the main street had a greater effect on the minor-street right-turn movement. To use the equivalent factors efficiently, statistical regression models were developed. Last, the proposed method was applied to one signal warrant case and demonstrated promising results for its practical application in traffic signal warrant analysis

A systematic assessment of road pavement sustainability through a review of rating tools

Pavements are engineered systems present in every modern society, and they have significant environmental, economic and social impacts. In an effort to promote more sustainable decisions regarding pavement design, construction and management, several pavement sustainability assessment tools have been developed. This research reviewed some of these tools and found that many of them do not treat the pavement as a system; instead, they seek to optimize individual aspects of the pavement in an effort to increase its sustainability. Therefore, a framework for analytically assessing the system outcomes towards sustainable objectives is presented and applied for modern pavement sustainability assessment. The results suggest that this framework provides a way to systematically include data in the evaluation of the outcomes of pavement management decisions towards achieving sustainable objectives

Performance-Based Seismic Design and Assessment of Bridges

Current trends in the seismic design and assessment of bridges are discussed, with emphasis on two procedures that merit some particular attention, displacement-based procedures and deformation-based procedures. The available performance-based methods for bridges are critically reviewed and a number of critical issues are identified, which arise in all procedures. Then two recently proposed methods are presented in some detail, one based on the direct displacement-based design approach, using equivalent elastic analysis and properly reduced displacement spectra, and one based on the deformation-based approach, which involves a type of partially inelastic response-history analysis for a set of ground motions and wherein pier ductility is included as a design parameter, along with displacement criteria. The current trends in seismic assessment of bridges are then summarised and the more rigorous assessment procedure, i.e. nonlinear dynamic response-history analysis, is used to assess the performance of bridges designed to the previously described procedures. Finally some comments are offered on the feasibility of including such methods in the new generation of bridge codes

The mortality impact of bicycle paths and lanes related to physical activity, air pollution exposure and road safety

© 2015 Elsevier Ltd. Objective: Guidelines for bicycle infrastructure design tend to consider safety issues but not wider health issues. This paper explores the overall health impact of bicycle infrastructure provision, including not just road safety impacts, but also the population health impacts stemming from physical activity as well as cyclists' exposure to air pollution. Data and methods: We have summarised key publications on how bicycle paths and lanes affect cyclists' exposure to physical activity, air pollution, and road safety. The health impact is modelled using all-cause mortality as a metric for a scenario with new bicycle lanes and paths in a hypothetical city. Results: The outcomes of the study suggest that, based on currently available research, a reduction of all-cause mortality is to be expected from building bicycle lanes and paths along busy roads with mixed traffic. Increased physical activity through more time spent cycling is the major contribution, but is also the most uncertain aspect. Effects related to air pollution and cycling safety are likely to reduce mortality but are small. The overall benefits are large enough to achieve a high benefit-cost ratio for bicycle infrastructure. Conclusions: The introduction of bicycle paths and lanes is likely to be associated with health benefits, primarily due to increased physical activity. More research is needed to estimate the absolute size of the health benefits. In particular, evaluations of the effects of bicycle infrastructure on time spent cycling are limited or of insufficient quality to infer causality. We recommend before-after studies measuring the effects of different interventions and in areas representing a wide range of base levels of cycling participation

Analysis of long-term observations of NOx and CO in megacities and application to constraining emissions inventories

Long-term atmospheric NOx/CO enhancement ratios in megacities provide evaluations of emission inventories. A fuel-based emission inventory approach that diverges from conventional bottom-up inventory methods explains 1970–2015 trends in NOx/CO enhancement ratios in Los Angeles. Combining this comparison with similar measurements in other U.S. cities demonstrates that motor vehicle emissions controls were largely responsible for U.S. urban NOx/CO trends in the past half century. Differing NOx/CO enhancement ratio trends in U.S. and European cities over the past 25 years highlights alternative strategies for mitigating transportation emissions, reflecting Europe's increased use of light-duty diesel vehicles and correspondingly slower decreases in NOx emissions compared to the U.S. A global inventory widely used by global chemistry models fails to capture these long-term trends and regional differences in U.S. and Europe megacity NOx/CO enhancement ratios, possibly contributing to these models' inability to accurately reproduce observed long-term changes in tropospheric ozone

Chapter 19 Noise pollution and its impact on human health and the environment

This chapter deals with (1) the basic theory of sound propagation; (2) an overview of noise pollution problem in view of policy and standards by the World Health Organization, the United States, and the European Union; (3) noise exposure sources from aircraft, road traffic and railways, in-vehicle, work, and construction sites, and occupations, and households; (4) the noise pollution impact on human health and the biological environment; (5) modeling of regional noise-affected habitats in protected and unprotected land areas and the marine environment; (6) noise control measures and sustainability in view of sustainable building design, noise mapping, and control measures such as barriers and berms along roadsides, acoustic building materials, roadway vehicle noise source control, road surface, and pavement materials; and (7) environmental noise pollution management measures and their impact on human health