The effectiveness of safety countermeasures in New York City
Item
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Title
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The effectiveness of safety countermeasures in New York City
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Identifier
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d_2009_2013:cdff4645e0cc:11293
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identifier
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11734
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Creator
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Chen, Li,
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Contributor
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Robert E. Paaswell
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Date
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2012
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Language
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English
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Publisher
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City University of New York.
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Subject
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Civil engineering | Transportation | Public health | Before-After Study | Comparison Group | Safety Countermeasures | Traffic Safety
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Abstract
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The evaluation of the effectiveness of safety countermeasures is very important in urban transportation planning to build safe and livable communities for all residents. Over the last decade, New York City has achieved great reductions in traffic fatalities and crashes by installing safety countermeasures throughout the city. However, the effectiveness of many of the safety countermeasures remains unclear, which is, to a large extent, due to the lack of a rigorous study design and inadequate attention paid to built-environment factors. The objectives of this dissertation are: 1) to develop a safety framework for better understanding and implementing different safety countermeasures; 2) to develop and apply a rigorous study design and methodology in the evaluation of safety countermeasures; 3) to evaluate the safety countermeasures by controlling the effects of the build environment factors on traffic crashes; and 4) to make policy recommendations on the selection and implementation of various safety countermeasures to improve the safety of all road users. A rigorous quasi-experimental design, that is, a before-after analysis with a comparison group, followed by regression models using the Generalized Estimating Equations (GEE) methodology is used to evaluate the effectiveness of safety countermeasures for the safety of various road users, including motorists (e.g., left-turn signal phasing), bicyclists (e.g., bike lanes), and pedestrians (e.g., increasing cycle length, Barnes Dance, split phase timing, signal installation, and high visibility crosswalk). The study shows that: 1) the change of permissive left-turn signal phasing to protected/permissive or protected-only signal phasing does not result in a significant reduction in intersection crashes, and the reduction of left-turn crashes by the protect-only signal phasing is offset by a possible increase in over-taking crashes; 2) the installation of bike lanes does not result in an increase in crashes, despite a likely increase in the number of bicyclists after installation of bike lanes; and 3) the four signal-related countermeasures are found to be more effective in reducing crashes than high visibility crosswalks. Based on the safety framework and the evaluation results, recommendations are proposed for transportation planners and policy makers in the practice of improving traffic safety in large urban area.
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Type
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dissertation
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Source
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2009_2013.csv
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degree
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Ph.D.
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Program
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Engineering
