Sun, Feiyang; Chen, Peng; Jiao, Junfeng. (2018). Promoting Public Bike-Sharing: A Lesson from the Unsuccessful Pronto System. Transportation Research: Part D, 63, 533 – 547.
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Abstract
In 2014, Seattle implemented its own bike-sharing system, Pronto. However, the system ultimately ceased operation three years later on March 17th, 2017. To learn from this failure, this paper seeks to understand factors that encourage, or discourage, bike-sharing trip generation and attraction at the station level. This paper investigates the effects of land use, roadway design, elevation, bus trips, weather, and temporal factors on three-hour long bike pickups and returns at each docking station. To address temporal autocorrelations and the nonlinear seasonality, the paper implements a generalized additive mixed model (GAMM) that incorporates the joint effects of a time metric and time-varying variables. The paper estimates models on total counts of pickups and returns, as well as pickups categorized by user types and by location. The results clarify that effects of hilly terrain and the rainy weather, two commonly perceived contributors to the failure. Additionally, results suggest that users in the University District, presumably mostly university students, tend to use shared bikes in neighborhoods with a higher household density and a higher percentage of residential land use, and make bike-sharing trips regardless workdays or non-workdays. The paper also contributes to the discussion on the relationship between public transportation service and bike-sharing. In general, users tend to use bike-sharing more at stations that have more scheduled bus trips nearby. However, some bike-sharing users may shift to bus services during peak hours and rainy weather. Several strategies are proposed accordingly to increase bike ridership in the future.
Keywords
Bicycle Sharing Programs; Urban Transportation; Transportation & The Environment; Land Use Planning; Time-varying Systems; Bike-sharing; Built Environment; Generalized Additive Mixed Model; Pronto; Temporal Factors; Built Environment Factors; Bicycle; Impact; Transportation; Walking; Usage
Chen, Peng; Shen, Qing. (2019). Identifying High-risk Built Environments for Severe Bicycling Injuries. Journal of Safety Research, 68, 1 – 7.
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Abstract
Introduction: This study is aimed at filling part of the knowledge gap on bicycling safety in the built environment by addressing two questions. First, are built environment features and bicyclist injury severity correlated; and if so, what built environment factors most significantly relate to severe bicyclist injuries? Second, are the identified associations varied substantially among cities with different levels of bicycling and different built environments? Methods: The generalized ordered logit model is employed to examine the relationship between built environment features and bicyclist injury severity. Results: Bicyclist injury severity is coded into four types, including no injury (NI), possible injury (PI), evident injury (El), and severe injury and fatality (SIF). The findings include: (a) higher percentages of residential land and green space, and office or mixed use land are correlated with lower probabilities of El and SIF; (b) land use mixture is negatively correlated with El and SIF; (c) steep slopes are positively associated with bicyclist injury severity; (d) in areas with more transit routes, bicyclist injury is less likely to be severe; (e) a higher speed limit is more likely to correlate with SIF; and (f) wearing a helmet is negatively associated with SIF, but positively related to PI and El. Practical applications: To improve bicycle safety, urban planners and policymakers should encourage mixed land use, promote dense street networks, place new bike lanes in residential neighborhoods and green spaces, and office districts, while avoiding steep slopes. To promote bicycling, a process of evaluating the risk of bicyclists involving severe injuries in the local environment should be implemented before encouraging bicycle activities. (C) 2018 National Safety Council and Elsevier Ltd. All rights reserved.
Keywords
Motor Vehicle; Land-use; Crashes; Severities; Facilities; Frameworks; Frequency; Cyclists; Bike; Bicyclist Injury Severity; Built Environments; Generalized Ordered Logit Model; Us Cities; Bicycles; Urban Environments; Injuries; Neighborhoods; Land Use; Urban Areas; Paths; Protective Equipment; Bicycling; Fatalities; Correlation; Residential Areas; Traffic Accidents & Safety; Safety; Logit Models; Ecological Risk Assessment; Slopes; Health Risks; Urban Transportation; Studies; Environments
Kang, Mingyu; Moudon, Anne Vernez; Kim, Haena; Boyle, Linda Ng. (2019). Intersections and Non-Intersections: A Protocol for Identifying Pedestrian Crash Risk Locations in GIS. International Journal Of Environmental Research And Public Health, 16(19).
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Abstract
Intersection and non-intersection locations are commonly used as spatial units of analysis for modeling pedestrian crashes. While both location types have been previously studied, comparing results is difficult given the different data and methods used to identify crash-risk locations. In this study, a systematic and replicable protocol was developed in GIS (Geographic Information System) to create a consistent spatial unit of analysis for use in pedestrian crash modelling. Four publicly accessible datasets were used to identify unique intersection and non-intersection locations: Roadway intersection points, roadway lanes, legal speed limits, and pedestrian crash records. Two algorithms were developed and tested using five search radii (ranging from 20 to 100 m) to assess the protocol reliability. The algorithms, which were designed to identify crash-risk locations at intersection and non-intersection areas detected 87.2% of the pedestrian crash locations (r: 20 m). Agreement rates between algorithm results and the crash data were 94.1% for intersection and 98.0% for non-intersection locations, respectively. The buffer size of 20 m generally showed the highest performance in the analyses. The present protocol offered an efficient and reliable method to create spatial analysis units for pedestrian crash modeling. It provided researchers a cost-effective method to identify unique intersection and non-intersection locations. Additional search radii should be tested in future studies to refine the capture of crash-risk locations.
Keywords
Traffic Crash; Walking; Collisions; Accidents; Models; Pedestrian Safety; Spatial Autocorrelation; Algorithm
Rodriguez, Barbara X.; Simonen, Kathrina; Huang, Monica; De Wolf, Catherine. (2019). A Taxonomy for Whole Building Life Cycle Assessment (WBLCA). Smart And Sustainable Built Environment, 8(3), 190 – 205.
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Abstract
Purpose The purpose of this paper is to present an analysis of common parameters in existing tools that provide guidance to carry out Whole Building Life Cycle Assessment (WBLCA) and proposes a new taxonomy, a catalogue of parameters, for the definition of the goal and scope (G&S) in WBLCA. Design/methodology/approach A content analysis approach is used to identify, code and analyze parameters in existing WBLCA tools. Finally, a catalogue of parameters is organized into a new taxonomy. Findings In total, 650 distinct parameter names related to the definition of G&S from 16 WBLCAs tools available in North America, Europe and Australia are identified. Building on the analysis of existing taxonomies, a new taxonomy of 54 parameters is proposed in order to describe the G&S of WBLCA. Research limitations/implications The analysis of parameters in WBLCA tools does not include Green Building Rating Systems and is only limited to tools available in English. Practical implications This research is crucial in life cycle assessment (LCA) method harmonization and to serve as a stepping stone to the identification and categorization of parameters that could contribute to WBLCA comparison necessary to meet current global carbon goals. Social implications The proposed taxonomy enables architecture, engineering and construction practitioners to contribute to current WBLCA practice. Originality/value A study of common parameters in existing tools contributes to identifying the type of data that is required to describe buildings and contribute to build a standardized framework for LCA reporting, which would facilitate consistency across future studies and can serve as a checklist for practitioners when conducting the G&S stage of WBLCA.
Keywords
Content Analysis; Taxonomy; Lca; Lca Tools; Tools For Practitioners; Whole Building Life Cycle Assessment
Abramson, Daniel B. (2020). Ancient and Current Resilience in the Chengdu Plain: Agropolitan Development Re-‘Revisited’. Urban Studies (sage Publications, Ltd.), 57(7), 1372 – 1397.
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Abstract
The Dujiangyan irrigation system, China's largest, is one of the world's most important examples of sustainable agropolitan development, maintained by a relatively decentralised system of governance that minimises bureaucratic oversight and depends on significant local autonomy at many scales down to the household. At its historic core in the Chengdu Plain, the system has supported over 2000 years of near-continuously stable urban culture, as well as some of the world's highest sustained long-term per-hectare productivity and diversity of grain and other crops, especially considering its high population density, forest cover, general biodiversity and flood management success. During the past decade, rapid urban expansion has turned the Chengdu Plain from a net grain exporter into a grain importer, and has radically transformed its productive functioning and distinctive scattered settlement pattern, reorganising much of the landscape into larger, corporately-managed farms, and more concentrated and infrastructure-intensive settlements of non-farming as well as farming households. Community-scale case studies of spatial-morphological and household socio-economic variants on the regional trend help to articulate what is at stake. Neither market-driven 'laissez-faire' rural development nor local state-driven spatial settlement consolidation and corporatisation of production seem to correlate well with important factors of resilience: landscape heterogeneity; crop diversity and food production; permaculture; and flexibility in household independence and choice of livelihood. Management of the irrigation system should be linked to community-based agricultural landscape preservation and productive dwelling, as sources of adaptive capacity crucial to the social-ecological resilience of the city-region, the nation and perhaps all humanity.
Keywords
Urbanization; Economies Of Agglomeration; Agricultural Ecology; Sustainability; Urban Planning; Land Use; China; Agglomeration/urbanisation; Agroecosystems; Environment/sustainability; History/heritage/memory; Redevelopment/regeneration; Cultivated Land; Countryside; Expansion; State; Rise; Modernization; Conservation; Integration; Earthquake; Agglomeration; Urbanisation; Environment; History; Heritage; Memory; Redevelopment; Regeneration; Population Density; Production; Farming; Agriculture; Decentralization; Autonomy; Food Production; Households; Landscape; Resilience; Rural Development; Food; Farms; Regional Development; Productivity; Economic Development; Case Studies; Agricultural Production; Biodiversity; Sustainable Development; Governance; Preservation; Crops; Flood Management; Irrigation; Permaculture; Radicalism; Socioeconomic Factors; Grain; Flexibility; Heterogeneity; Variants; Urban Areas; Irrigation Systems; Rural Communities; Bureaucracy; Landscape Preservation; Agricultural Land; Flood Control; Density; Infrastructure; Urban Sprawl; Livelihood; Farm Management; Rural Areas; Urban Farming; Settlement Patterns; Agribusiness; Market Economies
Habibnezhad, Mahmoud; Puckett, Jay; Jebelli, Houtan; Karji, Ali; Fardhosseini, Mohammad Sadra; Asadi, Somayeh. (2020). Neurophysiological Testing for Assessing Construction Workers’ Task Performance at Virtual Height. Automation In Construction, 113.
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Abstract
Falling from heights is the primary cause of death and injuries at construction sites. As loss of balance has a fundamental effect on falling, it is important to understand postural regulation behavior during construction tasks at heights, especially those that require precise focus in an upright standing position (therefore, a dual-task demand on focus). Previous studies examined body sway during a quiet stance and dual tasks to understand latent factors affecting postural balance. Despite the success of these studies in discovering underlying factors, they lack a comprehensive analysis of a task's simultaneous cognitive load, postural sway, and visual depth. To address this limitation, this paper aims to examine construction workers' postural stability and task performance during the execution of visual construction tasks while standing upright on elevated platforms. To that end, two non-intrusive neurophysiological tests, a hand-steadiness task (HST) and a pursuit task (PT), were developed for construction tasks in a virtual environment (VE) as performance-based means to assess the cognitive function of workers at height. Workers' postural stability was measured by recording the mapped position of the Center of Pressure (COP) of the body on a posturography force plate, and the postural sway metrics subsequently calculated. A laboratory experiment was designed to collect postural and task performance data from 18 subjects performing the two batteries of tests in the virtual environment. The results demonstrated a significant decrease in the Root-Mean Square (RMS) of COP along the anterior-posterior axis during the Randomized Pursuit Task (RPT) and maximum body sway of the center of pressure (COP) in the mediolateral direction during both tests. Also, subjects exposed to high elevation predominately exhibit higher accuracy for RPT (P-value = 0.02) and lower accuracy for HST (P-value = 0.05). The results show that the combination of elevation-related visual depth and low-complexity dual tasks impairs task performance due to the elevation-induced visual perturbations and anxiety-driven motor responses. On the other hand, in the absence of visual depth at height, high task complexity surprisingly improves the pursuit tracking performance. As expected, during both tasks, alterations in postural control were manifested in the form of a body sway decrement as a compensatory postural strategy for accomplishing tasks at high elevation.
Keywords
Task Performance; Construction Workers; Test Design; Cognitive Load; Standing Position; Sitting Position; Neurophysiological Test; Postural Stability; Virtual Reality; Workers' Safety At Height; Fall-risk; Reaction-time; Fear; Real; Acrophobia; Balance; Safety
Lee, Yong-Cheol; Shariatfar, Moeid; Rashidi, Abbas; Lee, Hyun Woo. (2020). Evidence-Driven Sound Detection for Prenotification and Identification Of Construction Safety Hazards and Accidents. Automation In Construction, 113.
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Abstract
As the construction industry experiences a high rate of casualties and significant economic loss associated with accidents, safety has always been a primary concern. In response, several studies have attempted to develop new approaches and state-of-the-art technology for conducting autonomous safety surveillance of construction work zones such as vision-based monitoring. The current and proposed methods including human inspection, however, are limited to consistent and real-time monitoring and rapid event recognition of construction safety issues. In addition, the health and safety risks inherent in construction projects make it challenging for construction workers to be aware of possible safety risks and hazards according to daily planned work activities. To address the urgent demand of the industry to improve worker safety, this study involves the development of an audio-based event detection system to provide daily safety issues to laborers and through the rapid identification of construction accidents. As an evidence-driven approach, the proposed framework incorporates the occupational injury and illness manual data, consisting of historical construction accident data classified by types of sources and events, into an audio-based safety event detection framework. This evidence-driven framework integrated with a daily project schedule can automatically provide construction workers with prenotifications regarding safety hazards at a pertinent work zone as well as consistently contribute to enhanced construction safety monitoring by audio-based event detection. By using a machine learning algorithm, the framework can clearly categorize the narrowed-down sound training data according to a daily project schedule and dynamically restrict sound classification types in advance. The proposed framework is expected to contribute to an emerging knowledge base for integrating an automated safety surveillance system into occupational accident data, significantly improving the accuracy of audio-based event detection.
Keywords
Construction Projects; Occupational Hazards; Construction Workers; Construction; System Safety; Video Surveillance; Work-related Injuries; Audio-based Accident Recognition; Autonomous Safety Surveillance; Construction Safety; Evidence-driven Sound Event Detection; Accident Prevention; Accidents; Audio Acoustics; Classification (of Information); Construction Industry; Health Hazards; Health Risks; Knowledge Based Systems; Learning Algorithms; Losses; Machine Learning; Monitoring; Motion Compensation; Occupational Diseases; Steel Beams And Girders; Audio-based; Construction Accidents; Construction Work Zones; Historical Construction; Sound Event Detection; State-of-the-art Technology; Vision Based Monitoring; Algorithm; System
Shang, Luming; Migliaccio, Giovanni C. (2020). Demystifying Progressive Design Build: Implementation Issues and Lessons Learned through Case Study Analysis. Organization Technology And Management In Construction, 12(1), 2095 – 2108.
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Abstract
The design-build (DB) project delivery method has been used for several decades in the US construction market. DB contracts are usually awarded on the basis of a multicriteria evaluation, with price as one of the most salient criteria. To ensure the project's success, an owner usually has to invest enough time and effort during scoping and early design to define a program, scope, and budget, ready for procurement and price generation. However, this process can become a burden for the owner and may lengthen the project development duration. As an alternative to the traditional DB, the progressive design-build (PDB) approach permits the selection of the DB team prior to defining the project program and/or budget. PDB has the advantage of maintaining a single point of accountability and allowing team selection based mainly on qualifications, with a limited consideration of price. Under PDB, the selected team works with the project stakeholders during the early design stage, while helping the owner balance scope and budget. However, the key to the effectiveness of PDB is its provision for the ongoing and complete involvement of the owner in the early design phase. Due to the differences between PDB and the other project delivery methods (e.g., traditional DB), project teams must carefully consider several factors to ensure its successful implementation. The research team conducted a case study of the University of Washington's pilot PDB project to complete the West Campus Utility Plant (WCUP). This paper carefully explores and summarizes the project's entire delivery process (e.g., planning, solicitation, design, and construction), its organizational structures, and the project performance outcomes. The lessons learned from the WCUP project will contribute to best practices for future PDB implementation.
Keywords
Progressive Design Build; Project Delivery Method
Choi, Kunhee; Bae, Junseo; Yin, Yangtian; Lee, Hyun Woo. (2021). Act(2): Time Cost Tradeoffs from Alternative Contracting Methods. Journal Of Management In Engineering, 37(1).
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Abstract
Incentive/disincentive (I/D) and cost-plus-time (A+B) are two of the most widely used alternative contracting methods (ACMs) for accelerating the construction of highway infrastructure improvement projects. However, little is known about the effects of trade-offs in terms of project schedule and cost performance. This study addresses this problem by creating and testing a stochastic decision support model called accelerated alternative contracting cost-time trade-off (ACT(2)). This model was developed by a second-order polynomial regression analysis and validated by the predicted error sum of square statistic and paired comparison tests. The results of a descriptive trend analysis based on a rich set of high-confidence project data show that I/D is effective at reducing project duration but results in higher cost compared to pure A+B and conventional methods. This cost-time trade-off effect was confirmed by the ACT(2) model, which determines the level of cost-time trade-off for different ACMs. This study will help state transportation agencies promote more effective application of ACMs by providing data-driven performance benchmarking results when evaluating competing acceleration strategies and techniques. (C) 2020 American Society of Civil Engineers.
Keywords
Highway; Construction; Model; Alternative Contracting Methods; Cost-plus-time; A Plus B; Incentive; Infrastructure Trend; Time-cost Trade-off
Lin, Lin; Chen, Xueming (Jimmy); Moudon, Anne Vernez. (2021). Measuring the Urban Forms of Shanghai’s City Center and Its New Districts: A Neighborhood-Level Comparative Analysis. Sustainability, 13(15).
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Abstract
Rapid urban expansion has radically transformed the city centers and the new districts of Chinese cities. Both areas have undergone unique redevelopment and development over the past decades, generating unique urban forms worthy of study. To date, few studies have investigated development patterns and land use intensities at the neighborhood level. The present study aims to fill the gap and compare the densities of different types of developments and the spatial compositions of different commercial uses at the neighborhood level. We captured the attributes of their built environment that support instrumental activities of daily living of 710 neighborhoods centered on the public elementary schools of the entire Shanghai municipality using application programming interfaces provided in Baidu Map services. The 200 m neighborhood provided the best fit to capture the variations of the built environment. Overall, city center neighborhoods had significantly higher residential densities and housed more daily routine destinations than their counterparts in the new districts. Unexpectedly, however, the total length of streets was considerably smaller in city-center neighborhoods, likely reflecting the prominence of the wide multilane vehicular roads surrounding large center city redevelopment projects. The findings point to convergence between the city center's urban forms and that of the new districts.
Keywords
Quantifying Spatiotemporal Patterns; Fast-food Restaurants; Instrumental Activities; Physical-activity; Chinese Cities; Land; Schools; Redevelopment; Expansion; Transformation; Built Environment; Planning; Neighborhood; Urban Form; Shanghai