Ottesen, Jeffrey L., & Migliaccio, Giovanni (2023). Use of Predictive Models for Labor-Productivity Loss in Settling Disputes. Journal of Legal Affairs and Dispute Resolution in Engineering and Construction, 15(1).
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Abstract
Given inherent difficulties in construction, optimizing labor efficiencies is paramount to project success. Research described in this article conducted demonstrates that an analysis of planned activities in a critical path methodology (CPM) schedule may be used to forecast future productivity inefficiencies. Specifically, this study relies on the concept of CPM schedule’s density, which is defined as the number of overlapping like-trade activities on any given workday. This metric is directly related to the required labor resources required to complete that work within the activities’ planned durations. Schedule density increases where more planned activities overlap with each other; for instance, occurrence of such increases is common when the schedule is accelerated. Regression models were derived using metrics drawn from CPM schedule updates’ activities and durations and compared to actual labor productivity experienced. Strong correlation findings support development of predictive models that quantify potential labor inefficiencies before they occur. However, the question remains as to the strength and applicability of predictive models in formal litigation. This paper presents findings of this research and discusses how such findings may be used to facilitate settlement in dispute resolution procedures.
Keywords
Migliaccio, Giovanni C., Gebken, Richard J., Fernandez, Luis R., & Osmanbhoy, Natasha (2022). Emergent Subcontracting Models in the US Construction Industry. Journal of Legal Affairs and Dispute Resolution in Engineering and Construction, 14(4).
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Abstract
Prime contracting models for engineering and construction projects are described extensively in the literature, but models between prime contractors and subcontractors are less well known. This study examined the established and evolving subcontracting models in the US construction industry to not only document their utilization but also investigate their advantages and disadvantages when employed. The research followed a two-phase/two-step approach. During Phase 1, the authors completed a regionally based study to identify subcontracting practices in the Pacific Northwest. As part of Phase 2, the study was expanded across the United States to gain a greater understanding of each of the identified subcontracting models, including advantages, disadvantages, and variations. Both phases were organized into two steps: (1) an online survey instrument was sent to professionals with either general or specialty contracting firms, and (2) follow-up semistructured interviews were conducted with selected survey respondents to better evaluate each subcontracting model. The authors found that five subcontracting models address the most common scenarios and the characteristics of each are familiar to the nationwide participant sample. There are subtle variations to the main five models that are being employed to varying degrees across the country. The impetus for these variations appears to be founded on the need to find better contractual arrangements and that subcontracting practices are dynamic by nature. Although most of the participants were from western and central divisions of the US Census Bureau geographical classification, participants from all geographic areas participated in the study. Increasing knowledge on how project delivery systems may affect disputes and claims or conflicts and legal issues of procurement systems, this article uniquely contributes to defining a taxonomy of subcontracting models while giving insights into the current and emerging trends in subcontracting practices, including how subcontractors are integrated into a project team.
Saelens, Brian E., Hurvitz, Philip M., Zhou, C., Colburn, T., Marchese, A., & Moudon, Anne Vernez (2022). Impact of a Light Rail Transit Line on Physical Activity: Findings from the Longitudinal Travel Assessment and Community (TRAC) Study. Journal of Transport & Health, 27.
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Abstract
Increasing transit infrastructure could increase transit use and result in higher physical activity if users actively travel to access transit. Few studies have rigorously examined transit use and physical activity change from before to years after among residents living close versus farther away from new transit options.Methods: An initial sample (n = 722) of residents living either close (1 mile network distance; unexposed) from future new light rail transit (LRT) stops in the Seattle/King County area were recruited and assessed prior to LRT opening and again 1-2 and 3-4 years later. At each assessment timepoint, residents wore an accelerometer and GPS data logger for 7 days and completed a 7-day travel log and demographic and attitudinal survey. Difference-in-difference analyses examined longitudinal change between those exposed versus unexposed to LRT in physical activity, walking (both utilitarian and recreational), and transit-related walking, and transit use.Results: There was no differential change by LRT exposure in overall physical activity (including or not including light intensity physical activity), recreational walking, or utilitarian walking, with most decreasing significantly in both exposure conditions through follow-ups. There was a differential change in transit-related walking, with those exposed to LRT slightly increasing such physical activity to the most distal follow-up, but the difference from the unexposed condition was modest (<2 min/day). There was no substantial differential change over time in transit use by LRT exposure.Conclusions: Exposure to a new light rail line did not markedly change the frequency of transit use of nearby residents, but did result in a small increase in transit-related walking relative to those unexposed. This did not differentially change the amount of overall physical activity or time spent walking compared to residents living farther away from the new LRT.
Keywords
Public Transit; Accelerometer Data; Built Environment; Behavior; Walking; Transportation; Neighborhood; Time; GPS
Lee, Sungmin, Lee, Chanam, Won Nam, Ji, Vernez Moudon, Anne, & Mendoza, Jason A. (2023). Street Environments and Crime around Low-income and Minority Schools: Adopting an Environmental Audit Tool to Assess Crime Prevention Through Environmental Design (CPTED). Landscape and Urban Planning, 232.
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Abstract
• CPTED principles have been applied in school neighborhood safety. • Multiple crime types had significant associations with CPTED principles. • The cleanliness of streets and visual quality of buildings can reduce crime. • Being adjacent to multi-family housing and bus stops can increase crime. • The findings add to the evidence supporting the effectiveness of CPTED initiatives. Crime prevention through environmental design (CPTED) suggests an association between micro-scale environmental conditions and crime, but little empirical research exists on the detailed street-level environmental features associated with crime near low-income and minority schools. This study focuses on the neighborhoods around 14 elementary schools serving lower income populations in Seattle, WA to assess if the distribution of crime incidences (2013–2017) is linked with the street-level environmental features that reflect CPTED principles. We used a total of 40 audit variables that were included in the four domains derived from the broken windows theory and CPTED principles: natural surveillance (e.g., number of windows, balconies, and a sense of surveillance), territoriality (e.g., crime watch signs, trees), image/maintenance (e.g., graffiti and a sense of maintenance/cleanness), and geographical juxtaposition (e.g., bus stops, presence of arterial). We found that multiple crime types had significant associations with CPTED components at the street level. Among the CPTED domains, two image/maintenance features (i.e., maintenance of streets and visual quality of buildings) and two geographical juxtaposition features (i.e., being adjacent to multi-family housing and bus stops) were consistently associated with both violent and property crime. The findings suggest that local efforts to improve maintenance of streets and visual quality of buildings and broader planning efforts to control specific land uses near schools are important to improve safety in marginalized neighborhoods near schools that tend to be more vulnerable to crime. Our research on micro-scale environmental determinants of crime can also serve as promising targets for CPTED research and initiatives. [ABSTRACT FROM AUTHOR]
Keywords
CPTED; Crime; Environmental audit; Micro-scale environment of Crime; Street environments
Lindell, Michael K; Jung, Meen Chel; Prater, Carla S; House, Donald H (2023). Evaluation of Hazard Brochures Using Topic Viewing Durations: Application to Tsunami Evacuation Brochures. Risk Analysis.
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Abstract
This study describes a novel method of assessing risk communication effectiveness by reporting an evaluation of a tsunami information brochure by 90 residents of three Pacific coast communities that are vulnerable to a Cascadia Subduction Zone earthquake and tsunami—Commencement Bay, Washington; Lincoln City, Oregon; and Eureka, California. Study participants viewed information that was presented in DynaSearch, an internet‐based computer system that allowed them to view text boxes and tsunami inundation zone maps. DynaSearch recorded the number of times each text box or map was clicked and the length of time that it was viewed. This information viewing phase was followed by questionnaire pages assessing important aspects of tsunami hazard and sources of tsunami warnings. Participants gave the longest click durations to what to do in the emergency period during earthquake shaking and in its immediate aftermath before a tsunami arrives—topics that should be displayed prominently in tsunami brochures and emphasized in talks to community groups. The smallest adjusted click durations were associated with advance preparations for a tsunami—topics that can be posted on websites whose URLs are printed in the brochures.
Keywords
DynaSearch; hazard awareness brochure; Protective Action Decision Model
Rottle, Nancy, Bowles, Mason, Andrews, Leann, & Engelke, Jennifer (2023). Constructed Floating Wetlands: A “Safe‐to‐Fail” Study with Multi‐sector Participation. Restoration Ecology, 31(1).
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Abstract
The Duwamish River Floating Wetlands project designed, built, and deployed constructed floating wetlands in the estuary of the urban Duwamish River in Seattle, Washington, during the 2019 and 2020 outmigration seasons for juvenile salmon. Using a “safe‐to‐fail” methodology and adaptive management strategies, these innovative floating wetland prototypes were custom designed to provide the native plants, invertebrates and slow water habitat that juvenile salmon require during their transition from fresh to salt water, and were monitored for these outcomes. This paper will provide insight into the prototype designs, adaptive management strategies and plant performance, and unique public‐private‐academic‐community partnerships that supported 2 years of design and research.
Keywords
community science; cross‐sector collaboration; designed ecosystems; Duwamish River; ecological restoration; green infrastructure
Ashour, Lamis Abu; Shen, Qing. (2022). Incorporating Ride-sourcing Services into Paratransit for People with Disabilities: Opportunities and Barriers. Transport Policy, 126, 355–363.
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Abstract
The Americans with Disabilities Act (ADA) requires public transit agencies to provide an equivalent transportation service for people with disabilities, known as ADA paratransit service. As the U.S. population continues to grow and age, the demand for paratransit service keeps rising, posing many challenges for transit agencies due to its high operational cost. In response, a growing number of transit agencies are looking to incorporate alternative paratransit services by forming partnerships with transportation network companies (TNCs) to provide what is known as same-day service (SDS). However, most of these partnerships are still in the pilot phase, and scant research investigates the opportunities and barriers of SDS or provides guidelines and measures for transit agencies interested in such partnerships. Considering both the characteristics of paratransit trips and riders and the operational norms of TNCs, this paper explores different conditions under which SDS trips are most appropriate and estimates potential trip diversion from conventional paratransit to SDS operated by TNCs. Trip diversion conditions include (1) trip length, which is impacted by the subsidy amount for SDS and the dynamic pricing of TNC trips, (2) level of service, which depends on the level of mobility assistance required by paratransit riders, and (3) the operational efficiency of conventional paratransit. Different settings and combinations of these conditions help transit agencies explore the potential trip diversion of SDS while considering significant barriers to the service. Using 2019 ridership data of Access paratransit, the ADA paratransit services in the Seattle region, this research finds that without an excessive subsidy amount, transit agencies can divert up to 18% of paratransit trips to SDS. This percentage can drop to as low as 11% of paratransit trips if transit agencies further limit the SDS service area to ensure the efficiency of conventional ADA paratransit. This paper concludes that although SDS provides many benefits, significant barriers inherent to TNC business models and paratransit users should be carefully examined when pursuing ADA paratransit-TNC partnerships.
Keywords
ADA Paratransit; Transportation network company (TNC); Ride-sourcing; Transportation equity; Public-private partnership
Wang, Yiyuan; Shen, Qing. (2022). A Latent Class Analysis to Understand Riders’ Adoption of On-demand Mobility Services as a Complement to Transit. Transportation.
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Abstract
On-demand app-based shared mobility services have created new opportunities for complementing traditional fixed-route transit through transit agencies’ efforts to incorporate them into their service provision. This paper presents one of the first studies that rigorously examine riders’ responses to a pilot aimed at providing such a transit-supplementing service. The study conducts latent class analysis on riders of the Via to Transit program, a mobility pilot in the Seattle region where on-demand service was offered to connect transit riders to light rail stations. The analysis identifies three distinct rider groups with heterogenous responses to the on-demand service: (1) riders who previously used private cars or ride-hailing; (2) riders who were pedestrians and bikers but switched likely because of safety concern; (3) mostly socio-economically disadvantaged riders who previously relied on the bus, but switched to the new service for the convenience and speed. These results point to rich transportation policy implications, which can inform decision-making by public transit agencies as they are exploring alternative ways to deliver the mobility services.
Keywords
Public transit; On-demand shared mobility; Latent class analysis; Heterogeneous travel behavior responses; Built environments
Shi, Xiao; Richards, Mary; Moudon, Anne Vernez; Lee, Brian H. Y.; Shen, Qing; & Ban, Xuegang. (2022). Changes in Perceived Work-from-Home Productivity during the Pandemic: Findings from Two Waves of a Covid-19 Mobility Survey. Findings.
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Abstract
A two-wave survey of workers in Seattle revealed an increase in self-reported work productivity over time for those who shifted to work from home (WFH) since the outbreak of Covid-19. Teleworkers with higher household income adapted better and were more likely to report an increase in productivity as they continued WFH. While those living with friends and relatives were more likely to report a decrease in productivity as they telework for longer. Commute trip reduction programs might encourage the portion of the population with such characteristics to continue WFH after the pandemic subsides and provide support to those with fewer recourses to telework productively if they choose to.
Keywords
work from home; teleworking; work productivity; commute trip reduction; transportation demand management; natural experiment; covid-19
Shi, Xiao; Moudon, Anne Vernez; Lee, Brian H. Y.; Shen, Qing; Ban, Xuegang (Jeff). (2020). Factors Influencing Teleworking Productivity – a Natural Experiment during the COVID-19 Pandemic. Findings.
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Abstract
Of 2174 surveyed adults who were teleworking following the implementation of a Covid-19 work-from-home policy, 23.8% reported an increase in productivity, 37.6% no change, and 38.6% a decrease in productivity compared to working at their prior workplace. After controlling for feelings of depression and anxiety likely caused by pandemic-related circumstances, the socioeconomic characteristics associated with no change or an increase in productivity after shifting to teleworking included being older; not employed in higher education; having lower education attainment; and not living with children. Respondents with longer commute trips in single-occupancy vehicles prior to teleworking were more likely to be more productive but those with longer commute by walking were not. Lifestyle changes associated with increased productivity included better sleep quality, spending less time on social media, but more time on personal hobbies.