This page has only limited features, please log in for full access.

Prof. Samuel Labi
Lyles School of Civil Engineering, Purdue University, West Lafayette, IN 47906, USA

Basic Info

Basic Info is private.

Research Keywords & Expertise

0 smart mobility
0 Sustainable Transportation Systems
0 Autonomous transportation
0 Electric transportation
0 Traffic congestion management

Fingerprints

Electric transportation

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Editorial
Published: 31 July 2021 in Computer-Aided Civil and Infrastructure Engineering
Reads 0
Downloads 0
ACS Style

Samuel Labi. An influential journal elevating the civil engineering profession and raising its image in the engineering league. Computer-Aided Civil and Infrastructure Engineering 2021, 1 .

AMA Style

Samuel Labi. An influential journal elevating the civil engineering profession and raising its image in the engineering league. Computer-Aided Civil and Infrastructure Engineering. 2021; ():1.

Chicago/Turabian Style

Samuel Labi. 2021. "An influential journal elevating the civil engineering profession and raising its image in the engineering league." Computer-Aided Civil and Infrastructure Engineering , no. : 1.

Review
Published: 02 June 2021 in Journal of Cleaner Production
Reads 0
Downloads 0

This paper reviews the concepts of sustainability as it relates to investment evaluation and decision making in runway pavement reconstruction, widening, or repair. The discussion starts with an overview of sustainability principles applied to these runway improvements, and identifies the decision-making contexts associated with these improvements. A comprehensive and explicit definition of performance goals and the associated decision criteria is prerequisite to runway investment evaluation. Therefore, the paper proposes guidelines to assist airport agencies select appropriate decision criteria for their runway pavement investment evaluations. These guidelines address the tie between the decision criteria and sustainable development principles, as well as the desired attributes not only of individual criteria but also of any set of criteria assembled for runway investment appraisal. The authors then present three case studies of runway development to illustrate instances where airport agencies had explicitly implemented sustainability-related decision criteria. It is anticipated that inferences from these specific applications can help airport agencies assess the full consequences of their runway investment alternatives in terms of costs and benefits to the airport agency, the users (airline companies and passengers), and the community.

ACS Style

B.N.T. Alabi; T.U. Saeed; A. Amekudzi-Kennedy; J. Keller; S. Labi. Evaluation criteria to support cleaner construction and repair of airport runways: A review of the state of practice and recommendations for future practice. Journal of Cleaner Production 2021, 312, 127776 .

AMA Style

B.N.T. Alabi, T.U. Saeed, A. Amekudzi-Kennedy, J. Keller, S. Labi. Evaluation criteria to support cleaner construction and repair of airport runways: A review of the state of practice and recommendations for future practice. Journal of Cleaner Production. 2021; 312 ():127776.

Chicago/Turabian Style

B.N.T. Alabi; T.U. Saeed; A. Amekudzi-Kennedy; J. Keller; S. Labi. 2021. "Evaluation criteria to support cleaner construction and repair of airport runways: A review of the state of practice and recommendations for future practice." Journal of Cleaner Production 312, no. : 127776.

Journal article
Published: 10 April 2021 in Transportation Research Part A: Policy and Practice
Reads 0
Downloads 0

Transportation agencies routinely make repair decisions in numerous contexts which include the timing of different repair treatments over an extended period. The timing policy may be characterized either by a standalone manner that maximizes the outcome or utility of individual treatments at a given time, or by a holistic manner that maximizes the utility of all treatments together within a given horizon period. This study begins with a hypothesis that the effect of the sum of treatment prescriptions may be different from the sum of the effect of individual treatment prescriptions. The paper discusses separate practical applications where each of these two situations is pertinent. The study is based on the use of surface roughness as the indicator of pavement performance, and therefore, the framework includes the development of treatment-specific treatment performance jump and performance loss models in terms of roughness. The framework also includes identification of the optimal roughness thresholds for each pavement treatment as a standalone activity, followed by a determination of the thresholds for each treatment from a holistic standpoint. The latter involves the establishment of an optimal repair schedule over the pavement life cycle and recording the resulting roughness thresholds at which each treatment is recommended for application within the optimal schedule. Then the paper presents a case study to demonstrate application of the framework, and to compare the optimal-schedule thresholds versus the stand-alone thresholds. The case study involved fourteen treatment types, two surface material types (rigid and flexible) and three road functional classes. The results suggest that in this context of highway management, the optimal triggers associated with individual standalone repair treatments are not necessarily the same (and yield inferior outcomes) compared to the application thresholds of those treatments when they are considered within an optimized life-cycle schedule. The results can provide guidance to agencies as they examine or update their current roughness thresholds for each standard treatment and their long-term condition-based or time-based repair schedules. The paper’s framework and results can also help agencies assess the consequences of deviations from a repair timing policy (delayed or hastened applications) due to lack of funds and other causes.

ACS Style

Julie Yu Qiao; Runjia Du; Samuel Labi; Jon D. Fricker; Kumares C. Sinha. Policy implications of standalone timing versus holistic timing of infrastructure interventions: Findings based on pavement surface roughness. Transportation Research Part A: Policy and Practice 2021, 148, 79 -99.

AMA Style

Julie Yu Qiao, Runjia Du, Samuel Labi, Jon D. Fricker, Kumares C. Sinha. Policy implications of standalone timing versus holistic timing of infrastructure interventions: Findings based on pavement surface roughness. Transportation Research Part A: Policy and Practice. 2021; 148 ():79-99.

Chicago/Turabian Style

Julie Yu Qiao; Runjia Du; Samuel Labi; Jon D. Fricker; Kumares C. Sinha. 2021. "Policy implications of standalone timing versus holistic timing of infrastructure interventions: Findings based on pavement surface roughness." Transportation Research Part A: Policy and Practice 148, no. : 79-99.

Journal article
Published: 24 March 2021 in Accident Analysis & Prevention
Reads 0
Downloads 0

In previous research, the effects of commercial vehicle proportions (CVP) on overall crash propensity have been found to be significant, but the results have been varied in terms of the effect direction. In addition, the mediating or moderating effects of roadway attributes on the CVP-vs-safety relationships, have not been investigated. In addressing this gap in the literature, this study integrates databases on crashes, traffic, and inventory for Hong Kong road segments spanning 2014–2017. The classes of commercial vehicles considered are public buses, taxi, and light-, medium- and heavy-goods vehicles. Random-parameter Tobit models were estimated using the crash rates. The results suggest that the CVP of each class show credible effects on the crash rates, for the various crash severity levels. The results also suggest that the interaction between CVP and roadway attributes is credible enough to mediate the effect of CVP on crash rates, and the magnitude and direction of such mediation varies across the vehicle classes, crash severity levels, and roadway attribute type in four ways. First, the increasing effect of taxi proportion on slight-injury crash rate is magnified at road segments with high intersection density. Second, the increasing effect of light-goods vehicle proportion on slight-injury crash rate is magnified at road segments with on-street parking. Third, the association between the medium- and heavy-goods vehicle proportion and killed/severe injury (KSI) crash rate, is moderated by the roadway width (number of traffic lanes). Finally, a higher proportion of medium- and heavy-goods vehicles generally contributes to increased KSI crash rate at road segments with high intersection density. Overall, the findings of this research are expected not only to help guide commercial vehicle enforcement strategy, licensing policy, and lane control measures, but also to review existing urban roadway designs to enhance safety.

ACS Style

Tiantian Chen; N.N. Sze; Sikai Chen; Samuel Labi; Qiang Zeng. Analysing the main and interaction effects of commercial vehicle mix and roadway attributes on crash rates using a Bayesian random-parameter Tobit model. Accident Analysis & Prevention 2021, 154, 106089 .

AMA Style

Tiantian Chen, N.N. Sze, Sikai Chen, Samuel Labi, Qiang Zeng. Analysing the main and interaction effects of commercial vehicle mix and roadway attributes on crash rates using a Bayesian random-parameter Tobit model. Accident Analysis & Prevention. 2021; 154 ():106089.

Chicago/Turabian Style

Tiantian Chen; N.N. Sze; Sikai Chen; Samuel Labi; Qiang Zeng. 2021. "Analysing the main and interaction effects of commercial vehicle mix and roadway attributes on crash rates using a Bayesian random-parameter Tobit model." Accident Analysis & Prevention 154, no. : 106089.

Editorial article
Published: 23 March 2021 in Frontiers in Built Environment
Reads 0
Downloads 0

Editorial on the Research Topic Advances in Planning for Emerging Transportation Technologies: Towards Automation, Connectivity, and Electric Propulsion Transportation systems continue to face significant challenges and opportunities in the context of their social, technical, and economic outcomes (De Neufville and Scholtes, 2011; Kaewunren et al.; Sinha et al., 2017; De Martinis and Corman, 2018; Bongiovanni et al., 2019; Eker et al., 2019; Eker et al., 2020a; Barmpounakis and Geroliminis, 2020; Becker et al., 2020; Eker et al., 2020b; Ahmed et al., 2021). A case in point is the set of ongoing advancements in information and computer technology that offer unprecedented opportunities for realizing or enhancing systems autonomy/automation, and connectivity. These developments continue to lay the building blocks for a new and exciting generation of transportation vehicles and associated infrastructure. This new transformative generation is expected to be characterized by vehicle connectivity and autonomy, emergent transport modes, new operational policies and standards, and enhanced economic productivity. From a social outcomes’ perspective, the need for emissions reduction is motivating the promotion of electric propulsion of vehicles, a feature that is particularly indispensable for efficient operations of connected and autonomous vehicles (CAVs). This special issue crystallizes current thinking and future directions regarding some aspects of the science, engineering, and economic issues associated with the development of CAVs and related technologies. The articles in this special issue addressed the outcomes of next-generation transportation from perspectives that include safety, social and equity concerns (Ahmed et al.; Seilabi et al.) technical concerns in terms of mobility and reliability (Rahman et al.; Büchel and Corman; Ha et al.), economic considerations (Seilabi et al.), and outcomes associated with overall sustainability (Ahmed et al.; Seilabi et al.). Some of the articles in this special issue addressed the issue of transportation demand. For example, Seilabi et al. modeled traveler choices at different levels of market penetration of new technologies as a basis for measuring travel flows and establishing optimal levels of travel credit pricing, and Ahmed et al. explored public perceptions and potential benefits and concerns of a new transport mode, the flying car. In addition, some of the articles recognized that the next-generation technologies will exist not on their own but as part of an amalgamation of concepts so that synergistic benefits can be realized. For example, Ha et al. explained the possible holistic benefits of systems automation and systems connectivity towards transportation system efficiency and safety. The articles in the special issue showed consistency with the concept of smart cities, a concept that is intertwined with new transportation technologies (Shaheen et al., 2019). This includes the automation and connectedness of smart city entities such as its vehicles (Ha et al.) citizenry, infrastructure and services. Seilabi et al. explained how travelers can use vehicle automation/connectivity features to honor travel credits at specific locations or times-of-day consistent with their lane type and link choices. Ahmed et al. examined the viability of advanced air vehicles to overcome persistent urban problems of traffic congestion and road disrepair. The articles in the special issue also provided some guidance on future directions for investments and policy to promote the next generation of transportation systems. Ha et al. discussed how the current and future synergies between systems connectivity and autonomy could help generate knowledge that could be used to justify investments related to these technologies. Ahmed et al. offered insights that can inform next-generation policies and standards associated with the gradual advancement of advanced air vehicles and urban air mobility. Seilabi et al. demonstrated how the transportation agency can keep traditional vehicle travel costs to equitable levels, particularly during early periods of the transition towards the next-generation vehicles. Further, enhanced reliability in travel-time assessment due to enhanced modeling techniques (Büchel and Corman) or due to the use of social media data (Rahman et al.) can help transportation agencies and operators in their tasks of reporting, controlling operations, and disseminating information to not only shippers and travelers, but also to infrastructure planning and policy evaluation units in an agency. The articles in this special issue were motivated by advances in information and computer technology that in turn are fostering the development of automated and/or connected transportation systems or acquisition of information that will help realize this emerging generation transportation systems. The articles in the special issue addressed at least one of the following research activity areas associated with this emerging generation: travel demand assessments; policy and planning including assessments of impacts and their variability; road infrastructure management and network modeling to facilitate CAV adoption; alternative modes; and sharing of real-time information via connectivity of personal communication devices. The topic editors are grateful to the Specialty Chief Editor, Section Editors, and the Review Editors. All authors listed made a substantial, direct and intellectual contribution to the work, and approved it for publication. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Ahmed, S. S., Fountas, G., Eker, U., Still, S. E., and Anastasopoulos, P. C. (2021). An exploratory empirical analysis of willingness to hire and pay for flying taxis and shared flying car services. J. Air Transp. Manag. 90, 101963....

ACS Style

Samuel Labi; Panagiotis Anastasopoulos; Mohammad Miralinaghi; Ghim Ping Ong; Feng Zhu. Editorial: Advances in Planning for Emerging Transportation Technologies: Towards Automation, Connectivity, and Electric Propulsion. Frontiers in Built Environment 2021, 7, 1 .

AMA Style

Samuel Labi, Panagiotis Anastasopoulos, Mohammad Miralinaghi, Ghim Ping Ong, Feng Zhu. Editorial: Advances in Planning for Emerging Transportation Technologies: Towards Automation, Connectivity, and Electric Propulsion. Frontiers in Built Environment. 2021; 7 ():1.

Chicago/Turabian Style

Samuel Labi; Panagiotis Anastasopoulos; Mohammad Miralinaghi; Ghim Ping Ong; Feng Zhu. 2021. "Editorial: Advances in Planning for Emerging Transportation Technologies: Towards Automation, Connectivity, and Electric Propulsion." Frontiers in Built Environment 7, no. : 1.

Journal article
Published: 04 February 2021 in Transportation Research Part A: Policy and Practice
Reads 0
Downloads 0

Highway transportation project bundling can significantly reduce project delivery cost but could cause undesirable consequences such as reduced market competition. As such, bundling policy needs to be guided by a careful assessment of the potential impacts of bundling on bidding competition. This paper analyses the effect of project bundling policies on market competition using random-effects mixed ordinal logistic modelling, a probabilistic approach. The paper also investigates the variations of such effects across the different project types. The bundling policy factors that were found to be significantly impact bidding competition were the bundle size, bundling combination, and spatial proximity. The results suggest that bundled projects are generally associated with lower bidding competition compared to standalone projects, for all work categories except traffic projects. Further, where the bundled projects have proximal location, the bidding competition is generally higher. It was also determined that the different highway project types exhibit significant differences regarding the effect of bundling on competition: bundling policy (vis-à-vis standalone policy) generally leads to less intense competition for bridge, road, small-structures, miscellaneous, and utility projects, and more intense competition for traffic projects. In addition, it was found that there is a significant improvement on the model performance by including a random effects specification which diagnosed and addressed the unobserved heterogeneity that exists across the contract-letting years, for all the project types. The paper’s models can help highway agencies not only estimate the expected number of bidders for a given project under different bundling policies but also assess the effects of the bundling policy-related factors on bidding competition.

ACS Style

Yu Qiao; Samuel Labi; Jon D. Fricker. Does highway project bundling policy affect bidding competition? Insights from a mixed ordinal logistic model. Transportation Research Part A: Policy and Practice 2021, 145, 228 -242.

AMA Style

Yu Qiao, Samuel Labi, Jon D. Fricker. Does highway project bundling policy affect bidding competition? Insights from a mixed ordinal logistic model. Transportation Research Part A: Policy and Practice. 2021; 145 ():228-242.

Chicago/Turabian Style

Yu Qiao; Samuel Labi; Jon D. Fricker. 2021. "Does highway project bundling policy affect bidding competition? Insights from a mixed ordinal logistic model." Transportation Research Part A: Policy and Practice 145, no. : 228-242.

Original article
Published: 23 November 2020 in Computer-Aided Civil and Infrastructure Engineering
Reads 0
Downloads 0

Trade‐off analysis, one of the key tenets of multi‐objective optimization for the project selection problem in Transportation Asset Management (TAM), can help decision‐makers quantify and comprehend the consequences of different resource allocations in terms of the multiple measures of system performance. In analyzing TAM trade‐offs, it is vital to account duly for the uncertainties associated with these system‐wide performance measures. In this paper, we present a methodology that integrates chance‐constraint programming, the Lindeberg Central Limit Theorem, and a hybrid NSGA II method, to address the performance uncertainties associated with the TAM multi‐objective optimization problem. Through analyzing the trade‐offs between expenditure and performance, and between different performance measures, we generate Pareto frontiers at different confidence levels using a hybrid NSGA II method. We demonstrate the proposed methodology using a case study involving real‐life assets and the expected cost and performance benefits of projects associated with these assets. Regarding the trade‐off between cost and performance, we determine the extent to which the strengths of these relationships vary across different confidence levels. We find that, generally, for a given network performance level, a higher expenditure is needed to achieve a high confidence level compared to the expenditure needed to achieve a low confidence level, and more importantly, measures these sensitivities. This is the “Price of Confidence” concept. Regarding the trade‐off between different pairs of performance measures under budgetary constraints, we show how these relationships vary with the confidence level specified for the analysis, and we measure the extent to which higher confidence level requirements translate into lower levels of overall system‐wide performance.

ACS Style

Qiang Bai; Mohammad Miralinaghi; Samuel Labi; Kumares C. Sinha. Methodology for analyzing the trade‐offs associated with multi‐objective optimization in transportation asset management under uncertainty. Computer-Aided Civil and Infrastructure Engineering 2020, 36, 381 -401.

AMA Style

Qiang Bai, Mohammad Miralinaghi, Samuel Labi, Kumares C. Sinha. Methodology for analyzing the trade‐offs associated with multi‐objective optimization in transportation asset management under uncertainty. Computer-Aided Civil and Infrastructure Engineering. 2020; 36 (4):381-401.

Chicago/Turabian Style

Qiang Bai; Mohammad Miralinaghi; Samuel Labi; Kumares C. Sinha. 2020. "Methodology for analyzing the trade‐offs associated with multi‐objective optimization in transportation asset management under uncertainty." Computer-Aided Civil and Infrastructure Engineering 36, no. 4: 381-401.

Journal article
Published: 06 November 2020 in Journal of Safety Research
Reads 0
Downloads 0

Introduction: Walkability continues to attract great attention from urban planners, designers, and engineers as they recognize not only the merits of pedestrian facilities in terms of the health benefits but also their demerits in terms of accident risk to pedestrians. Wide footpaths improve the pedestrian environment and experience, and thereby motivate travelers to walk as much as possible. However, if footpaths are too wide, they may leave a smaller space for the roadway. On the other hand, wide road lanes may lead to higher road vehicle safety but are costly to construct and maintain and also may leave little space for the footpath. Evidently, for a fixed urban space, what is needed is an optimal balance between the vehicle lane and pedestrian path. This problem is encountered routinely in dense cities including Hong Kong where land availability is severely limited. Method: To address the issue, this paper first establishes safety performance functions (SPFs) for the pedestrian space and the road space, using the random-parameter negative binomial regression. The results indicate the extent to which road lane and footpath width changes are associated with changes in in-vehicle occupant and pedestrian casualties. Then the paper uses the SPFs to develop a methodology for optimizing the width allocations to the road lanes and footpaths, duly considering the user (safety) costs and agency (construction) costs associated with each candidate allocation of the widths. Finally, the paper analyzes the sensitivity of the optimal solution to the relative weights of user cost and agency cost. Results: When user and agency costs are considered equally important, the optimal lane width is 5.4 m. Conclusion: It is observed that the road space allocation ratio used by the Hong Kong road agency suggests that the agency places a higher weight to user cost compared to agency cost. Practical Application: The findings can help incorporate design-safety relationships, and the stakeholders (agency and users) perspectives in urban road and footpath design.

ACS Style

Tiantian Chen; N.N. Sze; Sikai Chen; Samuel Labi. Urban road space allocation incorporating the safety and construction cost impacts of lane and footpath widths. Journal of Safety Research 2020, 75, 222 -232.

AMA Style

Tiantian Chen, N.N. Sze, Sikai Chen, Samuel Labi. Urban road space allocation incorporating the safety and construction cost impacts of lane and footpath widths. Journal of Safety Research. 2020; 75 ():222-232.

Chicago/Turabian Style

Tiantian Chen; N.N. Sze; Sikai Chen; Samuel Labi. 2020. "Urban road space allocation incorporating the safety and construction cost impacts of lane and footpath widths." Journal of Safety Research 75, no. : 222-232.

Preprint
Published: 19 April 2020
Reads 0
Downloads 0

This paper aims to provoke fundamental thinking and action around the value and importance of socially-equitable development to the economic advancement, resilience, and prosperity of communities, as we contend with the 21st Century grand challenge of the changing climate and disasters. As local communities and the global community have experienced an increased frequency, intensity and duration of natural and man-made disasters over the past several decades, opportunities have also grown to identify and reap the benefits of socially-equitable economic development. Reflecting on the COVID-19 pandemic, we discuss the critical importance of socially-equitable economic development to the resilience and sustainability of communities and the infrastructure that supports them. To this end, we: (1) examine what constitutes socially-equitable economic development at different spatial scales of community; (2) explore whether socially-equitable development can occur at different scales of community; (3) explicate the importance of formally considering the inputs, processes, outputs and outcomes for socially-equitable development; (4) explain why the pursuit of equal distribution of the benefits and burdens of development is a necessary but not sufficient endeavor for socially-equitable economic development; (5) analyze the relationships between socially-equitable development, and resilient and sustainable infrastructure and communities; (6) explain why socially-equitable development should be a key component of infrastructure and community resilience strategies in the 21st Century; and, (7) explain why socially-equitable development can ultimately be viewed as a long-term strategy for prosperity.

ACS Style

Adjo Amekudzi-Kennedy; Samuel Labi; Brian Woodall; Greg Marsden; Emily Grubert. Role of Socially-Equitable Economic Development in Creating Resilient and Sustainable Systems: COVID-19-Related Reflections. 2020, 1 .

AMA Style

Adjo Amekudzi-Kennedy, Samuel Labi, Brian Woodall, Greg Marsden, Emily Grubert. Role of Socially-Equitable Economic Development in Creating Resilient and Sustainable Systems: COVID-19-Related Reflections. . 2020; ():1.

Chicago/Turabian Style

Adjo Amekudzi-Kennedy; Samuel Labi; Brian Woodall; Greg Marsden; Emily Grubert. 2020. "Role of Socially-Equitable Economic Development in Creating Resilient and Sustainable Systems: COVID-19-Related Reflections." , no. : 1.

Preprint
Published: 06 April 2020
Reads 0
Downloads 0

Humanity’s social and economic development has been challenged by a range of adversities over the millennia that have caused widespread and unimaginable suffering. At the same time, these challenges have forced humans to evolve more wisely, overcoming adversity through creativity and leading to advancements in science and technology, medicine, ethics and legal systems, and socio-political systems. The dynamics of risks and opportunities caused by COVID-19, in the built, cyber, social and economic environments, present opportunities for deepening our understanding of resilient and sustainable development and infrastructure. This article reflects on five lessons that COVID-19 is teaching us about what it means to develop sustainably through the lens of transportation: (1) sustainable development planning and analytical frameworks must be comprehensive, for long-term sustainability; (2) multi-modal transportation is a superior vision for sustainable development than any one particular mode; (3) tele-activities are part of an effective infrastructure sustainability strategy; (4) economic capital is critically important to sustainable development even when it is not a critical existential threat, and, (5) effective social capital is essential in global disaster resistance and recovery, and can and must be leveraged between fast-moving and slow-moving disasters. Resilient and sustainable infrastructure will continue to be critical to addressing evolving natural and man-made hazards in the 21st Century.

ACS Style

Adjo Amekudzi-Kennedy; Samuel Labi; Brian Woodall; Mikhail Chester; Prerna Singh. Reflections on Pandemics, Civil Infrastructure and Sustainable Development: Five Lessons from COVID-19 through the Lens of Transportation. 2020, 1 .

AMA Style

Adjo Amekudzi-Kennedy, Samuel Labi, Brian Woodall, Mikhail Chester, Prerna Singh. Reflections on Pandemics, Civil Infrastructure and Sustainable Development: Five Lessons from COVID-19 through the Lens of Transportation. . 2020; ():1.

Chicago/Turabian Style

Adjo Amekudzi-Kennedy; Samuel Labi; Brian Woodall; Mikhail Chester; Prerna Singh. 2020. "Reflections on Pandemics, Civil Infrastructure and Sustainable Development: Five Lessons from COVID-19 through the Lens of Transportation." , no. : 1.

Journal article
Published: 04 April 2020 in European Journal of Operational Research
Reads 0
Downloads 0

One of the major causes of non-recurrent traffic congestion in urban areas is the implementation of transport infrastructure projects on city roads. The seeming ubiquity of work zones in cities causes road user frustration and safety hazards, and public relations problems for the transport agency. For this reason, transport agencies seek strategic ways to not only select urban projects but also schedule them in a manner that minimizes the effort associated with these functions. In other words, they seek to exploit the synergies between the tasks of project selection and project scheduling while duly accommodating the project interdependencies. This study introduces a general framework that simultaneously and optimally selects and schedules urban road projects subject to budgetary constraints over a given planning horizon. The project classes considered in this study are lane addition, new road construction, and road maintenance. Through a mimicry of the classic Stackelberg leader-follower game, this problem is formulated herein as a bi-level program. In the upper level, the leader (transport agency decision-makers) determines an optimal set of projects from a larger pool of candidate projects and decides an optimal schedule for their implementation. In the lower level, the followers (road users) seek to minimize their travel delays based on the two decisions made by the leader in the upper level. The numerical experiments show that if the decision-makers do not consider the peri-implementation capacity reduction, the resulting set of selected projects and their construction schedule can lead to significant travel delay cost for the road users.

ACS Style

Mohammad Miralinaghi; Sania E. Seilabi; Sikai Chen; Yu-Ting Hsu; Samuel Labi. Optimizing the selection and scheduling of multi-class projects using a Stackelberg framework. European Journal of Operational Research 2020, 286, 508 -522.

AMA Style

Mohammad Miralinaghi, Sania E. Seilabi, Sikai Chen, Yu-Ting Hsu, Samuel Labi. Optimizing the selection and scheduling of multi-class projects using a Stackelberg framework. European Journal of Operational Research. 2020; 286 (2):508-522.

Chicago/Turabian Style

Mohammad Miralinaghi; Sania E. Seilabi; Sikai Chen; Yu-Ting Hsu; Samuel Labi. 2020. "Optimizing the selection and scheduling of multi-class projects using a Stackelberg framework." European Journal of Operational Research 286, no. 2: 508-522.

Original article
Published: 05 January 2020 in Computer-Aided Civil and Infrastructure Engineering
Reads 0
Downloads 0

Construction projects are often associated with partial or full road closures, which result in user costs and community disruptions in terms of reduced business productivity. A number of studies have addressed the problem of scheduling construction projects based on a variety of stakeholder objectives. Yet still, there seems to exist a few gaps regarding (1) possible tradeoffs between road user cost reduction and business cost reduction associated with optimal scheduling, (2) role of the project type (rehabilitation and capacity expansion) on the solution methodology, and (3) lack of solution algorithm to address the problem complexity by deriving the optimal solution. In addressing these gaps, this article adopts a novel approach for developing an optimal project schedule for multiple road projects within a construction horizon. The goal is to minimize the overall cost of the projects to road users and adjacent businesses over the construction horizon. The project scheduling problem is formulated as a mixed‐integer nonlinear program. We solve the problem using a local decomposition method. The methodology is demonstrated using the Sioux Falls city network with two project types: capacity expansion and rehabilitation. The results of the numerical experiment suggest that (1) the solution algorithm converges to optimal solution in finite iterations and (2) a network‐wide scheduling of urban road projects using explicit optimization can yield a significant reduction in business disruption costs while incurring a relatively smaller increase in system travel time, and overall, is superior to a schedule developed only considering the total system travel time.

ACS Style

Mohammad Miralinaghi; Wubeshet Woldemariam; Dulcy M. Abraham; Sikai Chen; Samuel Labi; Zhibin Chen. Network‐level scheduling of road construction projects considering user and business impacts. Computer-Aided Civil and Infrastructure Engineering 2020, 35, 650 -667.

AMA Style

Mohammad Miralinaghi, Wubeshet Woldemariam, Dulcy M. Abraham, Sikai Chen, Samuel Labi, Zhibin Chen. Network‐level scheduling of road construction projects considering user and business impacts. Computer-Aided Civil and Infrastructure Engineering. 2020; 35 (7):650-667.

Chicago/Turabian Style

Mohammad Miralinaghi; Wubeshet Woldemariam; Dulcy M. Abraham; Sikai Chen; Samuel Labi; Zhibin Chen. 2020. "Network‐level scheduling of road construction projects considering user and business impacts." Computer-Aided Civil and Infrastructure Engineering 35, no. 7: 650-667.

Articles
Published: 28 November 2019 in Structure and Infrastructure Engineering
Reads 0
Downloads 0

In recent years, there has been an increasing trend towards viewing complex infrastructure systems in a holistic manner, to better understand their behaviour. This paper extends the holism concept to facilitate comprehension of the deterioration of the three bridge components: the deck, superstructure, and substructure. The hypothesis is that these bridge components deteriorate, not in isolation, but collectively as a system of systems, and therefore their deterioration exhibits substantial interdependency. To investigate these interdependencies, this paper uses National Bridge Inventory (NBI) data. The paper explores the efficacy of using a multivariate three-stage least squares (3SLS) model to describe these interdependencies and to quantify the effects of other explanatory factors on the deterioration of these components. The results of the 3SLS model are compared to traditional linear models estimated using ordinary least squares (OLS), to demonstrate the 3SLS model’s ability to return more precise estimates of bridge deterioration effects. The results show that the 3SLS model statistically outperforms the OLS models by an average of 104% and 173%, based on root mean square error and mean absolute percentage error, respectively. These results support the hypothesis that bridge components exhibit system-of-systems behavior as their deterioration levels are influenced by the condition of each other. The results also suggest that such holistic nature can be captured using a simultaneous equation model. Improved condition prediction can enhance confidence in agency bridge management functions and result in a more efficient use of limited public resources for infrastructure maintenance and repair.

ACS Style

Steven M. Lavrenz; Tariq Usman Saeed; Jackeline Murillo-Hoyos; Matthew Volovski; Samuel Labi. Can interdependency considerations enhance forecasts of bridge infrastructure condition? Evidence using a multivariate regression approach. Structure and Infrastructure Engineering 2019, 16, 1177 -1185.

AMA Style

Steven M. Lavrenz, Tariq Usman Saeed, Jackeline Murillo-Hoyos, Matthew Volovski, Samuel Labi. Can interdependency considerations enhance forecasts of bridge infrastructure condition? Evidence using a multivariate regression approach. Structure and Infrastructure Engineering. 2019; 16 (8):1177-1185.

Chicago/Turabian Style

Steven M. Lavrenz; Tariq Usman Saeed; Jackeline Murillo-Hoyos; Matthew Volovski; Samuel Labi. 2019. "Can interdependency considerations enhance forecasts of bridge infrastructure condition? Evidence using a multivariate regression approach." Structure and Infrastructure Engineering 16, no. 8: 1177-1185.

Journal article
Published: 23 October 2019 in Transportation Research Part A: Policy and Practice
Reads 0
Downloads 0

As highway agencies seek project delivery strategies that can help minimize their overall costs, interest in the practice of project bundling, which refers to the combining of multiple projects of similar or different work types into a single contract, continues to increase. The past literature contains studies about the effects of bundling, particularly from a conceptual perspective, but with only minimal quantitative analysis of empirical data from past bundling projects. Past researchers hypothesized that the magnitude and direction of the effects of bundling policies on project cost differ not only across different market conditions but also across different highway project types. In seeking to test this hypothesis, this paper presents analysis that utilized past project cost data to verify the effects of these project-related and bundling-related factors on bundling outcomes. In the analysis that quantified the extent to which increasing the bundle size causes a reduction in the bidding competition, it was determined that this outcome varies across the different project types. In addition, using Monte Carlo simulation, the study established the bundle size threshold (the bundle size beyond which the project cost increases) and quantified the uncertainties associated with cost estimates that arise from varying bidding competition conditions; these were also found to vary across the different project types. The models introduced in this paper can be used by highway agencies at the early (planning) stages of development of a given project type, to predict the expected project award cost for different bundling alternatives and under different market uncertainties. Heightened awareness of the cost consequences across the different bundling policies, bidding market conditions, and project types can provide guidance to agencies that seek to establish or update project bundling policies.

ACS Style

Yu Qiao; Jon D. Fricker; Samuel Labi. Effects of bundling policy on project cost under market uncertainty: A comparison across different highway project types. Transportation Research Part A: Policy and Practice 2019, 130, 606 -625.

AMA Style

Yu Qiao, Jon D. Fricker, Samuel Labi. Effects of bundling policy on project cost under market uncertainty: A comparison across different highway project types. Transportation Research Part A: Policy and Practice. 2019; 130 ():606-625.

Chicago/Turabian Style

Yu Qiao; Jon D. Fricker; Samuel Labi. 2019. "Effects of bundling policy on project cost under market uncertainty: A comparison across different highway project types." Transportation Research Part A: Policy and Practice 130, no. : 606-625.

Original article
Published: 01 September 2019 in Computer-Aided Civil and Infrastructure Engineering
Reads 0
Downloads 0

Autonomous vehicle (AV) stakeholders continue to seek assurance of the safety performance of this new technology through AV testing on in‐service roads, AV‐dedicated road networks, and AV test tracks. However, recent AV‐related fatalities on in‐service roads have exacerbated public skepticism and eroded some public trust in the safety of AV operations. Further, test tracks are unable to characterize adequately the real‐world driving environment. For this reason, driving simulators continue to serve as an attractive means of AV testing. However, in most AV driving simulators, the AV operation is based on commands external to the vehicle and embedded in the code for the driving environment. To address the simulation shortfalls associated with this approach, this paper develops a deep convolutional neural network–long short‐term memory (CNN–LSTM) algorithm for self‐driving simulation. This algorithm observes and characterizes the AV's driving environment, and controls the AV movement in the driving simulation. The CNN part extracts features that use transfer learning to introduce human prior knowledge, and the LSTM part uses temporal information to process the extracted features, and incorporates temporal dynamics to predict driving decisions. The AV may also use an external server with a database containing road environment data as an additional source of information. It is acknowledged that different driving simulators differ in their functions and their capabilities to access driving‐environment data. Therefore, to make it sufficiently flexible to facilitate replication by other researchers that use driving simulators, the algorithm has been designed and demonstrated using only image data of the driving environment as input. This is because roadway image data are easily and readily accessible from the screen of any driving simulator. The proposed algorithm was tested using the open racing car simulator test track platform and was found to be able to mimic human driving decisions with a high degree of accuracy.

ACS Style

Sikai Chen; Yue Leng; Samuel Labi. A deep learning algorithm for simulating autonomous driving considering prior knowledge and temporal information. Computer-Aided Civil and Infrastructure Engineering 2019, 35, 305 -321.

AMA Style

Sikai Chen, Yue Leng, Samuel Labi. A deep learning algorithm for simulating autonomous driving considering prior knowledge and temporal information. Computer-Aided Civil and Infrastructure Engineering. 2019; 35 (4):305-321.

Chicago/Turabian Style

Sikai Chen; Yue Leng; Samuel Labi. 2019. "A deep learning algorithm for simulating autonomous driving considering prior knowledge and temporal information." Computer-Aided Civil and Infrastructure Engineering 35, no. 4: 305-321.

Comparative study
Published: 18 November 2018 in Accident Analysis & Prevention
Reads 0
Downloads 0

This paper examined the accident risk factors associated with highway traffic and roadway design, for each of three highway classes in the United States using a bivariate modeling framework involving two levels of accident severity. With regard to the highest class (Interstates), the results suggest that, compared to no-casualty accidents, casualty accidents are more sensitive to traffic volume and average vertical grade, but less sensitive to the inside shoulder width and the median width. For US Roads, it was determined that, compared to no-casualty accidents, casualty accidents are more sensitive to traffic volume, outside shoulder width, pavement condition, and median width but less sensitive to the average vertical grade. For the relatively lowest-class roads (State Roads), it was determined that, compared to no-casualty accidents, casualty accidents are more sensitive to the traffic volume, lane width, outside shoulder width, and pavement condition. Compared to the relatively lower-class highways, accidents at higher-class highways are more sensitive to: changes in traffic volume, average vertical grade, median width, inside shoulder width, and the pavement condition (no-casualty accidents only); but less sensitive to changes in lane width, pavement condition (casualty accidents only), and the outside shoulder width. This variation in sensitivity across the different road classes could be attributed to the differences in road geometry standards across the road classes, as the results seem to support the hypothesis that these standards strongly influence accident occurrence. It is hoped that the developed bivariate negative binomial models can help highway engineers to evaluate their current design standards and policy, and to assess the safety consequences of changes in these standards in each road class.

ACS Style

Sikai Chen; Tariq Usman Saeed; Majed Alinizzi; Steven Lavrenz; Samuel Labi. Safety sensitivity to roadway characteristics: A comparison across highway classes. Accident Analysis & Prevention 2018, 123, 39 -50.

AMA Style

Sikai Chen, Tariq Usman Saeed, Majed Alinizzi, Steven Lavrenz, Samuel Labi. Safety sensitivity to roadway characteristics: A comparison across highway classes. Accident Analysis & Prevention. 2018; 123 ():39-50.

Chicago/Turabian Style

Sikai Chen; Tariq Usman Saeed; Majed Alinizzi; Steven Lavrenz; Samuel Labi. 2018. "Safety sensitivity to roadway characteristics: A comparison across highway classes." Accident Analysis & Prevention 123, no. : 39-50.

Journal article
Published: 01 September 2018 in Infrastructure Asset Management
Reads 0
Downloads 0

Through effective and proactive monitoring, highway agencies can acquire information needed for deck repair or replacement timing decisions. However, system-wide monitoring of infrastructure requires a large expenditure outlay and therefore needs to be justified by comparing its costs to the potential savings if such monitoring leads to timely actions. This paper presents a framework that considers two strategies for managing a bridge deck network: a condition-based strategy that involves monitoring and repair and a time-based strategy that involves repairs at specific time intervals without condition monitoring. Using a case study, the paper calculates the life-cycle cost of each strategy as the sum of the monitoring and repair costs. The paper estimates that if a non-destructive test (NDT) is used as the monitoring platform system-wide, the unit monitoring cost will be $0·04–0·35/ft2 ($0·43–3·77/m2) of deck (average $0·22/ft2 ($2·37/m2)). This cost is expected to be different for other inventories due to differences in age, inventory size and bridge proximities. The paper determines that the NDT monitoring programme benefits outweigh its costs ($3·68–10·42 rate of return in repair savings for every dollar of investment in that programme). The paper also analyses the sensitivity of the outcome to key evaluation factors.

ACS Style

Benjamin Taylor; Yu Qiao; Mark Bowman; Samuel Labi. Feasibility of long-term NDT programme for system-wide monitoring of bridge deck condition in Indiana, USA. Infrastructure Asset Management 2018, 5, 105 -117.

AMA Style

Benjamin Taylor, Yu Qiao, Mark Bowman, Samuel Labi. Feasibility of long-term NDT programme for system-wide monitoring of bridge deck condition in Indiana, USA. Infrastructure Asset Management. 2018; 5 (3):105-117.

Chicago/Turabian Style

Benjamin Taylor; Yu Qiao; Mark Bowman; Samuel Labi. 2018. "Feasibility of long-term NDT programme for system-wide monitoring of bridge deck condition in Indiana, USA." Infrastructure Asset Management 5, no. 3: 105-117.

Journal article
Published: 01 September 2018 in Infrastructure Asset Management
Reads 0
Downloads 0
ACS Style

Samuel Labi; Tariq Usman Saeed; Asif Faiz. Editorial. Infrastructure Asset Management 2018, 5, 75 -76.

AMA Style

Samuel Labi, Tariq Usman Saeed, Asif Faiz. Editorial. Infrastructure Asset Management. 2018; 5 (3):75-76.

Chicago/Turabian Style

Samuel Labi; Tariq Usman Saeed; Asif Faiz. 2018. "Editorial." Infrastructure Asset Management 5, no. 3: 75-76.

Report
Published: 31 July 2018 in Effects of Bridge Surface and Pavement Maintenance Activities on Asset Rating
Reads 0
Downloads 0
ACS Style

Tariq Usman Saeed; Yu Qiao; Sikai Chen; Saeed Alqadhi; Zhibo Zhang; Samuel Labi; Kumares C. Sinha. Effects of Bridge Surface and Pavement Maintenance Activities on Asset Rating. Effects of Bridge Surface and Pavement Maintenance Activities on Asset Rating 2018, 1 .

AMA Style

Tariq Usman Saeed, Yu Qiao, Sikai Chen, Saeed Alqadhi, Zhibo Zhang, Samuel Labi, Kumares C. Sinha. Effects of Bridge Surface and Pavement Maintenance Activities on Asset Rating. Effects of Bridge Surface and Pavement Maintenance Activities on Asset Rating. 2018; ():1.

Chicago/Turabian Style

Tariq Usman Saeed; Yu Qiao; Sikai Chen; Saeed Alqadhi; Zhibo Zhang; Samuel Labi; Kumares C. Sinha. 2018. "Effects of Bridge Surface and Pavement Maintenance Activities on Asset Rating." Effects of Bridge Surface and Pavement Maintenance Activities on Asset Rating , no. : 1.

Research article
Published: 27 June 2018 in Journal of Advanced Transportation
Reads 0
Downloads 0

Vertical alignment, which includes vertical grades and lengths, is a critical aspect of highway design policy that influences safety. A full understanding of the effect of vertical grade and segment length on highway safety can help agencies to evaluate or adjust their design policies regarding vertical alignment design features (grade and length). For this reason, it is useful to assess the current relationships between design policy and safety performance. To address this task, this paper uses data from interstate segments to first establish the relationship between these design features and safety. Safety is expressed in terms of the three different levels of crash severity (fatal, injury, and property damage only). In its analysis, the paper departs from the traditional univariate models (where each crash severity is modeled separately) and instead uses a seemingly unrelated negative binomial (SUNB) technique, a multivariate model that duly accounts for the unobserved shared effects between the different levels of crash severity. In addition, the paper’s models duly recognize and account for the holistic nature of the grade and tangent length effects: the effect of the sum (interaction) of the vertical grade and length is different from the sum of their individual effects. The paper investigates the relationships for rural and urban interstate highway segments. Against the background of the developed models, the paper evaluates current design policies (specifications on vertical alignment grade and length) for similar classes of highways at a number of countries and presents a set of nomograms that feature lines representing points of equal safety performance. These charts can be used by the highway agencies to evaluate and compare their current or possible future highway design policies.

ACS Style

Zongxin Tang; Sikai Chen; Jianchuan Cheng; Seyed Ali Ghahari; Samuel Labi. Highway Design and Safety Consequences: A Case Study of Interstate Highway Vertical Grades. Journal of Advanced Transportation 2018, 2018, 1 -13.

AMA Style

Zongxin Tang, Sikai Chen, Jianchuan Cheng, Seyed Ali Ghahari, Samuel Labi. Highway Design and Safety Consequences: A Case Study of Interstate Highway Vertical Grades. Journal of Advanced Transportation. 2018; 2018 ():1-13.

Chicago/Turabian Style

Zongxin Tang; Sikai Chen; Jianchuan Cheng; Seyed Ali Ghahari; Samuel Labi. 2018. "Highway Design and Safety Consequences: A Case Study of Interstate Highway Vertical Grades." Journal of Advanced Transportation 2018, no. : 1-13.