Pub Date : 2024-06-03DOI: 10.1177/03611981241243080
Mohammadhadi Mansourianfar, Ziyuan Gu, M. Saberi
The interaction between mixed autonomy traffic and public transport vehicles competing for limited road space is a less explored area of research. To evaluate the traffic dynamics in bimodal networks, a three-dimensional (passenger) network fundamental diagram, known as 3D-NFD (3D-pNFD), can be estimated that relates the accumulation of cars (autonomous and human-driven) and buses to the network vehicular (passenger) travel production. In this study, we propose a 3D-pNFD-based congestion pricing scheme considering three vehicle classes of buses, system-optimal (SO) seeking connected and automated vehicles (CAVs), and user-equilibrium (UE) seeking human-driven vehicles (HVs). We develop an iterative tri-level modeling framework for mode choice, pricing, and route choice in a mixed autonomy network. The lower level generates mixed equilibrium traffic flow through an integrated mixed equilibrium simulation-based dynamic traffic assignment model and a transit assignment model. The mid-level finds the optimal toll rates through a 3D-pNFD feedback-based controller. A nested logit-based mode choice model is also applied to capture travelers’ preferences toward three available modes and incorporates elastic demand. To encourage CAVs to follow the SO routing mode, they are provided with a discount on the congestion toll whereas UE-seeking HVs are subject to full price toll. Buses are also entirely exempt from the toll. We explore three scenarios with different discount rates on SO-seeking CAVs to investigate the effect of the incentive plans on the mode choice behaviors of road users in the pricing zone. The performance of the proposed model is evaluated in a large-scale network in Melbourne, Australia.
混合自主交通与公共交通车辆争夺有限道路空间之间的相互作用是一个探索较少的研究领域。为了评估双模网络中的交通动态，可以估算出三维（乘客）网络基本图，即三维-NFD（3D-pNFD），它将小汽车（自动驾驶和人工驾驶）和公交车的积累与网络车辆（乘客）出行产量联系起来。在本研究中，我们提出了一种基于 3D-pNFD 的拥堵定价方案，该方案考虑了公交车、寻求系统最优（SO）的互联和自动驾驶车辆（CAVs）以及寻求用户均衡（UE）的人工驾驶车辆（HVs）这三种车辆类别。我们为混合自动驾驶网络中的模式选择、定价和路线选择开发了一个三层迭代建模框架。下层通过基于混合平衡模拟的动态交通分配模型和公交分配模型生成混合平衡交通流。中层通过基于 3D-pNFD 反馈的控制器找到最佳收费率。此外，还采用基于嵌套 logit 的模式选择模型来捕捉旅客对三种可用模式的偏好，并将弹性需求纳入其中。为鼓励 CAV 采用 SO 路线模式，为其提供了拥堵费折扣，而寻求 UE 的 HV 则需支付全价通行费。巴士也完全免收通行费。我们探讨了三种对寻求 SO 的 CAV 采用不同折扣率的方案，以研究激励计划对收费区内道路使用者模式选择行为的影响。我们在澳大利亚墨尔本的一个大型网络中对所提议模型的性能进行了评估。
{"title":"Joint Routing and Pricing Control in Bimodal Mixed Autonomy Networks with Elastic Demand and Three-Dimensional Passenger Macroscopic Fundamental Diagram","authors":"Mohammadhadi Mansourianfar, Ziyuan Gu, M. Saberi","doi":"10.1177/03611981241243080","DOIUrl":"https://doi.org/10.1177/03611981241243080","url":null,"abstract":"The interaction between mixed autonomy traffic and public transport vehicles competing for limited road space is a less explored area of research. To evaluate the traffic dynamics in bimodal networks, a three-dimensional (passenger) network fundamental diagram, known as 3D-NFD (3D-pNFD), can be estimated that relates the accumulation of cars (autonomous and human-driven) and buses to the network vehicular (passenger) travel production. In this study, we propose a 3D-pNFD-based congestion pricing scheme considering three vehicle classes of buses, system-optimal (SO) seeking connected and automated vehicles (CAVs), and user-equilibrium (UE) seeking human-driven vehicles (HVs). We develop an iterative tri-level modeling framework for mode choice, pricing, and route choice in a mixed autonomy network. The lower level generates mixed equilibrium traffic flow through an integrated mixed equilibrium simulation-based dynamic traffic assignment model and a transit assignment model. The mid-level finds the optimal toll rates through a 3D-pNFD feedback-based controller. A nested logit-based mode choice model is also applied to capture travelers’ preferences toward three available modes and incorporates elastic demand. To encourage CAVs to follow the SO routing mode, they are provided with a discount on the congestion toll whereas UE-seeking HVs are subject to full price toll. Buses are also entirely exempt from the toll. We explore three scenarios with different discount rates on SO-seeking CAVs to investigate the effect of the incentive plans on the mode choice behaviors of road users in the pricing zone. The performance of the proposed model is evaluated in a large-scale network in Melbourne, Australia.","PeriodicalId":309251,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141270267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-03DOI: 10.1177/03611981241252146
Hong Zhang, Linbiao Chen, Xijun Zhang, Jie Cao
Traffic flow forecasting is the foundation of the dynamic control and application of intelligent transportation systems (ITS). It is also of significant practical value in alleviating road congestion. Given the periodic and dynamic changes in traffic flow and the spatiotemporal coupling interaction of complex road networks, traffic flow forecasting is challenging and rarely yields satisfactory prediction results. To capture the dynamic spatiotemporal characteristics of traffic flow, a new model of traffic flow forecasting based on spatiotemporal convolution and probabilistic sparse self-attention (STC-PSSA) is proposed. It consists of a spatiotemporal graph convolution network (ST-GCN) module, a spatiotemporal convolution module (ST-Conv), and a probabilistic sparse attention module (PSSA). ST-GCN consists of the gated temporal convolutional network (G-TCN) and the graph convolution network (GCN), which are used to capture the temporal dependence and spatial correlation of the traffic flow, respectively. Multiple ST-GCNs are stacked to handle spatial features at various time levels. The ST-Conv captures intricate temporal dependence at the same location and dynamic spatial features at neighboring locations simultaneously. The PSSA combines dynamic spatiotemporal features and performs long-term forecasting efficiently. The experimental results demonstrate that the STC-PSSA model can accurately extract the dynamic spatiotemporal characteristics of traffic flow and outperforms the popular baseline methods in forecasting accuracy.
{"title":"STC-PSSA: A New Model of Traffic Flow Forecasting Based on Spatiotemporal Convolution and Probabilistic Sparse Self-Attention","authors":"Hong Zhang, Linbiao Chen, Xijun Zhang, Jie Cao","doi":"10.1177/03611981241252146","DOIUrl":"https://doi.org/10.1177/03611981241252146","url":null,"abstract":"Traffic flow forecasting is the foundation of the dynamic control and application of intelligent transportation systems (ITS). It is also of significant practical value in alleviating road congestion. Given the periodic and dynamic changes in traffic flow and the spatiotemporal coupling interaction of complex road networks, traffic flow forecasting is challenging and rarely yields satisfactory prediction results. To capture the dynamic spatiotemporal characteristics of traffic flow, a new model of traffic flow forecasting based on spatiotemporal convolution and probabilistic sparse self-attention (STC-PSSA) is proposed. It consists of a spatiotemporal graph convolution network (ST-GCN) module, a spatiotemporal convolution module (ST-Conv), and a probabilistic sparse attention module (PSSA). ST-GCN consists of the gated temporal convolutional network (G-TCN) and the graph convolution network (GCN), which are used to capture the temporal dependence and spatial correlation of the traffic flow, respectively. Multiple ST-GCNs are stacked to handle spatial features at various time levels. The ST-Conv captures intricate temporal dependence at the same location and dynamic spatial features at neighboring locations simultaneously. The PSSA combines dynamic spatiotemporal features and performs long-term forecasting efficiently. The experimental results demonstrate that the STC-PSSA model can accurately extract the dynamic spatiotemporal characteristics of traffic flow and outperforms the popular baseline methods in forecasting accuracy.","PeriodicalId":309251,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141270306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-23DOI: 10.1177/03611981241243330
Jagan Gudimettla, Josh Brinegar, Mike Praul, Jim Grove, Bob Conway
Many states are currently in the process of evaluating the use of surface resistivity (SR) or bulk resistivity (BR) tests to assess permeability of concrete in lieu of the standard test method for electrical indication of concrete’s ability to resist chloride ion penetration (AASHTO T 277 and ASTM C1202) which is commonly referred to as the rapid chloride permeability test (RCPT). A few states, such as Louisiana and Maine, implemented resistivity testing in their specifications many years ago. As with any test method implementation, it is important to learn from data generated and experience gained to further refine the specifications in respect of both testing protocols and the specification limits. In this paper, the Federal Highway Administration’s Mobile Concrete Technology Center SR and BR data from 30 field projects in 25 states is analyzed to provide information that could be helpful to agencies as they specify or improve their specifications with respect to resistivity testing. This paper attempts to answer questions related to 1) change in resistivity testing results with age, 2) range and variability of resistivity data from mainline paving mixtures, 3) comparison of test results between SR and BR data, 4) comparison of resistivity data gathered with equipment from various vendors, and 5) use of 28 versus 56 day data.
{"title":"Answers to Your Resistivity Questions and Helpful Findings to Develop a Robust Resistivity Specification","authors":"Jagan Gudimettla, Josh Brinegar, Mike Praul, Jim Grove, Bob Conway","doi":"10.1177/03611981241243330","DOIUrl":"https://doi.org/10.1177/03611981241243330","url":null,"abstract":"Many states are currently in the process of evaluating the use of surface resistivity (SR) or bulk resistivity (BR) tests to assess permeability of concrete in lieu of the standard test method for electrical indication of concrete’s ability to resist chloride ion penetration (AASHTO T 277 and ASTM C1202) which is commonly referred to as the rapid chloride permeability test (RCPT). A few states, such as Louisiana and Maine, implemented resistivity testing in their specifications many years ago. As with any test method implementation, it is important to learn from data generated and experience gained to further refine the specifications in respect of both testing protocols and the specification limits. In this paper, the Federal Highway Administration’s Mobile Concrete Technology Center SR and BR data from 30 field projects in 25 states is analyzed to provide information that could be helpful to agencies as they specify or improve their specifications with respect to resistivity testing. This paper attempts to answer questions related to 1) change in resistivity testing results with age, 2) range and variability of resistivity data from mainline paving mixtures, 3) comparison of test results between SR and BR data, 4) comparison of resistivity data gathered with equipment from various vendors, and 5) use of 28 versus 56 day data.","PeriodicalId":309251,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141103450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-23DOI: 10.1177/03611981241246270
Dongbo Peng, Guoyuan Wu, K. Boriboonsomsin
The battery electric truck (BET) has emerged as a promising solution to reduce greenhouse gas emissions in urban logistics, given the current strict environmental regulations. This research explores the formulation and solution of the bi-objective BET dispatching problem with backhauls and time windows, aiming to simultaneously reduce environmental impacts and enhance the efficiency of urban logistics. From the sustainability perspective, one of the objectives is to minimize total energy costs, which include energy consumption and battery replacement expenses. On the other hand, from an economic perspective, the other objective is the minimization of labor costs. To solve this bi-objective BET dispatching problem, we propose an innovative approach, integrating an adaptive large neighborhood search-based metaheuristics algorithm with a multi-objective optimization strategy. This integration enables the exploration of the trade-off between fleet energy expenses and labor costs, optimizing the dispatching decisions for BETs. To validate the proposed dispatching strategy, extensive experiments were conducted using real-world fleet operations data from a logistics fleet in Southern California. The results demonstrated that the proposed approach yields a set of Pareto solutions, showcasing its effectiveness in finding a balance between energy efficiency and labor costs in urban logistics systems. The findings of this research contribute to advancing sustainable urban logistics practices and provide valuable insights for fleet operators in effectively managing BET fleets to reduce environmental impacts while maintaining economic efficiency.
鉴于当前严格的环境法规，电池电动卡车（BET）已成为城市物流中减少温室气体排放的一种有前途的解决方案。本研究探讨了带有回程和时间窗口的双目标 BET 调度问题的提出和解决方法，旨在同时减少对环境的影响和提高城市物流的效率。从可持续发展的角度来看，目标之一是最大限度地降低总能源成本，其中包括能源消耗和电池更换费用。另一方面，从经济角度来看，另一个目标是最大限度地降低劳动力成本。为了解决这个双目标 BET 调度问题，我们提出了一种创新方法，将基于大邻域搜索的自适应元启发式算法与多目标优化策略相结合。通过这种整合，可以探索车队能源支出和劳动力成本之间的权衡，优化 BET 的调度决策。为了验证所提出的调度策略，我们使用南加州物流车队的实际车队运营数据进行了大量实验。结果表明，所提出的方法产生了一组帕累托解决方案，展示了其在城市物流系统中寻求能源效率和劳动力成本之间平衡的有效性。这项研究成果有助于推进可持续城市物流实践，并为车队运营商有效管理 BET 车队提供了宝贵的见解，从而在保持经济效益的同时减少对环境的影响。
{"title":"Bi-Objective Battery Electric Truck Dispatching Problem with Backhauls and Time Windows","authors":"Dongbo Peng, Guoyuan Wu, K. Boriboonsomsin","doi":"10.1177/03611981241246270","DOIUrl":"https://doi.org/10.1177/03611981241246270","url":null,"abstract":"The battery electric truck (BET) has emerged as a promising solution to reduce greenhouse gas emissions in urban logistics, given the current strict environmental regulations. This research explores the formulation and solution of the bi-objective BET dispatching problem with backhauls and time windows, aiming to simultaneously reduce environmental impacts and enhance the efficiency of urban logistics. From the sustainability perspective, one of the objectives is to minimize total energy costs, which include energy consumption and battery replacement expenses. On the other hand, from an economic perspective, the other objective is the minimization of labor costs. To solve this bi-objective BET dispatching problem, we propose an innovative approach, integrating an adaptive large neighborhood search-based metaheuristics algorithm with a multi-objective optimization strategy. This integration enables the exploration of the trade-off between fleet energy expenses and labor costs, optimizing the dispatching decisions for BETs. To validate the proposed dispatching strategy, extensive experiments were conducted using real-world fleet operations data from a logistics fleet in Southern California. The results demonstrated that the proposed approach yields a set of Pareto solutions, showcasing its effectiveness in finding a balance between energy efficiency and labor costs in urban logistics systems. The findings of this research contribute to advancing sustainable urban logistics practices and provide valuable insights for fleet operators in effectively managing BET fleets to reduce environmental impacts while maintaining economic efficiency.","PeriodicalId":309251,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141104927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-23DOI: 10.1177/03611981241249743
Phuong H.D. Nguyen, Daniel Tran, Sid Scott, Linda Konrath
Alternative contracting methods (ACMs) have been increasingly used for airport capital construction projects to explore the opportunity for achieving better cost and time savings than traditional design-bid-build. Progressive design-build (PDB), an emerging variation of design-build, stands out as a promising delivery method that promotes collaboration between project stakeholders. Although PDB has been successfully used across building, water/wastewater, and transit construction sectors, its implementation in the aviation industry is still limited because of legislative considerations, regulatory policies, and funding constraints. A research gap exists in systematically investigating current practices in implementing PDB in airport projects. The main objective of this study is to explore the selection criteria, implementation strategies, success factors, and lessons learned from using PDB for airport capital construction projects. This study employed a triangulation research methodology, including a comprehensive review of PDB guidance and manuals, an industry survey of 39 airports across the U.S., and structured interviews with 12 airport representatives. This study found that the top four criteria for selecting PDB are: flexibility to handle complexity, reducing claims, industry input on constructability, and cost control. The main benefits of using PDB for airport construction projects include improving project schedules, enhancing design control levels, and better management of project complexity and risks. This study contributes to the body of knowledge by providing insights into the current PDB practices for airport capital projects. Lessons learned from implementing PDB can help airport authorities and owners better administer and manage their projects.
{"title":"Implementation of Progressive Design-Build in Airport Capital Construction Projects","authors":"Phuong H.D. Nguyen, Daniel Tran, Sid Scott, Linda Konrath","doi":"10.1177/03611981241249743","DOIUrl":"https://doi.org/10.1177/03611981241249743","url":null,"abstract":"Alternative contracting methods (ACMs) have been increasingly used for airport capital construction projects to explore the opportunity for achieving better cost and time savings than traditional design-bid-build. Progressive design-build (PDB), an emerging variation of design-build, stands out as a promising delivery method that promotes collaboration between project stakeholders. Although PDB has been successfully used across building, water/wastewater, and transit construction sectors, its implementation in the aviation industry is still limited because of legislative considerations, regulatory policies, and funding constraints. A research gap exists in systematically investigating current practices in implementing PDB in airport projects. The main objective of this study is to explore the selection criteria, implementation strategies, success factors, and lessons learned from using PDB for airport capital construction projects. This study employed a triangulation research methodology, including a comprehensive review of PDB guidance and manuals, an industry survey of 39 airports across the U.S., and structured interviews with 12 airport representatives. This study found that the top four criteria for selecting PDB are: flexibility to handle complexity, reducing claims, industry input on constructability, and cost control. The main benefits of using PDB for airport construction projects include improving project schedules, enhancing design control levels, and better management of project complexity and risks. This study contributes to the body of knowledge by providing insights into the current PDB practices for airport capital projects. Lessons learned from implementing PDB can help airport authorities and owners better administer and manage their projects.","PeriodicalId":309251,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141107994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-23DOI: 10.1177/03611981241246989
Weiqi Wang, James Roberts, Prasad Rangaraju
The growing scarcity of conventional supplementary cementitious materials (SCMs) such as Class F, Class C fly ashes, and slag has necessitated exploring alternative SCMs previously considered suboptimal. In particular, high-alkali SCMs are often avoided because of the potential concern that their alkali content could release into the concrete pore solution, thus exacerbating the potential for alkali-silica reaction (ASR). However, preliminary research indicates that not all high-alkali SCMs are deleterious, and some can effectively suppress the ASR expansive reaction when used in sufficient dosage levels. This study evaluates the feasibility of using high-alkali SCMs, such as high-alkali natural pozzolans and reclaimed fly ashes, focusing on their pozzolanic reactivity and the correlation between the reactivity and their ASR mitigation performance. The pozzolanic reactivity of the SCMs was evaluated by the R3 test per ASTM C1897 and strength activity index test per ASTM C311. Thermogravimetric analysis was used to determine the calcium hydroxide consumption by the SCMs. ASR mitigation performance of SCMs was evaluated in accordance with American Association of State Highway and Transportation Officials (AASHTO) T380 miniature concrete prism test. Additionally, pore solution expression and analysis of paste specimens were conducted to determine the correlation between the total alkali and the released alkali levels into the pore solution. Based on the results of this study, all SCMs indicated high pozzolanic reactivity; however, individual performance varied by test method. Ultimately, the high-alkali SCMs, particularly natural pozzolans, did not appear to release any significant levels of alkalis into the pore solution readily and, therefore, show potential for ASR mitigation when used in sufficient dosage levels.
由于 F 级、C 级粉煤灰和矿渣等传统胶凝补充材料 (SCM) 越来越少，因此有必要探索以前被认为是次优的替代 SCM。尤其是高碱 SCM，由于其碱含量可能会释放到混凝土孔隙溶液中，从而加剧碱硅反应（ASR）的可能性，因此经常被避免使用。不过，初步研究表明，并非所有高碱 SCM 都会造成危害，有些高碱 SCM 在使用足够剂量的情况下可以有效抑制 ASR 膨胀反应。本研究评估了使用高碱 SCM（如高碱天然毛细管和再生粉煤灰）的可行性，重点关注其毛细管反应性以及反应性与 ASR 缓解性能之间的相关性。根据 ASTM C1897 进行的 R3 试验和根据 ASTM C311 进行的强度活性指数试验评估了单质材料的热分解反应性。热重分析用于确定 SCM 的氢氧化钙消耗量。根据美国州公路和交通官员协会 (AASHTO) T380 微型混凝土棱柱测试，对 SCM 的 ASR 缓解性能进行了评估。此外，还进行了孔隙溶液表达和糊状试样分析，以确定总碱和释放到孔隙溶液中的碱含量之间的相关性。根据这项研究的结果，所有单质材料都显示出较高的胶凝反应活性；但是，不同测试方法的单质材料性能各不相同。最终，高碱 SCM（尤其是天然毛细管）似乎不会轻易向孔隙溶液中释放大量碱，因此，在使用足够的剂量水平时，具有减轻 ASR 的潜力。
{"title":"Pozzolanic Reactivity of High-Alkali Supplementary Cementitious Materials and Its Impact on Mitigation of Alkali-Silica Reaction","authors":"Weiqi Wang, James Roberts, Prasad Rangaraju","doi":"10.1177/03611981241246989","DOIUrl":"https://doi.org/10.1177/03611981241246989","url":null,"abstract":"The growing scarcity of conventional supplementary cementitious materials (SCMs) such as Class F, Class C fly ashes, and slag has necessitated exploring alternative SCMs previously considered suboptimal. In particular, high-alkali SCMs are often avoided because of the potential concern that their alkali content could release into the concrete pore solution, thus exacerbating the potential for alkali-silica reaction (ASR). However, preliminary research indicates that not all high-alkali SCMs are deleterious, and some can effectively suppress the ASR expansive reaction when used in sufficient dosage levels. This study evaluates the feasibility of using high-alkali SCMs, such as high-alkali natural pozzolans and reclaimed fly ashes, focusing on their pozzolanic reactivity and the correlation between the reactivity and their ASR mitigation performance. The pozzolanic reactivity of the SCMs was evaluated by the R3 test per ASTM C1897 and strength activity index test per ASTM C311. Thermogravimetric analysis was used to determine the calcium hydroxide consumption by the SCMs. ASR mitigation performance of SCMs was evaluated in accordance with American Association of State Highway and Transportation Officials (AASHTO) T380 miniature concrete prism test. Additionally, pore solution expression and analysis of paste specimens were conducted to determine the correlation between the total alkali and the released alkali levels into the pore solution. Based on the results of this study, all SCMs indicated high pozzolanic reactivity; however, individual performance varied by test method. Ultimately, the high-alkali SCMs, particularly natural pozzolans, did not appear to release any significant levels of alkalis into the pore solution readily and, therefore, show potential for ASR mitigation when used in sufficient dosage levels.","PeriodicalId":309251,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141103199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-23DOI: 10.1177/03611981241248652
Junqing Wang, Mecit Cetin, Hong Yang, Kun Xie, Guocong Zhai, Sherif Ishak
Safety service patrols (SSPs) play an important role in incident management on highways. It is critical to respond to incidents in a timely manner as this can significantly reduce nonrecurrent congestion and improve safety. Therefore, it is essential to allocate available SSP vehicles to highway segments such that their effectiveness is maximized. This study aimed to develop a simulation-based framework to assist with SSP service optimization. More specifically, a discrete event-based simulation tool (i.e., SSP-OPT) with customizable parameters was developed to help plan the optimum patrol routes based on available SSP resources and predicted incidents. The developed tool was tested with roadway traffic and incident data from the Virginia highway network. After model calibration, the simulation results showed that the developed SSP-OPT tool could replicate the patrol routes with similar performance to the field observations, validating the tool. Further, adopting the tool for corridor-level optimization could help to identify the best patrol plan to minimize SSP response time and maximize SSP response rates for a given number of SSP vehicles. The SSP-OPT tool requires minimal user input (e.g., segment lengths, annual average daily traffic) and has the flexibility to be easily applied to any highway corridor once calibrated. The tool generates various performance metrics to enable more informed decision making in SSP route planning.
{"title":"Improving Effectiveness of the Safety Service Patrol Programs: A Discrete Event-Based Simulation Approach","authors":"Junqing Wang, Mecit Cetin, Hong Yang, Kun Xie, Guocong Zhai, Sherif Ishak","doi":"10.1177/03611981241248652","DOIUrl":"https://doi.org/10.1177/03611981241248652","url":null,"abstract":"Safety service patrols (SSPs) play an important role in incident management on highways. It is critical to respond to incidents in a timely manner as this can significantly reduce nonrecurrent congestion and improve safety. Therefore, it is essential to allocate available SSP vehicles to highway segments such that their effectiveness is maximized. This study aimed to develop a simulation-based framework to assist with SSP service optimization. More specifically, a discrete event-based simulation tool (i.e., SSP-OPT) with customizable parameters was developed to help plan the optimum patrol routes based on available SSP resources and predicted incidents. The developed tool was tested with roadway traffic and incident data from the Virginia highway network. After model calibration, the simulation results showed that the developed SSP-OPT tool could replicate the patrol routes with similar performance to the field observations, validating the tool. Further, adopting the tool for corridor-level optimization could help to identify the best patrol plan to minimize SSP response time and maximize SSP response rates for a given number of SSP vehicles. The SSP-OPT tool requires minimal user input (e.g., segment lengths, annual average daily traffic) and has the flexibility to be easily applied to any highway corridor once calibrated. The tool generates various performance metrics to enable more informed decision making in SSP route planning.","PeriodicalId":309251,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141107788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-23DOI: 10.1177/03611981241247168
Zhe Zheng, Kun An, Zicheng Su, Nan Zheng, Wanjing Ma
This paper presents an integrated optimal controller for the tandem intersection with lane function design and signal control, aiming to improve intersection efficiency and service reliability with a multi-objective formulation. The tandem intersection is a type of unconventional intersection that can re-organize the vehicles at entrance lanes with sorting areas, and improve intersection capacity through the coordination of pre-signals and main signals. However, most existing studies related to tandem intersection control assume that the lane functions in the sorting areas for both the through and left-turn movements are the same, and the traffic demand remains static. To fill these gaps, this paper first identifies six different tandem control modes based on the different lane functions and phase sequence schemes in the sorting area, and the corresponding delay models for each mode are derived. Furthermore, an integrated optimization model is developed to minimize the mean and semistandard deviation of the intersection delay, and the Non-dominated Sorting Genetic Algorithm-II is used to obtain the optimal solution. A case study is conducted in a real-world intersection in Melbourne, Australia, under various traffic conditions. The results show that the proposed method can decrease average delay and queue length by 19.61% and 20.94%, respectively, compared with conventional intersection design.
{"title":"Integrated Optimization Model of Lane Function and Signal Control for Tandem Intersections","authors":"Zhe Zheng, Kun An, Zicheng Su, Nan Zheng, Wanjing Ma","doi":"10.1177/03611981241247168","DOIUrl":"https://doi.org/10.1177/03611981241247168","url":null,"abstract":"This paper presents an integrated optimal controller for the tandem intersection with lane function design and signal control, aiming to improve intersection efficiency and service reliability with a multi-objective formulation. The tandem intersection is a type of unconventional intersection that can re-organize the vehicles at entrance lanes with sorting areas, and improve intersection capacity through the coordination of pre-signals and main signals. However, most existing studies related to tandem intersection control assume that the lane functions in the sorting areas for both the through and left-turn movements are the same, and the traffic demand remains static. To fill these gaps, this paper first identifies six different tandem control modes based on the different lane functions and phase sequence schemes in the sorting area, and the corresponding delay models for each mode are derived. Furthermore, an integrated optimization model is developed to minimize the mean and semistandard deviation of the intersection delay, and the Non-dominated Sorting Genetic Algorithm-II is used to obtain the optimal solution. A case study is conducted in a real-world intersection in Melbourne, Australia, under various traffic conditions. The results show that the proposed method can decrease average delay and queue length by 19.61% and 20.94%, respectively, compared with conventional intersection design.","PeriodicalId":309251,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141103567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-23DOI: 10.1177/03611981241246973
Victoria Dahmen, S. Weikl, K. Bogenberger
Mode choice modeling is imperative for predicting and understanding travel behavior. For this purpose, machine learning (ML) models have increasingly been applied to stated preference and traditional self-recorded revealed preference data with promising results, particularly for extreme gradient boosting (XGBoost) and random forest (RF) models. Because of the rise in the use of tracking-based smartphone applications for recording travel behavior, we address the important and unprecedented task of testing these ML models for mode choice modeling on such data. Furthermore, as ML approaches are still criticized for leading to results that are hard to understand, we consider it essential to provide an in-depth interpretability analysis of the best-performing model. Our results show that the XGBoost and RF models far outperform a conventional multinomial logit model, both overall and for each mode. The interpretability analysis using the Shapley additive explanations approach reveals that the XGBoost model can be explained well at the overall and mode level. In addition, we demonstrate how to analyze individual predictions. Lastly, a sensitivity analysis gives insight into the relative importance of different data sources, sample size, and user involvement. We conclude that the XGBoost model performs best, while also being explainable. Insights generated by such models can be used, for instance, to predict mode choice decisions for arbitrary origin–destination pairs to see which impacts infrastructural changes would have on the mode share.
模式选择建模对于预测和理解旅行行为至关重要。为此，越来越多的机器学习（ML）模型被应用于陈述偏好和传统的自我记录揭示偏好数据，尤其是极端梯度提升（XGBoost）和随机森林（RF）模型，并取得了可喜的成果。由于使用基于跟踪的智能手机应用程序来记录出行行为的情况日益增多，我们将在此类数据上测试这些用于模式选择建模的 ML 模型，这是一项前所未有的重要任务。此外，由于 ML 方法仍然被批评为导致难以理解的结果，我们认为对表现最佳的模型进行深入的可解释性分析是非常必要的。我们的结果表明，XGBoost 和 RF 模型无论在整体上还是在每种模式上都远远优于传统的多二项 logit 模型。使用 Shapley 加法解释方法进行的可解释性分析表明，XGBoost 模型在整体和模式层面都能得到很好的解释。此外，我们还演示了如何分析单个预测。最后，通过敏感性分析，我们了解了不同数据源、样本大小和用户参与的相对重要性。我们得出的结论是，XGBoost 模型表现最佳，同时也具有可解释性。例如，此类模型产生的洞察力可用于预测任意出发地-目的地对的模式选择决策，以了解基础设施的变化会对模式共享产生哪些影响。
{"title":"Interpretable Machine Learning for Mode Choice Modeling on Tracking-Based Revealed Preference Data","authors":"Victoria Dahmen, S. Weikl, K. Bogenberger","doi":"10.1177/03611981241246973","DOIUrl":"https://doi.org/10.1177/03611981241246973","url":null,"abstract":"Mode choice modeling is imperative for predicting and understanding travel behavior. For this purpose, machine learning (ML) models have increasingly been applied to stated preference and traditional self-recorded revealed preference data with promising results, particularly for extreme gradient boosting (XGBoost) and random forest (RF) models. Because of the rise in the use of tracking-based smartphone applications for recording travel behavior, we address the important and unprecedented task of testing these ML models for mode choice modeling on such data. Furthermore, as ML approaches are still criticized for leading to results that are hard to understand, we consider it essential to provide an in-depth interpretability analysis of the best-performing model. Our results show that the XGBoost and RF models far outperform a conventional multinomial logit model, both overall and for each mode. The interpretability analysis using the Shapley additive explanations approach reveals that the XGBoost model can be explained well at the overall and mode level. In addition, we demonstrate how to analyze individual predictions. Lastly, a sensitivity analysis gives insight into the relative importance of different data sources, sample size, and user involvement. We conclude that the XGBoost model performs best, while also being explainable. Insights generated by such models can be used, for instance, to predict mode choice decisions for arbitrary origin–destination pairs to see which impacts infrastructural changes would have on the mode share.","PeriodicalId":309251,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141107830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-05-23DOI: 10.1177/03611981241242068
Enyan Zhu, Jian Yao, Wenjia Zheng, Chang Sun, Mei Sha
With the growing dependence of human beings on the logistics industry, the trend of logistics carbon emissions (LCEs) growth has become much more serious. To investigate the spatial-temporal pattern of LCEs as well as their driving factors, city-scale LCEs were calculated by combining them with nighttime light remote sensing data. In addition, a spatial panel data model was applied in the case of China’s Yangtze River Delta. The results showed that the overall LCEs performed as a rising trend during 2010–2019. The LCEs of the eastern cities and provincial capitals were significantly higher than those of other cities with obvious spatial agglomerations. For driving factors, the gross domestic product, population size, and proportion of tertiary industry all had significant positive influences on the LCEs. Overall, this study is of great practical significance to accurately obtain information on the spatial-temporal dynamics of LCEs at the city-level scale, so as to facilitate the differentiated implementation of carbon reduction measures.
{"title":"Spatial-Temporal Patterns and Driving Factors of Logistics Carbon Emissions: Case Study of Yangtze River Delta in China","authors":"Enyan Zhu, Jian Yao, Wenjia Zheng, Chang Sun, Mei Sha","doi":"10.1177/03611981241242068","DOIUrl":"https://doi.org/10.1177/03611981241242068","url":null,"abstract":"With the growing dependence of human beings on the logistics industry, the trend of logistics carbon emissions (LCEs) growth has become much more serious. To investigate the spatial-temporal pattern of LCEs as well as their driving factors, city-scale LCEs were calculated by combining them with nighttime light remote sensing data. In addition, a spatial panel data model was applied in the case of China’s Yangtze River Delta. The results showed that the overall LCEs performed as a rising trend during 2010–2019. The LCEs of the eastern cities and provincial capitals were significantly higher than those of other cities with obvious spatial agglomerations. For driving factors, the gross domestic product, population size, and proportion of tertiary industry all had significant positive influences on the LCEs. Overall, this study is of great practical significance to accurately obtain information on the spatial-temporal dynamics of LCEs at the city-level scale, so as to facilitate the differentiated implementation of carbon reduction measures.","PeriodicalId":309251,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141104039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：