Pub Date : 2024-10-01DOI: 10.1016/j.jtte.2022.07.007
Lei Jiang , Yongjian Liu , Neil A. Hoult , Xin Long , Wenshuai Wang
Stress concentration factors (SCFs) for welded tubular joints can be decreased by filling the chord with concrete leading to a longer fatigue life. However, there are currently no design formula available in guidelines to predict the SCF of concrete-filled circular hollow section (CFCHS) K-joints, thus limiting their applicability in bridge design. To address this gap, finite element models for CFCHS K-joints were developed and compared against test results to ensure their accuracy. Then, a comprehensive parametric study was conducted to establish relationships between maximum SCFs and four variables: brace-to-chord diameter ratio (β), chord diameter-to-thickness ratio (2γ), brace-to-chord thickness ratio (τ), and the angle between braces and chord (θ). A total of 480 FE models were examined under three loading conditions including brace and chord loading: balanced axial force, chord axial force, and chord bending. Design equations to predict the maximum SCF for CFCHS K-joints were established by multiple regression analyses of the numerical results. A comparison of maximum SCFs between circular hollow section (CHS) and CFCHS K-joints was made, and it was concluded that average reductions of 42% and 33% in maximum SCFs in CFCHS K-joints at the locations of the chord and brace were found compared to CHS joints for balanced axial force, respectively. Finally, a case study illustrating how to use the proposed equations for fatigue safety verification was presented.
通过在弦部填充混凝土可以降低焊接管状接头的应力集中系数（SCF），从而延长疲劳寿命。然而，目前还没有任何设计公式可用于预测混凝土填充圆形空心截面（CFCHS）K 型接头的应力集中系数，因此限制了其在桥梁设计中的应用。为了填补这一空白，我们开发了 CFCHS K 型连接件的有限元模型，并将其与测试结果进行比较，以确保其准确性。然后，进行了全面的参数研究，以确定最大 SCF 与四个变量之间的关系：支撑与弦直径比 (β)、弦直径与厚度比 (2γ)、支撑与弦厚度比 (τ)，以及支撑与弦之间的角度 (θ)。共有 480 个有限元模型在三种加载条件下进行了检验，包括支架和弦杆加载：平衡轴向力、弦杆轴向力和弦杆弯曲。通过对数值结果进行多元回归分析，建立了预测 CFCHS K 型关节最大 SCF 的设计方程。对圆形空心截面（CHS）和 CFCHS K 型接头的最大 SCF 进行了比较，得出的结论是，与 CHS 接头相比，CFCHS K 型接头在平衡轴向力下，弦杆和支撑位置的最大 SCF 平均分别降低了 42% 和 33%。最后，介绍了一个案例研究，说明如何使用所提出的公式进行疲劳安全验证。
{"title":"Design equations for maximum stress concentration factors for concrete-filled steel tubular K-joints","authors":"Lei Jiang , Yongjian Liu , Neil A. Hoult , Xin Long , Wenshuai Wang","doi":"10.1016/j.jtte.2022.07.007","DOIUrl":"10.1016/j.jtte.2022.07.007","url":null,"abstract":"<div><div>Stress concentration factors (SCFs) for welded tubular joints can be decreased by filling the chord with concrete leading to a longer fatigue life. However, there are currently no design formula available in guidelines to predict the SCF of concrete-filled circular hollow section (CFCHS) K-joints, thus limiting their applicability in bridge design. To address this gap, finite element models for CFCHS K-joints were developed and compared against test results to ensure their accuracy. Then, a comprehensive parametric study was conducted to establish relationships between maximum SCFs and four variables: brace-to-chord diameter ratio (<em>β</em>), chord diameter-to-thickness ratio (2<em>γ</em>), brace-to-chord thickness ratio (<em>τ</em>), and the angle between braces and chord (<em>θ</em>). A total of 480 FE models were examined under three loading conditions including brace and chord loading: balanced axial force, chord axial force, and chord bending. Design equations to predict the maximum SCF for CFCHS K-joints were established by multiple regression analyses of the numerical results. A comparison of maximum SCFs between circular hollow section (CHS) and CFCHS K-joints was made, and it was concluded that average reductions of 42% and 33% in maximum SCFs in CFCHS K-joints at the locations of the chord and brace were found compared to CHS joints for balanced axial force, respectively. Finally, a case study illustrating how to use the proposed equations for fatigue safety verification was presented.</div></div>","PeriodicalId":47239,"journal":{"name":"Journal of Traffic and Transportation Engineering-English Edition","volume":"11 5","pages":"Pages 1001-1022"},"PeriodicalIF":7.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.jtte.2024.09.001
Yisong Chen, Xiaofang Dai, Pei Fu, Geng Luo, Peilong Shi
To promote the improvement and development of China's automotive industry policy, this study conducts a systematic review and hierarchical analysis of both domestic and international automotive industry policies. First, the automotive industry policies of the United States, Germany, South Korea, and Japan are summarized in terms of their industrial structure adjustment, technological innovation, taxes and financial subsidies, and infrastructure construction. Benchmarking the policies of international automotive industry powers provides a reference and basis for integrating their experiences in the formulation of China's automotive industry policy. Second, beginning with China's “Automotive Industry Policy” issued in 1994, the key automotive industry policies at different points in history and under different strategies are analyzed. Through policy adjustment and target setting, the changing focus through the historical development of China's automotive industry is determined, along with the development of the industry and technological progress. Then, from the perspectives of strategic planning, promotion and application, credit management, infrastructure, management standards, and standard systems, the advantages and disadvantages of current development policies for new energy and intelligent connected vehicles are clarified. The challenges and limitations of China's automotive industry policy are summarized, including a lack of investment in technology research and development, low level of infrastructure support, and insufficient consumer protection. China's automotive industry policy is then into three different historical stages: i) 1994 to 2008, ii) 2009 to 2013, and iii) 2014 to present; and the characteristics of each stage are summarized. Finally, based on China's national conditions and considering the future development trends of the international automotive industry, the study concludes that under the strong drivers of carbon peak and neutrality goals, China's future automotive industry policy should feature energy saving and emission reduction as the main goals. Independent innovation should be the main enabler, strengthening and supplementing the supply chain through intelligent connectivity.
{"title":"A review of China's automotive industry policy: Recent developments and future trends","authors":"Yisong Chen, Xiaofang Dai, Pei Fu, Geng Luo, Peilong Shi","doi":"10.1016/j.jtte.2024.09.001","DOIUrl":"10.1016/j.jtte.2024.09.001","url":null,"abstract":"<div><div>To promote the improvement and development of China's automotive industry policy, this study conducts a systematic review and hierarchical analysis of both domestic and international automotive industry policies. First, the automotive industry policies of the United States, Germany, South Korea, and Japan are summarized in terms of their industrial structure adjustment, technological innovation, taxes and financial subsidies, and infrastructure construction. Benchmarking the policies of international automotive industry powers provides a reference and basis for integrating their experiences in the formulation of China's automotive industry policy. Second, beginning with China's “Automotive Industry Policy” issued in 1994, the key automotive industry policies at different points in history and under different strategies are analyzed. Through policy adjustment and target setting, the changing focus through the historical development of China's automotive industry is determined, along with the development of the industry and technological progress. Then, from the perspectives of strategic planning, promotion and application, credit management, infrastructure, management standards, and standard systems, the advantages and disadvantages of current development policies for new energy and intelligent connected vehicles are clarified. The challenges and limitations of China's automotive industry policy are summarized, including a lack of investment in technology research and development, low level of infrastructure support, and insufficient consumer protection. China's automotive industry policy is then into three different historical stages: i) 1994 to 2008, ii) 2009 to 2013, and iii) 2014 to present; and the characteristics of each stage are summarized. Finally, based on China's national conditions and considering the future development trends of the international automotive industry, the study concludes that under the strong drivers of carbon peak and neutrality goals, China's future automotive industry policy should feature energy saving and emission reduction as the main goals. Independent innovation should be the main enabler, strengthening and supplementing the supply chain through intelligent connectivity.</div></div>","PeriodicalId":47239,"journal":{"name":"Journal of Traffic and Transportation Engineering-English Edition","volume":"11 5","pages":"Pages 867-895"},"PeriodicalIF":7.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.jtte.2024.04.006
Francesco Canestrari, Eugenio Mariani, Lorenzo Paolo Ingrassia
Pavement skid resistance plays a crucial role in ensuring road safety and avoiding accidents. In the past, the laboratory evaluation of the skid resistance was carried out by studying only the coarse aggregates of the wearing course. To overcome this drawback, the Wehner-Schulze (WS) machine was developed in Germany in the 1960s. This equipment, composed of a polishing unit and a measuring unit, has great potential in predicting pavement skid resistance and its evolution over time, but is still little known in the pavement community (especially outside Europe). For these reasons, there is a need of a comprehensive review of the existing technical-scientific literature concerning the use of the WS machine. Specifically, this paper focuses on the main factors affecting the skid resistance in WS tests, the correlation of WS data with other laboratory test methods and with field skid resistance/polishing, and the available prediction models that have been validated through WS measurements. The critical analysis of the existing literature highlights that it is possible to correlate WS data with typical skid resistance field measurements as well as WS polishing with traffic polishing, but further efforts are needed in this regard. Future work should focus especially on open-graded mixtures and innovative asphalt mixtures (e.g., containing recycled materials and additives). From the perspective of pavement management, based on a theoretical background, the WS test results could be used as starting point for simplified prediction models of the in-situ skid resistance.
{"title":"Use of Wehner-Schulze machine to evaluate pavement skid resistance: A review","authors":"Francesco Canestrari, Eugenio Mariani, Lorenzo Paolo Ingrassia","doi":"10.1016/j.jtte.2024.04.006","DOIUrl":"10.1016/j.jtte.2024.04.006","url":null,"abstract":"<div><div>Pavement skid resistance plays a crucial role in ensuring road safety and avoiding accidents. In the past, the laboratory evaluation of the skid resistance was carried out by studying only the coarse aggregates of the wearing course. To overcome this drawback, the Wehner-Schulze (WS) machine was developed in Germany in the 1960s. This equipment, composed of a polishing unit and a measuring unit, has great potential in predicting pavement skid resistance and its evolution over time, but is still little known in the pavement community (especially outside Europe). For these reasons, there is a need of a comprehensive review of the existing technical-scientific literature concerning the use of the WS machine. Specifically, this paper focuses on the main factors affecting the skid resistance in WS tests, the correlation of WS data with other laboratory test methods and with field skid resistance/polishing, and the available prediction models that have been validated through WS measurements. The critical analysis of the existing literature highlights that it is possible to correlate WS data with typical skid resistance field measurements as well as WS polishing with traffic polishing, but further efforts are needed in this regard. Future work should focus especially on open-graded mixtures and innovative asphalt mixtures (e.g., containing recycled materials and additives). From the perspective of pavement management, based on a theoretical background, the WS test results could be used as starting point for simplified prediction models of the in-situ skid resistance.</div></div>","PeriodicalId":47239,"journal":{"name":"Journal of Traffic and Transportation Engineering-English Edition","volume":"11 5","pages":"Pages 896-917"},"PeriodicalIF":7.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.jtte.2023.12.001
Shahrbanoo Kavianpour , Farshidreza Haghighi , Abbas Sheykhfard , Subasish Das , Grigorios Fountas , Mohammad Mehdi Oshanreh
While pedestrian crashes on suburban roads have received more attention over recent years, the role of pedestrian crossing risk in areas adjacent to pedestrian crossing facilities, such as pedestrian overpasses, has been neglected. Most pedestrians in suburban areas tend to avoid pedestrian overpasses, exhibiting crossing behaviors that increase the likelihood of pedestrian-involving crashes. As a result of the presence of overpasses, drivers may think that there are no pedestrians in the surroundings, so they choose a speed based only on the prevailing traffic and road environment without accounting for potential interactions with pedestrians. Consequently, crashes will occur, with pedestrians typically being the most seriously affected casualties. In this study, using video recordings from a suburban road in Amol-Babol, Iran, the risk of pedestrian crossing behavior in areas near pedestrian overpasses is investigated. The speed selection behavior of drivers in these areas has also been examined using speedometer cameras. To quantify the level of risk for pedestrians when interacting with approaching vehicles during the crossing movements, the post encroachment time (PET) was used as a surrogate safety measure. Based on critical thresholds of PET, three different risk levels were identified using a K-means algorithm: high, medium, and low risk. To identify the elements affecting the risk of pedestrian crossing behavior, structural equation models were estimated for all three risk levels. The results showed that human factors, relating to both drivers and pedestrians, have a dominant impact on pedestrian safety, especially in high and medium risk contexts. Road and vehicle factors were also found to have statistically observable effects on pedestrian safety, but to a milder extent compared to human factors. The findings of this study highlight the need for intervening in several aspects of vehicle-pedestrian interactions with critical importance for pedestrian safety, including road users’ performance and compliance, state of alertness, and interaction with road infrastructure.
近年来，郊区道路上的行人碰撞事故受到越来越多的关注，但行人过街风险在行人过街设施（如人行天桥）附近地区的作用却一直被忽视。郊区的大多数行人都倾向于避开人行过街天桥，他们的过街行为增加了发生行人碰撞事故的可能性。由于立交桥的存在，驾驶员可能会认为周围没有行人，因此只根据当时的交通和道路环境选择车速，而不考虑可能与行人发生的相互作用。因此，碰撞事故就会发生，而行人通常是受影响最严重的伤亡者。本研究利用伊朗阿莫尔-巴波尔郊区道路的视频记录，调查了行人过街行为在人行天桥附近区域的风险。此外，还使用测速照相机对这些地区驾驶员的速度选择行为进行了研究。为了量化行人在横穿马路时与驶来车辆相互作用的风险水平，使用了侵占后时间（PET）作为替代安全措施。根据 PET 的临界阈值，使用 K-means 算法确定了三种不同的风险等级：高风险、中风险和低风险。为了确定影响行人过马路行为风险的因素，对所有三个风险等级进行了结构方程模型估算。结果表明，与驾驶员和行人有关的人为因素对行人安全有主要影响，尤其是在高风险和中风险情况下。从统计学角度看，道路和车辆因素对行人安全也有影响，但与人为因素相比，影响程度较轻。这项研究的结果突出表明，有必要对车辆与行人互动中对行人安全至关重要的几个方面进行干预，包括道路使用者的表现和遵守情况、警觉状态以及与道路基础设施的互动。
{"title":"Assessing the risk of pedestrian crossing behavior on suburban roads using structural equation model","authors":"Shahrbanoo Kavianpour , Farshidreza Haghighi , Abbas Sheykhfard , Subasish Das , Grigorios Fountas , Mohammad Mehdi Oshanreh","doi":"10.1016/j.jtte.2023.12.001","DOIUrl":"10.1016/j.jtte.2023.12.001","url":null,"abstract":"<div><div>While pedestrian crashes on suburban roads have received more attention over recent years, the role of pedestrian crossing risk in areas adjacent to pedestrian crossing facilities, such as pedestrian overpasses, has been neglected. Most pedestrians in suburban areas tend to avoid pedestrian overpasses, exhibiting crossing behaviors that increase the likelihood of pedestrian-involving crashes. As a result of the presence of overpasses, drivers may think that there are no pedestrians in the surroundings, so they choose a speed based only on the prevailing traffic and road environment without accounting for potential interactions with pedestrians. Consequently, crashes will occur, with pedestrians typically being the most seriously affected casualties. In this study, using video recordings from a suburban road in Amol-Babol, Iran, the risk of pedestrian crossing behavior in areas near pedestrian overpasses is investigated. The speed selection behavior of drivers in these areas has also been examined using speedometer cameras. To quantify the level of risk for pedestrians when interacting with approaching vehicles during the crossing movements, the post encroachment time (PET) was used as a surrogate safety measure. Based on critical thresholds of PET, three different risk levels were identified using a <em>K</em>-means algorithm: high, medium, and low risk. To identify the elements affecting the risk of pedestrian crossing behavior, structural equation models were estimated for all three risk levels. The results showed that human factors, relating to both drivers and pedestrians, have a dominant impact on pedestrian safety, especially in high and medium risk contexts. Road and vehicle factors were also found to have statistically observable effects on pedestrian safety, but to a milder extent compared to human factors. The findings of this study highlight the need for intervening in several aspects of vehicle-pedestrian interactions with critical importance for pedestrian safety, including road users’ performance and compliance, state of alertness, and interaction with road infrastructure.</div></div>","PeriodicalId":47239,"journal":{"name":"Journal of Traffic and Transportation Engineering-English Edition","volume":"11 5","pages":"Pages 853-866"},"PeriodicalIF":7.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.jtte.2023.07.011
Peiliang Cong, Ruyan Du, Huanlin Gao, Zhihui Chen
Geopolymer concrete (GPC) has been developed as a sustainable alternative to traditional cement-based concrete using industrial waste materials. Thus, reducing greenhouse gas emissions in concrete production can be expected. This study employed the life cycle assessment (LCA) method to evaluate geopolymer concrete's cost and life-cycle carbon dioxide (CO2) emissions. Moreover, the critical transportation radius of the geopolymer is estimated. Then, evaluation results were compared with ordinary Portland cement (OPC), considering three concrete construction methods: cast-in-place, ready-mixed, and precast. In particular, the service life of two types of concrete in sulfuric acid environments is considered. Compared with OPC concrete, the results show that geopolymer concretes can significantly reduce the cost and CO2 emissions when one or a small amount of alkali activator is used or alkali-containing materials are used to replace some alkali activators. However, the advantages would be reversed by the rising alkali dosages, which account for cost increases and carbon emissions. When considering the service life in special environments, geopolymer concrete in sulfuric acid environments corresponds to fewer carbon emissions, 94%–97% decreased compared with OPC concrete. Finally, compared with OPC concrete, the newly developed limestone calcined clay cement (LC3) avoids high-temperature calcination and dramatically reduces carbon dioxide emissions. Compared to OPC concrete, LC3 concrete has a 19% reduction in CO2 emissions. And geopolymer concrete that takes alkali-activate materials for superseding alkalis also produces less carbon dioxide emissions. In particular, CO2 emissions from FA-SF geopolymer concrete are approximately 50% lower than OPC concrete. In addition, the use of alkali activators significantly weakens the cost advantage of geopolymers. But after accounting for waste disposal costs, the average net cost of fly ash-based geopolymer concrete can be more than 30% lower than that of OPC concrete. The average net cost of slag-based geopolymer concrete is 7%–45% lower than that of OPC concrete. The findings of this work provide the basis for further development of geopolymer concretes obeyed environmental protection.
{"title":"Comparison and assessment of carbon dioxide emissions between alkali-activated materials and OPC cement concrete","authors":"Peiliang Cong, Ruyan Du, Huanlin Gao, Zhihui Chen","doi":"10.1016/j.jtte.2023.07.011","DOIUrl":"10.1016/j.jtte.2023.07.011","url":null,"abstract":"<div><div>Geopolymer concrete (GPC) has been developed as a sustainable alternative to traditional cement-based concrete using industrial waste materials. Thus, reducing greenhouse gas emissions in concrete production can be expected. This study employed the life cycle assessment (LCA) method to evaluate geopolymer concrete's cost and life-cycle carbon dioxide (CO<sub>2</sub>) emissions. Moreover, the critical transportation radius of the geopolymer is estimated. Then, evaluation results were compared with ordinary Portland cement (OPC), considering three concrete construction methods: cast-in-place, ready-mixed, and precast. In particular, the service life of two types of concrete in sulfuric acid environments is considered. Compared with OPC concrete, the results show that geopolymer concretes can significantly reduce the cost and CO<sub>2</sub> emissions when one or a small amount of alkali activator is used or alkali-containing materials are used to replace some alkali activators. However, the advantages would be reversed by the rising alkali dosages, which account for cost increases and carbon emissions. When considering the service life in special environments, geopolymer concrete in sulfuric acid environments corresponds to fewer carbon emissions, 94%–97% decreased compared with OPC concrete. Finally, compared with OPC concrete, the newly developed limestone calcined clay cement (LC3) avoids high-temperature calcination and dramatically reduces carbon dioxide emissions. Compared to OPC concrete, LC3 concrete has a 19% reduction in CO<sub>2</sub> emissions. And geopolymer concrete that takes alkali-activate materials for superseding alkalis also produces less carbon dioxide emissions. In particular, CO<sub>2</sub> emissions from FA-SF geopolymer concrete are approximately 50% lower than OPC concrete. In addition, the use of alkali activators significantly weakens the cost advantage of geopolymers. But after accounting for waste disposal costs, the average net cost of fly ash-based geopolymer concrete can be more than 30% lower than that of OPC concrete. The average net cost of slag-based geopolymer concrete is 7%–45% lower than that of OPC concrete. The findings of this work provide the basis for further development of geopolymer concretes obeyed environmental protection.</div></div>","PeriodicalId":47239,"journal":{"name":"Journal of Traffic and Transportation Engineering-English Edition","volume":"11 5","pages":"Pages 918-938"},"PeriodicalIF":7.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1016/j.jtte.2022.12.003
Ning Wang , Hangqi Tian , Jiahui Guo , Huahua Wu , Jian Lyu
Long waiting delays for users and significant imbalances in vehicle distribution are bothering traditional station-based one-way electric car-sharing system operators. To address the problems above, a “demand forecast-station status judgement-vehicle relocation” multistage dynamic relocation algorithm based on the automatic formation cruising technology was proposed in this study. In stage one, a novel trip demand forecast model based on the long short-term memory network was established to predict users' car-pickup and car-return order volumes at each station. In stage two, a dynamic threshold interval was determined by combining the forecast results with the actual vehicle distribution among stations to evaluate the status of each station. Then vehicle-surplus, vehicle-insufficient, vehicle-normal stations, and the number of surplus or insufficient vehicles for each station were counted. In stage three, setting driving mileage and carbon emission as the optimization objectives, an integer linear programming mathematical model was constructed and the optimal vehicle relocation scheme was obtained by the commercial solver Gurobi. Setting 43 stations and 187 vehicles in Jiading District, Shanghai, China, as a case study, results showed that rapid vehicle rebalancing among stations with minimum carbon emissions could be realized within 15 min and the users’ car-pickup and car-return demands could be fully satisfied without any refusal.
{"title":"Efficiency-oriented vehicle relocation of shared autonomous electric fleet in station-based car-sharing system","authors":"Ning Wang , Hangqi Tian , Jiahui Guo , Huahua Wu , Jian Lyu","doi":"10.1016/j.jtte.2022.12.003","DOIUrl":"10.1016/j.jtte.2022.12.003","url":null,"abstract":"<div><p>Long waiting delays for users and significant imbalances in vehicle distribution are bothering traditional station-based one-way electric car-sharing system operators. To address the problems above, a “demand forecast-station status judgement-vehicle relocation” multistage dynamic relocation algorithm based on the automatic formation cruising technology was proposed in this study. In stage one, a novel trip demand forecast model based on the long short-term memory network was established to predict users' car-pickup and car-return order volumes at each station. In stage two, a dynamic threshold interval was determined by combining the forecast results with the actual vehicle distribution among stations to evaluate the status of each station. Then vehicle-surplus, vehicle-insufficient, vehicle-normal stations, and the number of surplus or insufficient vehicles for each station were counted. In stage three, setting driving mileage and carbon emission as the optimization objectives, an integer linear programming mathematical model was constructed and the optimal vehicle relocation scheme was obtained by the commercial solver Gurobi. Setting 43 stations and 187 vehicles in Jiading District, Shanghai, China, as a case study, results showed that rapid vehicle rebalancing among stations with minimum carbon emissions could be realized within 15 min and the users’ car-pickup and car-return demands could be fully satisfied without any refusal.</p></div>","PeriodicalId":47239,"journal":{"name":"Journal of Traffic and Transportation Engineering-English Edition","volume":"11 4","pages":"Pages 681-699"},"PeriodicalIF":7.4,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2095756424000758/pdfft?md5=7f5a2b9bf77fabfe5a9982ead8e12ab2&pid=1-s2.0-S2095756424000758-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142097268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1016/j.jtte.2024.06.001
Wei Lin , Heng Wei , Lan Yang , Xiangmo Zhao
A massive market penetration of electric vehicles (EVs) associated with nonnegligible energy consumption and environmental issues has imposed a big challenge on evaluating electrical power distribution and related transportation facilities improvement in response to the large-scale EV charging service need. Strategical deployment of EV charging stations including location and determination of number of slow charging stations and fast charging stations has become an emerging concern and one of the most pressing needs in planning. This paper conducts a comprehensive survey of EV charging demand and distribution models with consideration of realistic driver behaviors impacts. This is currently a shortage in academic literature, but indeed has drawn practical attention in the strategic planning process. To address the need, this paper presents an in-depth literature review of relevant studies that have identified different types of EV charging facilities, needs or concerns that are considered into EV charging demand and distribution modeling, alongside critical impacting factor identification, mathematical relationships of the contributing factors and EV charging demand and distribution modeling. Key findings from the current literature are summarized with strategies for optimized plan of charging station deployments (i.e., location and related number of charging station), in an attempt to provide a valuable reference for interested readers.
{"title":"Technical review of electric vehicle charging distribution models with considering driver behaviors impacts","authors":"Wei Lin , Heng Wei , Lan Yang , Xiangmo Zhao","doi":"10.1016/j.jtte.2024.06.001","DOIUrl":"10.1016/j.jtte.2024.06.001","url":null,"abstract":"<div><p>A massive market penetration of electric vehicles (EVs) associated with nonnegligible energy consumption and environmental issues has imposed a big challenge on evaluating electrical power distribution and related transportation facilities improvement in response to the large-scale EV charging service need. Strategical deployment of EV charging stations including location and determination of number of slow charging stations and fast charging stations has become an emerging concern and one of the most pressing needs in planning. This paper conducts a comprehensive survey of EV charging demand and distribution models with consideration of realistic driver behaviors impacts. This is currently a shortage in academic literature, but indeed has drawn practical attention in the strategic planning process. To address the need, this paper presents an in-depth literature review of relevant studies that have identified different types of EV charging facilities, needs or concerns that are considered into EV charging demand and distribution modeling, alongside critical impacting factor identification, mathematical relationships of the contributing factors and EV charging demand and distribution modeling. Key findings from the current literature are summarized with strategies for optimized plan of charging station deployments (i.e., location and related number of charging station), in an attempt to provide a valuable reference for interested readers.</p></div>","PeriodicalId":47239,"journal":{"name":"Journal of Traffic and Transportation Engineering-English Edition","volume":"11 4","pages":"Pages 643-666"},"PeriodicalIF":7.4,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2095756424000692/pdfft?md5=5c75e8b7ae64e605fdcedd5189413373&pid=1-s2.0-S2095756424000692-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141839611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Load limits, which appear to be routinely exceeded by trucks, occasionally result in road bridge failures. Therefore, predicting failures is crucial for safeguarding road safety. Past studies have largely focused on forecasting bridge failure event probability using the reliability analysis method, whilst occasionally accounting for vehicular overloading effects. Only recently, a study has investigated design traffic overloading event frequency using generalised linear regression models (GLRMs), including a power component and negative binomial regressions (NBRs). However, as far as the authors know, artificial neural network models (ANNMs) have never been applied to this field. This paper is an attempt to fill in these gaps. First a frequency-based metric of traffic overloading was adopted as a driver of failure probability. Second, two alternative ‘frequency’ models were specified, calibrated, and validated. The former was based on a GLRM, the latter on ANNMs. Then, these models were compared using regression plots (RPs), measures of errors (MoEs) and the ratio between the number of observed vs predicted design load overcoming events to evaluate their performance. The models analysed more than 2 million weigh-in-motion (WIM) data records from a pilot station on a bridge on a heavily used ring road in Brescia (Italy). Results showed that ANNMs outperformed GLRMs. ANNMs have a higher correlation coefficient (between predicted and target frequencies), lower MoEs, and a closer-to-unity ratio (between predicted and target frequencies). These findings may increase prediction accuracy of design traffic overloading events and give road authorities more effective traffic management to protect bridges from load hazards.
{"title":"Estimating the frequency of traffic overloading on road bridges","authors":"Roberto Ventura, Benedetto Barabino, Giulio Maternini","doi":"10.1016/j.jtte.2023.11.005","DOIUrl":"10.1016/j.jtte.2023.11.005","url":null,"abstract":"<div><p>Load limits, which appear to be routinely exceeded by trucks, occasionally result in road bridge failures. Therefore, predicting failures is crucial for safeguarding road safety. Past studies have largely focused on forecasting bridge failure event probability using the reliability analysis method, whilst occasionally accounting for vehicular overloading effects. Only recently, a study has investigated design traffic overloading event frequency using generalised linear regression models (GLRMs), including a power component and negative binomial regressions (NBRs). However, as far as the authors know, artificial neural network models (ANNMs) have never been applied to this field. This paper is an attempt to fill in these gaps. First a frequency-based metric of traffic overloading was adopted as a driver of failure probability. Second, two alternative ‘frequency’ models were specified, calibrated, and validated. The former was based on a GLRM, the latter on ANNMs. Then, these models were compared using regression plots (RPs), measures of errors (MoEs) and the ratio between the number of observed vs predicted design load overcoming events to evaluate their performance. The models analysed more than 2 million weigh-in-motion (WIM) data records from a pilot station on a bridge on a heavily used ring road in Brescia (Italy). Results showed that ANNMs outperformed GLRMs. ANNMs have a higher correlation coefficient (between predicted and target frequencies), lower MoEs, and a closer-to-unity ratio (between predicted and target frequencies). These findings may increase prediction accuracy of design traffic overloading events and give road authorities more effective traffic management to protect bridges from load hazards.</p></div>","PeriodicalId":47239,"journal":{"name":"Journal of Traffic and Transportation Engineering-English Edition","volume":"11 4","pages":"Pages 776-796"},"PeriodicalIF":7.4,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S209575642400076X/pdfft?md5=d625b650b0ad196b4b22d06ec1d53a9c&pid=1-s2.0-S209575642400076X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142098025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1016/j.jtte.2023.05.010
Anna Niska , Leif Sjögren , Peter Andrén , Christian Weber , Tineke de Jong , Aslak Fyhri
Well maintained cycleways will encourage more people to cycle, as the condition of cycleways is important for the safety, accessibility and riding comfort of cyclists. Despite that, only a few models used to describe the quality of service for cyclists take the surface condition into account. Objective measuring methods are needed to enable reliable and effective assessment of surface conditions, and measurable performance criteria related to the needs of cyclists should be developed. The purpose of this study has been to test the reliability and validity of using accelerometers in smartphones to assess the riding comfort on cycleways. A smartphone application converting three-dimensional accelerometer measurements into a single indicator for cycleways has been used to assess road surfaces in two field studies, in Sweden and Norway, respectively. Both studies assessed test sections of varying quality. To relate the measurements to subjective riding comfort assessments by cyclists, recruited cyclists collected quantitative data using the app, whilst also rating their perceived riding comfort by completing a survey. Measurements were also related to standard road surface condition indicators, generated from a road surface tester equipped with 19 laser sensors: international roughness index (IRI), mega- and macrotexture. The results show that it is possible to describe the unevenness of a cycleway using the technology present in smartphones. A software application can be used to collect and analyse data from the acceleration sensors in the phone, which can then be used to describe the riding comfort of cyclists. It is mainly the unevenness in the 50–1000 mm size-range that create the greatest discomfort for cyclists, and intermittent vibrations are perceived as more uncomfortable than more evenly distributed vibrations. Therefore, IRI is not a relevant measurement for describing the riding comfort of cyclists.
{"title":"Determination of riding comfort on cycleways using a smartphone application","authors":"Anna Niska , Leif Sjögren , Peter Andrén , Christian Weber , Tineke de Jong , Aslak Fyhri","doi":"10.1016/j.jtte.2023.05.010","DOIUrl":"10.1016/j.jtte.2023.05.010","url":null,"abstract":"<div><p>Well maintained cycleways will encourage more people to cycle, as the condition of cycleways is important for the safety, accessibility and riding comfort of cyclists. Despite that, only a few models used to describe the quality of service for cyclists take the surface condition into account. Objective measuring methods are needed to enable reliable and effective assessment of surface conditions, and measurable performance criteria related to the needs of cyclists should be developed. The purpose of this study has been to test the reliability and validity of using accelerometers in smartphones to assess the riding comfort on cycleways. A smartphone application converting three-dimensional accelerometer measurements into a single indicator for cycleways has been used to assess road surfaces in two field studies, in Sweden and Norway, respectively. Both studies assessed test sections of varying quality. To relate the measurements to subjective riding comfort assessments by cyclists, recruited cyclists collected quantitative data using the app, whilst also rating their perceived riding comfort by completing a survey. Measurements were also related to standard road surface condition indicators, generated from a road surface tester equipped with 19 laser sensors: international roughness index (IRI), mega- and macrotexture. The results show that it is possible to describe the unevenness of a cycleway using the technology present in smartphones. A software application can be used to collect and analyse data from the acceleration sensors in the phone, which can then be used to describe the riding comfort of cyclists. It is mainly the unevenness in the 50–1000 mm size-range that create the greatest discomfort for cyclists, and intermittent vibrations are perceived as more uncomfortable than more evenly distributed vibrations. Therefore, IRI is not a relevant measurement for describing the riding comfort of cyclists.</p></div>","PeriodicalId":47239,"journal":{"name":"Journal of Traffic and Transportation Engineering-English Edition","volume":"11 4","pages":"Pages 747-760"},"PeriodicalIF":7.4,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2095756424000771/pdfft?md5=cec002baf20a7d28fb3f5f964fb5ce32&pid=1-s2.0-S2095756424000771-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142098022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fluid flow throttling is common in industrial and building services engineering. Similar tunnel throttling of vehicular flow is caused by the abrupt number reduction of roadway lane, as the tunnel has a lower lane number than in the roadway normal segment. To predict the effects of tunnel throttling of annular freeway vehicular flow, a three-lane continuum model is developed. Lane III of the tunnel is completely blocked due to the need of tunnel rehabilitation, etc. There exists mandatory net lane-changing rate from lane III to lane II just upstream of the tunnel entrance, which is described by a model of random number generated through a golden section analysis. The net-changing rate between adjacent lanes is modeled using a lane-changing time expressed explicitly in algebraic form. This paper assumes that the annular freeway has a total length of 100 km, a two-lane tunnel of length 2 km with a speed limit of 80 km/h. The free flow speeds on lanes I, II and III are assumed to be 110, 100 and 90 km/h respectively. Based on the three-lane continuum model, numerical simulations of vehicular flows on the annular freeway with such a tunnel are conducted with a reliable numerical method of 3rd-order accuracy. Numerical results reveal that the vehicular flow has a smaller threshold of traffic jam formation in comparison with the case without tunnel throttling. Vehicle fuel consumption can be estimated by interpolation with time averaged grid traffic speed and an assumed curve of vehicle performance. The vehicle fuel consumption is lane number dependent, distributes with initial density concavely, ranging from 5.56 to 8.00 L. Tunnel throttling leads to an earlier traffic jam formation in comparison with the case without tunnel throttling.
流体节流在工业和建筑服务工程中很常见。类似的隧道车流节流是由路面车道数突然减少引起的，因为隧道的车道数比路面正常路段的车道数要少。为了预测隧道节流对环形高速公路车流的影响，我们建立了一个三车道连续模型。由于隧道修复等原因，隧道 III 车道完全阻塞。在隧道入口上游存在从车道 III 到车道 II 的强制性净变线率，通过黄金分割分析生成的随机数模型对其进行描述。相邻车道之间的净变道率使用以代数形式明确表示的变道时间来建模。本文假设环形高速公路总长 100 公里，双线隧道长 2 公里，限速 80 公里/小时。车道 I、II 和 III 的自由流速度分别假设为 110、100 和 90 km/h。在三车道连续模型的基础上，采用可靠的三阶精度数值方法，对带有这种隧道的环形高速公路上的车辆流进行了数值模拟。数值结果表明，与没有隧道节流的情况相比，车流形成交通堵塞的临界值较小。车辆油耗可通过时间平均网格交通速度和假定的车辆性能曲线进行内插法估算。车辆耗油量与车道数有关，随初始密度呈凹形分布，范围在 5.56 至 8.00 升之间。与不采用隧道节流的情况相比，隧道节流会导致交通堵塞提前形成。
{"title":"Predicting effects of tunnel throttling of annular freeway vehicular flow by a continuum model","authors":"Zhongmin Huang , M.N. Smirnova , N.N. Smirnov , Zuojin Zhu","doi":"10.1016/j.jtte.2022.08.005","DOIUrl":"10.1016/j.jtte.2022.08.005","url":null,"abstract":"<div><p>Fluid flow throttling is common in industrial and building services engineering. Similar tunnel throttling of vehicular flow is caused by the abrupt number reduction of roadway lane, as the tunnel has a lower lane number than in the roadway normal segment. To predict the effects of tunnel throttling of annular freeway vehicular flow, a three-lane continuum model is developed. Lane III of the tunnel is completely blocked due to the need of tunnel rehabilitation, etc. There exists mandatory net lane-changing rate from lane III to lane II just upstream of the tunnel entrance, which is described by a model of random number generated through a golden section analysis. The net-changing rate between adjacent lanes is modeled using a lane-changing time expressed explicitly in algebraic form. This paper assumes that the annular freeway has a total length of 100 km, a two-lane tunnel of length 2 km with a speed limit of 80 km/h. The free flow speeds on lanes I, II and III are assumed to be 110, 100 and 90 km/h respectively. Based on the three-lane continuum model, numerical simulations of vehicular flows on the annular freeway with such a tunnel are conducted with a reliable numerical method of 3rd-order accuracy. Numerical results reveal that the vehicular flow has a smaller threshold of traffic jam formation in comparison with the case without tunnel throttling. Vehicle fuel consumption can be estimated by interpolation with time averaged grid traffic speed and an assumed curve of vehicle performance. The vehicle fuel consumption is lane number dependent, distributes with initial density concavely, ranging from 5.56 to 8.00 L. Tunnel throttling leads to an earlier traffic jam formation in comparison with the case without tunnel throttling.</p></div>","PeriodicalId":47239,"journal":{"name":"Journal of Traffic and Transportation Engineering-English Edition","volume":"11 4","pages":"Pages 733-746"},"PeriodicalIF":7.4,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2095756424000746/pdfft?md5=a93c33d74e8cc23f5c36cb3d69ace95f&pid=1-s2.0-S2095756424000746-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142098026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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