Despite its primary role in shaping policy and service characteristics, board governance is an understudied topic in the field of urban transit. Existing research on board management and representative bureaucracy theory suggests that the race and gender diversity of boards has a significant impact on organizational activity but that these relationships are highly dependent on the cultural context and industry analyzed. In this paper, we evaluate how the diversity of transit boards (with respect to race, gender, and disability) in the U.S.A. correlates with service changes authorized by these boards during the COVID-19 pandemic. Utilizing a database on board governance and general transit feed specification data for 36 agencies, we find a positive relationship between the presence of women on transit boards and vertically equitable service cuts, defined as increasing or maintaining transit service in more vulnerable neighborhoods. Overall, transit agencies with more female board members had more equitable service cuts, on average, during the COVID-19 pandemic.
{"title":"Transit Board Diversity and Pandemic Service Cuts in Vulnerable Communities","authors":"Carole Turley Voulgaris, Rosalie Singerman Ray, Lauren Ames Fischer","doi":"10.1177/03611981241263346","DOIUrl":"https://doi.org/10.1177/03611981241263346","url":null,"abstract":"Despite its primary role in shaping policy and service characteristics, board governance is an understudied topic in the field of urban transit. Existing research on board management and representative bureaucracy theory suggests that the race and gender diversity of boards has a significant impact on organizational activity but that these relationships are highly dependent on the cultural context and industry analyzed. In this paper, we evaluate how the diversity of transit boards (with respect to race, gender, and disability) in the U.S.A. correlates with service changes authorized by these boards during the COVID-19 pandemic. Utilizing a database on board governance and general transit feed specification data for 36 agencies, we find a positive relationship between the presence of women on transit boards and vertically equitable service cuts, defined as increasing or maintaining transit service in more vulnerable neighborhoods. Overall, transit agencies with more female board members had more equitable service cuts, on average, during the COVID-19 pandemic.","PeriodicalId":517391,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867502","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 : 2024-07-30DOI: 10.1177/03611981241262308
Jodi Godfrey, Lisa Staes
As the frontline eyes on communities, transit operators are uniquely positioned to recognize suspicious activities and report them to authorities. Training is necessary to inform and empower transit agencies in the fight against human trafficking. Human trafficking is modern day slavery, which the U.S. Department of Justice defines as a crime that involves the exploitation of a person for labor, services, or commercial sex. Human trafficking is a worldwide criminal industry that the denies freedom of 25 million people around the world. This heinous crime often targets the most vulnerable populations and preys on their needs, weaknesses, and insecurities as a strategy to control their victims through force, fraud, and coercion. This paper reviews the resources available for transit agencies to train their employees on the signs of human trafficking that they should be on the lookout for. Truckers Against Trafficking’s Busing on the Lookout program has shared success stories related to transit employees recognizing situations and saving human trafficking victims. However, the existence of transit agency policies and associated procedures is a recognized resource gap in the transit industry. The available training materials direct trainees to refer to their agency policy on how to report suspicious activity. However, as noted, many transit agencies do not have a formalized policy or procedures in place to dictate how to report suspected human trafficking activity. This paper provides agencies with valuable human trafficking awareness training resources and a response procedure template as tools to improve the awareness and reporting procedures in their agency.
{"title":"Human Trafficking Awareness Training and Response Procedure Template for Transit Agencies","authors":"Jodi Godfrey, Lisa Staes","doi":"10.1177/03611981241262308","DOIUrl":"https://doi.org/10.1177/03611981241262308","url":null,"abstract":"As the frontline eyes on communities, transit operators are uniquely positioned to recognize suspicious activities and report them to authorities. Training is necessary to inform and empower transit agencies in the fight against human trafficking. Human trafficking is modern day slavery, which the U.S. Department of Justice defines as a crime that involves the exploitation of a person for labor, services, or commercial sex. Human trafficking is a worldwide criminal industry that the denies freedom of 25 million people around the world. This heinous crime often targets the most vulnerable populations and preys on their needs, weaknesses, and insecurities as a strategy to control their victims through force, fraud, and coercion. This paper reviews the resources available for transit agencies to train their employees on the signs of human trafficking that they should be on the lookout for. Truckers Against Trafficking’s Busing on the Lookout program has shared success stories related to transit employees recognizing situations and saving human trafficking victims. However, the existence of transit agency policies and associated procedures is a recognized resource gap in the transit industry. The available training materials direct trainees to refer to their agency policy on how to report suspicious activity. However, as noted, many transit agencies do not have a formalized policy or procedures in place to dictate how to report suspected human trafficking activity. This paper provides agencies with valuable human trafficking awareness training resources and a response procedure template as tools to improve the awareness and reporting procedures in their agency.","PeriodicalId":517391,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867505","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 : 2024-07-30DOI: 10.1177/03611981241255368
Zhe Wan, Hao Wang
Airfield pavement marking plays a critical role in the efficient and safe operation of airport. Glass beads are embedded in the paints to refract and reflect light and enhance brightness and contrast for improving the visibility of markings. This study aims to investigate service life and cost-effectiveness of airfield pavement markings using Type I and Type III glass beads based on measured retroreflectivity data. The study employs a three-step approach: descriptive statistical analysis, survival analysis of service life, and life-cycle cost analysis (LCCA). The results show that the painting material is the most influential factor affecting marking performance, followed by the type of glass bead. Among markings with Type I glass beads, those using waterborne Type III and waterborne Type II painting materials show substantial survival time, followed by structural methyl methacrylate (SMMA), while methyl methacrylate (MMA) and waterborne Type I show shortest survival time. For markings with Type III glass beads, SMMA shows the longest lifetime, followed by waterborne Type III, MMA waterborne Type II, and waterborne Type I. With respect to LCCA, waterborne Type III and SMMA with Type III glass beads is found to be the most cost-effective option, while waterborne Type I and MMA with Type I glass beads is identified as the least cost-effective choice.
机场路面标识对机场的高效安全运行起着至关重要的作用。在涂料中嵌入玻璃微珠可以折射和反射光线，增强亮度和对比度，从而提高标识的可见度。本研究旨在根据测量到的逆反射率数据，调查使用 I 类和 III 类玻璃微珠的机场路面标记的使用寿命和成本效益。研究采用了三步方法：描述性统计分析、使用寿命生存分析和生命周期成本分析（LCCA）。结果表明，喷涂材料是影响标识性能的最大因素，其次是玻璃珠的类型。在使用 I 型玻璃珠的标记中，使用水性 III 型和水性 II 型喷涂材料的标记存活时间较长，其次是甲基丙烯酸甲酯（SMMA），而甲基丙烯酸甲酯（MMA）和水性 I 型标记的存活时间最短。就 LCCA 而言，使用 III 型玻璃珠的水性 III 型和 SMMA 是最具成本效益的选择，而使用 I 型玻璃珠的水性 I 型和 MMA 则是成本效益最低的选择。
{"title":"Retroreflectivity-Based Service Life and Life-Cycle Cost Analysis of Airfield Pavement Markings","authors":"Zhe Wan, Hao Wang","doi":"10.1177/03611981241255368","DOIUrl":"https://doi.org/10.1177/03611981241255368","url":null,"abstract":"Airfield pavement marking plays a critical role in the efficient and safe operation of airport. Glass beads are embedded in the paints to refract and reflect light and enhance brightness and contrast for improving the visibility of markings. This study aims to investigate service life and cost-effectiveness of airfield pavement markings using Type I and Type III glass beads based on measured retroreflectivity data. The study employs a three-step approach: descriptive statistical analysis, survival analysis of service life, and life-cycle cost analysis (LCCA). The results show that the painting material is the most influential factor affecting marking performance, followed by the type of glass bead. Among markings with Type I glass beads, those using waterborne Type III and waterborne Type II painting materials show substantial survival time, followed by structural methyl methacrylate (SMMA), while methyl methacrylate (MMA) and waterborne Type I show shortest survival time. For markings with Type III glass beads, SMMA shows the longest lifetime, followed by waterborne Type III, MMA waterborne Type II, and waterborne Type I. With respect to LCCA, waterborne Type III and SMMA with Type III glass beads is found to be the most cost-effective option, while waterborne Type I and MMA with Type I glass beads is identified as the least cost-effective choice.","PeriodicalId":517391,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":"43 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867499","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 : 2024-07-30DOI: 10.1177/03611981241255020
Samuel S. Polzin, Megan Willis-Jackson, Phil White, Karl Meakin, Martha Koch
As the COVID-19 pandemic emerged from the acute phase and vaccines became widely available in 2021, transit agencies like the Massachusetts Bay Transportation Authority (MBTA) faced a daunting challenge of drawing riders back into their systems. Despite systemwide staffing shortages, service disruptions, and ridership patterns that have yet to return to 2019 levels, ridership on MBTA’s Commuter Rail has consistently outperformed the agency’s other services in the current COVID recovery era. In April 2021, as part of a multiyear vision to overhaul the system, MBTA switched from a schedule focused on serving traditional peak-period commuters to providing steady, all-day service modeled on more legible “clockface” departures. This study used regression analysis to show this change was consistent with the Commuter Rail outperforming other modes in ridership recovery, generating over 7,000 average daily weekday boardings and over 9,000 average weekend boardings. Latent class analysis demonstrated that this schedule shift primarily benefited riders traveling for a variety of purposes, rather than just traditional office work. This group, which we referred to as general riders, was more likely to be low-income (household income below $75,000), young (25 or younger), and Hispanic. This research demonstrated the ability of all-day service on Commuter Rail to serve MBTA’s key aims of increasing ridership and providing more equitable, accessible service.
{"title":"A Case Study of Ridership and Equity Implications of All-Day Massachusetts Bay Transportation Authority Commuter Rail Service","authors":"Samuel S. Polzin, Megan Willis-Jackson, Phil White, Karl Meakin, Martha Koch","doi":"10.1177/03611981241255020","DOIUrl":"https://doi.org/10.1177/03611981241255020","url":null,"abstract":"As the COVID-19 pandemic emerged from the acute phase and vaccines became widely available in 2021, transit agencies like the Massachusetts Bay Transportation Authority (MBTA) faced a daunting challenge of drawing riders back into their systems. Despite systemwide staffing shortages, service disruptions, and ridership patterns that have yet to return to 2019 levels, ridership on MBTA’s Commuter Rail has consistently outperformed the agency’s other services in the current COVID recovery era. In April 2021, as part of a multiyear vision to overhaul the system, MBTA switched from a schedule focused on serving traditional peak-period commuters to providing steady, all-day service modeled on more legible “clockface” departures. This study used regression analysis to show this change was consistent with the Commuter Rail outperforming other modes in ridership recovery, generating over 7,000 average daily weekday boardings and over 9,000 average weekend boardings. Latent class analysis demonstrated that this schedule shift primarily benefited riders traveling for a variety of purposes, rather than just traditional office work. This group, which we referred to as general riders, was more likely to be low-income (household income below $75,000), young (25 or younger), and Hispanic. This research demonstrated the ability of all-day service on Commuter Rail to serve MBTA’s key aims of increasing ridership and providing more equitable, accessible service.","PeriodicalId":517391,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867498","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 : 2024-07-30DOI: 10.1177/03611981241262306
Johnny Esteban, Rick Grahn, Bonnie Powell, Stanley E. Young
Legacy fixed-route transit systems designed to serve commuters struggle to provide efficient and effective service for short neighborhood trips and for population groups unable to access and egress transit stops using active modes (e.g., elderly, disabled). Neighborhood on-demand transit (ODT) services using low-speed electric vehicles (LSEVs) are an innovative technological solution that could help fill this gap in service (e.g., short, high-frequency trips) for diverse populations and trip types. This study evaluated user characteristics and travel behavior for a neighborhood ODT service (using LSEVs) in downtown St. Louis, MO, using responses from a community survey ( n = 244), ridership data, and vehicle trajectory information. A comparative analysis between neighborhood ODT, fixed-route transit, and transportation network companies (TNCs) was also conducted from the perspectives of total travel time, cost, and greenhouse gas emissions. Ultimately, the goal of the analysis was to motivate and inform holistic public mobility systems where different services are optimized to meet specific community needs. Findings indicate that the neighborhood ODT was effective at reaching diverse populations (elderly [20%], lower income [27%], and households with limited access to private vehicles [34%]). ODT reduced total travel time by 32% compared with fixed-route transit, produced 2.4 to 4.3 times less greenhouse gas emissions per passenger mile (compared with transit and TNCs), and was more affordable (free to users) than alternative options ($1 for transit, $10 to $12 for TNCs). Overall satisfaction rates were high, with 80% of respondents rating the service a 4 or 5 out of 5.
{"title":"Community Public Mobility Using On-Demand, Low-Speed Electric Vehicles: A Case Study in Downtown St. Louis, Missouri","authors":"Johnny Esteban, Rick Grahn, Bonnie Powell, Stanley E. Young","doi":"10.1177/03611981241262306","DOIUrl":"https://doi.org/10.1177/03611981241262306","url":null,"abstract":"Legacy fixed-route transit systems designed to serve commuters struggle to provide efficient and effective service for short neighborhood trips and for population groups unable to access and egress transit stops using active modes (e.g., elderly, disabled). Neighborhood on-demand transit (ODT) services using low-speed electric vehicles (LSEVs) are an innovative technological solution that could help fill this gap in service (e.g., short, high-frequency trips) for diverse populations and trip types. This study evaluated user characteristics and travel behavior for a neighborhood ODT service (using LSEVs) in downtown St. Louis, MO, using responses from a community survey ( n = 244), ridership data, and vehicle trajectory information. A comparative analysis between neighborhood ODT, fixed-route transit, and transportation network companies (TNCs) was also conducted from the perspectives of total travel time, cost, and greenhouse gas emissions. Ultimately, the goal of the analysis was to motivate and inform holistic public mobility systems where different services are optimized to meet specific community needs. Findings indicate that the neighborhood ODT was effective at reaching diverse populations (elderly [20%], lower income [27%], and households with limited access to private vehicles [34%]). ODT reduced total travel time by 32% compared with fixed-route transit, produced 2.4 to 4.3 times less greenhouse gas emissions per passenger mile (compared with transit and TNCs), and was more affordable (free to users) than alternative options ($1 for transit, $10 to $12 for TNCs). Overall satisfaction rates were high, with 80% of respondents rating the service a 4 or 5 out of 5.","PeriodicalId":517391,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":"74 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867433","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 : 2024-07-30DOI: 10.1177/03611981241257503
Fazıl Gökgöz, Engin Yalçın
The transportation sector is a major cause of environmental deterioration and a key source of economic growth. A thorough balance should be provided between economic growth and energy consumption for long-term sustainability. In this regard, multi-criteria decision-making (MCDM) and Malmquist productivity index (MPI) techniques, which can deal with conflicting criteria simultaneously and determine productivity changes, respectively, were employed. In addition, ingrained and novel MCDM approaches simultaneously evaluated European Union (EU) countries’ transport sustainability. EU countries were driven into two equal groups based on their economic development level. Both MCDM techniques are in harmony as regards performance rankings for both groups. MCDM results indicate that highly industrialized members of the EU, such as Germany and France, are top performers as regards transportation sustainability level. The MPI technique findings show that Germany and Poland stand out with their effective dynamic performance figures. In conclusion, Germany performs well as regards both static and dynamic performance. In the transportation field, decision techniques enable stakeholders and decision-makers to construct comprehensive management plans and attain a nuanced understanding of industry performance and productivity.
{"title":"Performance and Productivity Analysis of the European Union Transport Sector: Evidence on Static and Dynamic Decision Models","authors":"Fazıl Gökgöz, Engin Yalçın","doi":"10.1177/03611981241257503","DOIUrl":"https://doi.org/10.1177/03611981241257503","url":null,"abstract":"The transportation sector is a major cause of environmental deterioration and a key source of economic growth. A thorough balance should be provided between economic growth and energy consumption for long-term sustainability. In this regard, multi-criteria decision-making (MCDM) and Malmquist productivity index (MPI) techniques, which can deal with conflicting criteria simultaneously and determine productivity changes, respectively, were employed. In addition, ingrained and novel MCDM approaches simultaneously evaluated European Union (EU) countries’ transport sustainability. EU countries were driven into two equal groups based on their economic development level. Both MCDM techniques are in harmony as regards performance rankings for both groups. MCDM results indicate that highly industrialized members of the EU, such as Germany and France, are top performers as regards transportation sustainability level. The MPI technique findings show that Germany and Poland stand out with their effective dynamic performance figures. In conclusion, Germany performs well as regards both static and dynamic performance. In the transportation field, decision techniques enable stakeholders and decision-makers to construct comprehensive management plans and attain a nuanced understanding of industry performance and productivity.","PeriodicalId":517391,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":"158 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867510","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 : 2024-07-30DOI: 10.1177/03611981241264271
Panick Kalambay, Srinivas S. Pulugurtha
Pedestrian safety is a long-standing issue in urban areas, where pedestrian near-crash events are more frequent than in suburban or rural areas. To address the pedestrian safety problem, a proactive approach was explored to assess and predict the severity of these events, which are valuable indicators of potential crashes. Object detection and tracking techniques were used to establish the temporal relationship of pedestrian near-crash events involving vehicles at an intersection controlled with rectangular rapid flashing beacons. A long short-term memory (LSTM) neural network model is proposed to warn a driver 2 s before the vehicle reaches the conflict zone. However, this scenario can be considered optimistic, as the 2 s interval represents an ideal driver’s reaction time, which is more likely to happen in a connected and automated vehicle environment where vehicles receive real-time information about their surroundings and perform some basic tasks such as braking without waiting for the driver reaction. The results demonstrate the effectiveness of the proposed LSTM neural network model, with an area under the curve value of 78.5% on the training data and an overall recall of 71.1% on the test data. The practical significance of this model is its potential to provide timely information about near-crash events, thereby enhancing pedestrian safety at critical points such as intersections.
{"title":"Modeling Pedestrian Near-Crash Events at a Rectangular Rapid Flashing Beacon-Controlled Intersection Using Video Analytics and Long Short-Term Memory Neural Network","authors":"Panick Kalambay, Srinivas S. Pulugurtha","doi":"10.1177/03611981241264271","DOIUrl":"https://doi.org/10.1177/03611981241264271","url":null,"abstract":"Pedestrian safety is a long-standing issue in urban areas, where pedestrian near-crash events are more frequent than in suburban or rural areas. To address the pedestrian safety problem, a proactive approach was explored to assess and predict the severity of these events, which are valuable indicators of potential crashes. Object detection and tracking techniques were used to establish the temporal relationship of pedestrian near-crash events involving vehicles at an intersection controlled with rectangular rapid flashing beacons. A long short-term memory (LSTM) neural network model is proposed to warn a driver 2 s before the vehicle reaches the conflict zone. However, this scenario can be considered optimistic, as the 2 s interval represents an ideal driver’s reaction time, which is more likely to happen in a connected and automated vehicle environment where vehicles receive real-time information about their surroundings and perform some basic tasks such as braking without waiting for the driver reaction. The results demonstrate the effectiveness of the proposed LSTM neural network model, with an area under the curve value of 78.5% on the training data and an overall recall of 71.1% on the test data. The practical significance of this model is its potential to provide timely information about near-crash events, thereby enhancing pedestrian safety at critical points such as intersections.","PeriodicalId":517391,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":"210 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867511","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 : 2024-07-30DOI: 10.1177/03611981241254387
Anas Abualia, Jun Liu, Louay N. Mohammad, Samuel B. Cooper, Samuel B. Cooper
Open-graded friction course (OGFC) is a thin asphalt mixture surface layer. It is gap-graded with a high percentage of coarse aggregates that are nearly uniform in size, resulting in a high percentage of interconnected air voids and asphalt binder, which provides improved skid resistance, visibility, and decreased pavement–tire noise. However, construction personnel at the Louisiana Department of Transportation and Development reported that conventional OGFC mixtures have durability issues and shorter service life, compared with thin asphalt mixture lifts. Hence, effects of different asphalt binder types on the performance of OGFC mixtures were evaluated. Five types of asphalt binder were utilized: conventional styrene-butadiene-styrene (SBS) asphalt binder PG 76-22M; high SBS content asphalt binder PG 88-28; diluted epoxy asphalt (EA) binder with two different dosages (25% and 50%); and a hybrid modified asphalt binder prepared with SBS and crumb rubber modifier PG 76-22G. The optimal aggregate structures were determined based on minimum required air voids and voids in coarse aggregate. Physical and mechanical tests were conducted to assess the performance of OGFC mixtures, including draindown, permeability, loaded wheel track, and Cantabro abrasion loss. Results indicate that OGFC mixtures incorporating diluted EA binder exhibited lower draindown values than mixtures containing PG 76-22M and PG 88-28. Moreover, mixtures with PG 88-28 and 50% EA binders demonstrated improved resistance to rutting. Mixtures with 50% EA and PG 88-28 binders demonstrated improved durability, compared with mixtures with PG 76-22M for unaged and aged conditioning, as measured by Cantabro abrasion loss values.
开级配摩擦层（OGFC）是一种薄的沥青混合料面层。它采用高比例的粗集料进行间隙级配，这些粗集料的尺寸几乎均匀一致，从而产生了高比例的相互连接的空气空隙和沥青粘结剂，从而提高了抗滑性、能见度并降低了路面轮胎噪音。然而，路易斯安那州交通与发展部的施工人员报告说，与稀薄沥青混合料相比，传统的 OGFC 混合料存在耐久性问题，使用寿命较短。因此，对不同类型的沥青粘结剂对 OGFC 混合物性能的影响进行了评估。研究使用了五种沥青粘结剂：传统的苯乙烯-丁二烯-苯乙烯（SBS）沥青粘结剂 PG 76-22M；高 SBS 含量沥青粘结剂 PG 88-28；两种不同添加量（25% 和 50%）的稀释环氧沥青（EA）粘结剂；以及使用 SBS 和橡胶屑改性剂制备的混合改性沥青粘结剂 PG 76-22G。根据所需的最小气隙和粗集料中的空隙确定了最佳集料结构。为评估 OGFC 混合物的性能，进行了物理和机械测试，包括降水、渗透性、加载轮迹和 Cantabro 磨损率。结果表明，与含有 PG 76-22M 和 PG 88-28 的混合物相比，含有稀释 EA 粘结剂的 OGFC 混合物显示出较低的降水值。此外，含有 PG 88-28 和 50% EA 粘结剂的混合物的抗车辙能力也有所提高。与使用 PG 76-22M 的混合物相比，使用 50％ EA 和 PG 88-28 粘结剂的混合物在未老化和老化条件下的耐久性有所提高，这是用 Cantabro 磨损率值来衡量的。
{"title":"Effect of High Polymer, Crumb Rubber, and Epoxy-Modified Asphalt Binders on Laboratory Performance of Open-Graded Friction Course Mixtures","authors":"Anas Abualia, Jun Liu, Louay N. Mohammad, Samuel B. Cooper, Samuel B. Cooper","doi":"10.1177/03611981241254387","DOIUrl":"https://doi.org/10.1177/03611981241254387","url":null,"abstract":"Open-graded friction course (OGFC) is a thin asphalt mixture surface layer. It is gap-graded with a high percentage of coarse aggregates that are nearly uniform in size, resulting in a high percentage of interconnected air voids and asphalt binder, which provides improved skid resistance, visibility, and decreased pavement–tire noise. However, construction personnel at the Louisiana Department of Transportation and Development reported that conventional OGFC mixtures have durability issues and shorter service life, compared with thin asphalt mixture lifts. Hence, effects of different asphalt binder types on the performance of OGFC mixtures were evaluated. Five types of asphalt binder were utilized: conventional styrene-butadiene-styrene (SBS) asphalt binder PG 76-22M; high SBS content asphalt binder PG 88-28; diluted epoxy asphalt (EA) binder with two different dosages (25% and 50%); and a hybrid modified asphalt binder prepared with SBS and crumb rubber modifier PG 76-22G. The optimal aggregate structures were determined based on minimum required air voids and voids in coarse aggregate. Physical and mechanical tests were conducted to assess the performance of OGFC mixtures, including draindown, permeability, loaded wheel track, and Cantabro abrasion loss. Results indicate that OGFC mixtures incorporating diluted EA binder exhibited lower draindown values than mixtures containing PG 76-22M and PG 88-28. Moreover, mixtures with PG 88-28 and 50% EA binders demonstrated improved resistance to rutting. Mixtures with 50% EA and PG 88-28 binders demonstrated improved durability, compared with mixtures with PG 76-22M for unaged and aged conditioning, as measured by Cantabro abrasion loss values.","PeriodicalId":517391,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867431","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 : 2024-07-30DOI: 10.1177/03611981241253608
Matthew D. Dean, Kara M. Kockelman
An increasing number of battery-electric vehicles (BEVs) have bidirectional charging technology that provides new benefits to motorists, homeowners, and power grid operators. A web-based survey investigates the willingness of over 300 Americans to pay for added bidirectional charging features, namely, vehicle-to-load (V2L), vehicle-to-home (V2H), and vehicle-to-grid (V2G) technologies, along with their expected use frequency. Summary statistics suggest that Americans are willing to pay (WTP) an average of $280 and $776 on top of the price of a new car for V2L and V2H, respectively. About 51.3% would let their power company discharge their vehicle via V2G during grid emergencies if compensated and guaranteed a minimum battery level. Interval regression and ordered probit equations explain how demographics, travel patterns, and attitudinal variables affect the response variables, including WTP for bidirectional charging features and expected reliance on technology. The statistically and practically significant relationships suggest that adults over 34 have lower WTP values for V2L and V2H, and those in households with more vehicles plan on more bi-directional charging, as expected. The findings have implications for policymakers, manufacturers, and stakeholders involved in the BEV ecosystem, informing their decision-making processes related to integrating and commercializing bidirectional charging technologies. These models may even help power grid planners understand who is likely to adopt V2G technology, enabling them to aggregate and shift BEV loads to help manage the grid in parallel and isolation.
{"title":"Assessing Public Opinions of and Interest in Bidirectional Electric Vehicle Charging Technologies: A U.S. Perspective","authors":"Matthew D. Dean, Kara M. Kockelman","doi":"10.1177/03611981241253608","DOIUrl":"https://doi.org/10.1177/03611981241253608","url":null,"abstract":"An increasing number of battery-electric vehicles (BEVs) have bidirectional charging technology that provides new benefits to motorists, homeowners, and power grid operators. A web-based survey investigates the willingness of over 300 Americans to pay for added bidirectional charging features, namely, vehicle-to-load (V2L), vehicle-to-home (V2H), and vehicle-to-grid (V2G) technologies, along with their expected use frequency. Summary statistics suggest that Americans are willing to pay (WTP) an average of $280 and $776 on top of the price of a new car for V2L and V2H, respectively. About 51.3% would let their power company discharge their vehicle via V2G during grid emergencies if compensated and guaranteed a minimum battery level. Interval regression and ordered probit equations explain how demographics, travel patterns, and attitudinal variables affect the response variables, including WTP for bidirectional charging features and expected reliance on technology. The statistically and practically significant relationships suggest that adults over 34 have lower WTP values for V2L and V2H, and those in households with more vehicles plan on more bi-directional charging, as expected. The findings have implications for policymakers, manufacturers, and stakeholders involved in the BEV ecosystem, informing their decision-making processes related to integrating and commercializing bidirectional charging technologies. These models may even help power grid planners understand who is likely to adopt V2G technology, enabling them to aggregate and shift BEV loads to help manage the grid in parallel and isolation.","PeriodicalId":517391,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867507","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 : 2024-07-30DOI: 10.1177/03611981241254382
Subham Kharel, Seyedsoheil Sharifiasl, Qisheng Pan
Accessibility to food stores offering nutritious and affordable options is critical to ensure urban residents lead healthy lives. However, the uneven distribution of diverse food options in U.S. cities has raised concerns about marginalized communities’ ability to obtain affordable and nutritious food. Transportation-related issues, like car-oriented urban form and sprawl, have created food deserts in cities, making it hard for marginalized communities to access affordable and healthy food. This lack of access has recently drawn the attention of urban planners to address food access-related equity issues. Spatial interaction models can help measure food access by examining how grocery store supply, demand, and proximity affect individuals’ access to necessary food. However, these measures do not always consider the pricing of food items, which can significantly affect food access for low-income individuals and families. We use a highly disaggregated measure tailored to measuring inequitable food accessibility by factoring grocery store pricing into various types of supply and demand. Then, using regional socio-demographic thresholds, we identify target population groups and perform a series of equity analyses using our food accessibility measure. Our results show that walking is more inequitable than driving to food stores and that African American and Hispanic minorities, the elderly, and carless households are more burdened than the reference groups (whites). Using our framework, we identify food deserts and provide spatial and empirical insights for policymakers and planners to address food insecurity and promote equitable access to healthy food.
{"title":"Examining Food Access Equity by Integrating Grocery Store Pricing into Spatial Accessibility Measures","authors":"Subham Kharel, Seyedsoheil Sharifiasl, Qisheng Pan","doi":"10.1177/03611981241254382","DOIUrl":"https://doi.org/10.1177/03611981241254382","url":null,"abstract":"Accessibility to food stores offering nutritious and affordable options is critical to ensure urban residents lead healthy lives. However, the uneven distribution of diverse food options in U.S. cities has raised concerns about marginalized communities’ ability to obtain affordable and nutritious food. Transportation-related issues, like car-oriented urban form and sprawl, have created food deserts in cities, making it hard for marginalized communities to access affordable and healthy food. This lack of access has recently drawn the attention of urban planners to address food access-related equity issues. Spatial interaction models can help measure food access by examining how grocery store supply, demand, and proximity affect individuals’ access to necessary food. However, these measures do not always consider the pricing of food items, which can significantly affect food access for low-income individuals and families. We use a highly disaggregated measure tailored to measuring inequitable food accessibility by factoring grocery store pricing into various types of supply and demand. Then, using regional socio-demographic thresholds, we identify target population groups and perform a series of equity analyses using our food accessibility measure. Our results show that walking is more inequitable than driving to food stores and that African American and Hispanic minorities, the elderly, and carless households are more burdened than the reference groups (whites). Using our framework, we identify food deserts and provide spatial and empirical insights for policymakers and planners to address food insecurity and promote equitable access to healthy food.","PeriodicalId":517391,"journal":{"name":"Transportation Research Record: Journal of the Transportation Research Board","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141867429","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}
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