Pub Date : 2023-09-29DOI: 10.1177/03611981231198464
Sevgi Erdoğan, Amir Nohekhan, Alibi Shokputov, Kaveh Farokhi Sadabadi
The paper addresses a critical research gap in the literature by focusing on the identification of service areas for microtransit. It presents a framework for identifying areas where microtransit would have a higher potential for success. The primary objective is to assist agencies in their efforts to provide microtransit services by offering a robust and flexible decision-making framework. This framework serves as an intermediate step between an initial planning study that identifies candidate zones and a detailed feasibility study, which is currently missing in the literature. The framework is a multi-criteria decision-making (MCDM) process that can be applicable to various contexts. Specifically, our approach utilizes a lexicographic decision rule for ranking microtransit service priority measures for each census block of a selected region, such as a county. We employ two composite measures for ranking: Microtransit Propensity Index (MPI) and Weighted Accessibility Score (WAS). The latter combines transit access to work and to eight points of interest (POIs). This framework can be adapted to identify zones suitable for microtransit service based on different objectives, such as connecting residents to transit centers, providing first- and last-mile connections, providing services in transit deserts, providing flexible transit service to low-income communities, or providing access to the POIs within a zone. The effectiveness of the proposed framework is evaluated using the case of Prince George’s County in Maryland. The results reveal that our approach provides greater insights into the feasibility of an area for microtransit compared with relying solely on a single index such as MPI.
{"title":"Multi-Criteria Decision-Making Framework for Determining Public Microtransit Service Zones","authors":"Sevgi Erdoğan, Amir Nohekhan, Alibi Shokputov, Kaveh Farokhi Sadabadi","doi":"10.1177/03611981231198464","DOIUrl":"https://doi.org/10.1177/03611981231198464","url":null,"abstract":"The paper addresses a critical research gap in the literature by focusing on the identification of service areas for microtransit. It presents a framework for identifying areas where microtransit would have a higher potential for success. The primary objective is to assist agencies in their efforts to provide microtransit services by offering a robust and flexible decision-making framework. This framework serves as an intermediate step between an initial planning study that identifies candidate zones and a detailed feasibility study, which is currently missing in the literature. The framework is a multi-criteria decision-making (MCDM) process that can be applicable to various contexts. Specifically, our approach utilizes a lexicographic decision rule for ranking microtransit service priority measures for each census block of a selected region, such as a county. We employ two composite measures for ranking: Microtransit Propensity Index (MPI) and Weighted Accessibility Score (WAS). The latter combines transit access to work and to eight points of interest (POIs). This framework can be adapted to identify zones suitable for microtransit service based on different objectives, such as connecting residents to transit centers, providing first- and last-mile connections, providing services in transit deserts, providing flexible transit service to low-income communities, or providing access to the POIs within a zone. The effectiveness of the proposed framework is evaluated using the case of Prince George’s County in Maryland. The results reveal that our approach provides greater insights into the feasibility of an area for microtransit compared with relying solely on a single index such as MPI.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135247589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-28DOI: 10.1177/03611981231187641
Marcus S. Dersch, Max Potvin, Arthur de O. Lima, J. Riley Edwards
As extreme temperatures increase, there is an increased need to ensure that continuous welded rail (CWR) stresses are more accurately set and better maintained. Therefore, to improve the management of CWR rail stresses and to increase safety through the reduction of buckled track derailments this paper documents the results from a field experimentation program of controlled single rail breaks (SRBs). SRBs were conducted at multiple field site locations to quantify the longitudinal resistance on both timber and concrete sleeper track. Accurate longitudinal resistance values are critical, because if the wrong value is selected, the rail neutral temperature could easily be set to a low value, increasing the probability of a track buckle or rail pull-apart, further compounding the impact of extreme temperatures. The results presented quantify the effect of sleeper and fastener type as well as ballast consolidation, and compare them with relevant results from the literature. From this, it was found that well-maintained concrete sleeper track exhibited a longitudinal resistance greater than the currently recommended value. Further, well-maintained timber sleeper track with anchors on every other sleeper exhibited a longitudinal resistance 44% lower than concrete sleeper track and 30% lower than timber track with anchors installed on every sleeper. Additionally, disturbing the ballast reduced the longitudinal resistance by 15%. Finally, the results indicated that slip was primarily occurring at the rail–sleeper interface for unanchored timber sleepers and at the sleeper–ballast interface for anchored timber sleepers and concrete sleepers.
{"title":"Effect of Critical Factors Influencing Longitudinal Track Resistance Leveraging Field Experimentation","authors":"Marcus S. Dersch, Max Potvin, Arthur de O. Lima, J. Riley Edwards","doi":"10.1177/03611981231187641","DOIUrl":"https://doi.org/10.1177/03611981231187641","url":null,"abstract":"As extreme temperatures increase, there is an increased need to ensure that continuous welded rail (CWR) stresses are more accurately set and better maintained. Therefore, to improve the management of CWR rail stresses and to increase safety through the reduction of buckled track derailments this paper documents the results from a field experimentation program of controlled single rail breaks (SRBs). SRBs were conducted at multiple field site locations to quantify the longitudinal resistance on both timber and concrete sleeper track. Accurate longitudinal resistance values are critical, because if the wrong value is selected, the rail neutral temperature could easily be set to a low value, increasing the probability of a track buckle or rail pull-apart, further compounding the impact of extreme temperatures. The results presented quantify the effect of sleeper and fastener type as well as ballast consolidation, and compare them with relevant results from the literature. From this, it was found that well-maintained concrete sleeper track exhibited a longitudinal resistance greater than the currently recommended value. Further, well-maintained timber sleeper track with anchors on every other sleeper exhibited a longitudinal resistance 44% lower than concrete sleeper track and 30% lower than timber track with anchors installed on every sleeper. Additionally, disturbing the ballast reduced the longitudinal resistance by 15%. Finally, the results indicated that slip was primarily occurring at the rail–sleeper interface for unanchored timber sleepers and at the sleeper–ballast interface for anchored timber sleepers and concrete sleepers.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135425632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-22DOI: 10.1177/03611981231198475
Saurav Parajuli, Christopher R. Cherry, Ellen Zavisca, William Rogers
Similar to the nationwide trend of declining pedestrian safety, pedestrian fatalities in Tennessee increased by 117 % between 2009 and 2019. During the same time, pedestrians involved in traffic crashes have only increased by 26 %, suggesting that the reason for the increased number of fatalities is that pedestrian crashes are becoming more severe. The media, and safety advocates speculate about the different scenarios that could be responsible for the decrease in pedestrian safety. Past studies have failed to integrate pedestrian involvement into their studies and confirm whether pedestrian crashes are becoming more severe. Our study collected all reported pedestrian crashes and their outcomes from crash data kept by the Tennessee police, thus providing fatality and involvement numbers. Excluding crashes on controlled access roads, we measured the pedestrian fatality rate (PFR) for essential variables for each year from 2009 to 2019. An upward PFR graph shows that pedestrian crashes are becoming more severe compared with the past. To substantiate our claims with adequate statistical significance, we employed separate Poisson regression models for the pedestrian fatality count and PFR associated with each attribute of pedestrian crashes. The results show that an increase in severity is linked with multilane urban arterials with speeds above 35 mph at midblock locations. The study results also confirm that cars are still the cause of the high fatality rate in Tennessee rather than sport utility vehicles or other large vehicles. We recommend that cities reduce design speeds to 35 mph, increase safe pedestrian crossing opportunities, and install more pedestrian-scale lighting infrastructure on urban arterials.
{"title":"Are Pedestrian Crashes Becoming More Severe? A Breakdown of Pedestrian Crashes in Urban Tennessee","authors":"Saurav Parajuli, Christopher R. Cherry, Ellen Zavisca, William Rogers","doi":"10.1177/03611981231198475","DOIUrl":"https://doi.org/10.1177/03611981231198475","url":null,"abstract":"Similar to the nationwide trend of declining pedestrian safety, pedestrian fatalities in Tennessee increased by 117 % between 2009 and 2019. During the same time, pedestrians involved in traffic crashes have only increased by 26 %, suggesting that the reason for the increased number of fatalities is that pedestrian crashes are becoming more severe. The media, and safety advocates speculate about the different scenarios that could be responsible for the decrease in pedestrian safety. Past studies have failed to integrate pedestrian involvement into their studies and confirm whether pedestrian crashes are becoming more severe. Our study collected all reported pedestrian crashes and their outcomes from crash data kept by the Tennessee police, thus providing fatality and involvement numbers. Excluding crashes on controlled access roads, we measured the pedestrian fatality rate (PFR) for essential variables for each year from 2009 to 2019. An upward PFR graph shows that pedestrian crashes are becoming more severe compared with the past. To substantiate our claims with adequate statistical significance, we employed separate Poisson regression models for the pedestrian fatality count and PFR associated with each attribute of pedestrian crashes. The results show that an increase in severity is linked with multilane urban arterials with speeds above 35 mph at midblock locations. The study results also confirm that cars are still the cause of the high fatality rate in Tennessee rather than sport utility vehicles or other large vehicles. We recommend that cities reduce design speeds to 35 mph, increase safe pedestrian crossing opportunities, and install more pedestrian-scale lighting infrastructure on urban arterials.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136061030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-21DOI: 10.1177/03611981231198838
Mustafa Ekmekci, Renan Sinanmis, Lee Woods
Highway pavements deteriorate over time as successive wheel loads cause rutting, cracking, texture loss, and so forth. Design standards and pavement performance models account for some of the known contributory factors, such as levels of traffic and vehicle composition. However, such models are limited in their predictive power, and highway authorities must conduct regular pavement condition surveys rather than relying on the standard deterioration models alone. The ways in which multiple factors affect pavement deterioration, including rutting, are complex and are believed to include feedback loops where rutting then influences driving position, exacerbating the rutting levels. Standard regression models are not well suited to representing such complex causal mechanisms. This paper compares two alternative modeling approaches, structural equation models and auto-machine learning, and evaluates the predictive ability and practicalities of each. The findings indicate that auto-machine learning (AutoML) may be superior in its predictive ability. However, the “black box” nature of AutoML results makes them potentially less useful to practitioners. A process of using machine learning to help inform a structural equation model is proposed.
{"title":"Predictive Modeling for Highway Pavement Rutting: A Comparative Analysis of Auto-Machine Learning and Structural Equation Models","authors":"Mustafa Ekmekci, Renan Sinanmis, Lee Woods","doi":"10.1177/03611981231198838","DOIUrl":"https://doi.org/10.1177/03611981231198838","url":null,"abstract":"Highway pavements deteriorate over time as successive wheel loads cause rutting, cracking, texture loss, and so forth. Design standards and pavement performance models account for some of the known contributory factors, such as levels of traffic and vehicle composition. However, such models are limited in their predictive power, and highway authorities must conduct regular pavement condition surveys rather than relying on the standard deterioration models alone. The ways in which multiple factors affect pavement deterioration, including rutting, are complex and are believed to include feedback loops where rutting then influences driving position, exacerbating the rutting levels. Standard regression models are not well suited to representing such complex causal mechanisms. This paper compares two alternative modeling approaches, structural equation models and auto-machine learning, and evaluates the predictive ability and practicalities of each. The findings indicate that auto-machine learning (AutoML) may be superior in its predictive ability. However, the “black box” nature of AutoML results makes them potentially less useful to practitioners. A process of using machine learning to help inform a structural equation model is proposed.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136235766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Park and ride facilities can be a potential instrument for addressing the rising congestion problems and ensuring sustainable urban mobility in major Indian cities, equipped with fast and excellent metro systems. The present study attempts to understand the travel behavior of commuters (four-wheeled private vehicle users only) in relation to the introduction of park and ride as a sustainable and economical alternative mode of travel to driving alone in a private vehicle in the context of Delhi, India. The present study measures the perceived benefit to drive-alone users in Delhi with regard to their willingness to pay (WTP) for switching to a better-quality park and ride service instead of using their private vehicles. Choice-based responses along with socioeconomic and travel information were collected from 559 drive-alone users using a tablet-based stated preference survey instrument. The responses were then analyzed using a multinomial logit (MNL) model. Further, WTP estimates of the noncost attributes were calculated to derive the perceived benefit to drive-alone users if they were to switch to using a park and ride service. The study also developed a generalized cost (GC) equation using the parameter and WTP estimates derived from the MNL model. Finally, the study conducted a post-estimation analysis using the GC equation to examine the influences of identified explanatory attributes on the GC for drive-alone users who switched to park and ride. “Trip length,”“parking cost,” and “parking type” exerted a significant influence on the generalized cost, indicating that drive-alone users could expect considerable savings (perceived benefit with regard to utility gain) if they were to choose park and ride.
{"title":"Stated Preference Approach for Measuring the Perceived Benefit to Drive-Alone Users If They Switch to Park and Ride: An Indian Perspective","authors":"Manaswinee Kar, Shubhajit Sadhukhan, Manoranjan Parida, Arpit Shrivastava","doi":"10.1177/03611981231196150","DOIUrl":"https://doi.org/10.1177/03611981231196150","url":null,"abstract":"Park and ride facilities can be a potential instrument for addressing the rising congestion problems and ensuring sustainable urban mobility in major Indian cities, equipped with fast and excellent metro systems. The present study attempts to understand the travel behavior of commuters (four-wheeled private vehicle users only) in relation to the introduction of park and ride as a sustainable and economical alternative mode of travel to driving alone in a private vehicle in the context of Delhi, India. The present study measures the perceived benefit to drive-alone users in Delhi with regard to their willingness to pay (WTP) for switching to a better-quality park and ride service instead of using their private vehicles. Choice-based responses along with socioeconomic and travel information were collected from 559 drive-alone users using a tablet-based stated preference survey instrument. The responses were then analyzed using a multinomial logit (MNL) model. Further, WTP estimates of the noncost attributes were calculated to derive the perceived benefit to drive-alone users if they were to switch to using a park and ride service. The study also developed a generalized cost (GC) equation using the parameter and WTP estimates derived from the MNL model. Finally, the study conducted a post-estimation analysis using the GC equation to examine the influences of identified explanatory attributes on the GC for drive-alone users who switched to park and ride. “Trip length,”“parking cost,” and “parking type” exerted a significant influence on the generalized cost, indicating that drive-alone users could expect considerable savings (perceived benefit with regard to utility gain) if they were to choose park and ride.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136154340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-21DOI: 10.1177/03611981231191517
Zhengtao Lei, Hai Jiang, Shaosheng Cao, Lisheng Zhao
On-demand intra-city freight logistics (ICFL) has recently emerged as a new freight service, where shippers can submit their shipping requests using smartphones and be matched to drivers in real time based on their locations and drivers’ availability. A major challenge faced by on-demand ICFL platforms is the shortage of vehicles during peak demand periods. Cargo pooling, the cargo version of carpooling, offers as a promising way to increase supply: cargoes heading in the same direction would share the cargo compartment of the same vehicle and be serviced simultaneously, which is achieved by careful sequencing of the pickup and delivery locations of the cargoes. We investigate models for cargo pooling for on-demand ICFL and quantify its benefit, which is new to the literature. The major difference between existing studies on ICFL and ours is that we no longer assume that demands are known beforehand. Instead, the demands arrive gradually throughout the day and we need to periodically match requests to drivers and re-optimize vehicle routes. We formulate the matching problem as a dynamic pickup and delivery problem with three-dimensional loading and time window constraints. To solve this model, we develop an algorithm based on large neighborhood search and tree search. The algorithm is tested with real freight data in a city in the Yangtze River Delta. Results show that the algorithm can reduce the total cost by 21.4% and reduce the total vehicle miles traveled by 36.0%.
{"title":"Value of Cargo Pooling in On-Demand Intra-City Freight Logistics","authors":"Zhengtao Lei, Hai Jiang, Shaosheng Cao, Lisheng Zhao","doi":"10.1177/03611981231191517","DOIUrl":"https://doi.org/10.1177/03611981231191517","url":null,"abstract":"On-demand intra-city freight logistics (ICFL) has recently emerged as a new freight service, where shippers can submit their shipping requests using smartphones and be matched to drivers in real time based on their locations and drivers’ availability. A major challenge faced by on-demand ICFL platforms is the shortage of vehicles during peak demand periods. Cargo pooling, the cargo version of carpooling, offers as a promising way to increase supply: cargoes heading in the same direction would share the cargo compartment of the same vehicle and be serviced simultaneously, which is achieved by careful sequencing of the pickup and delivery locations of the cargoes. We investigate models for cargo pooling for on-demand ICFL and quantify its benefit, which is new to the literature. The major difference between existing studies on ICFL and ours is that we no longer assume that demands are known beforehand. Instead, the demands arrive gradually throughout the day and we need to periodically match requests to drivers and re-optimize vehicle routes. We formulate the matching problem as a dynamic pickup and delivery problem with three-dimensional loading and time window constraints. To solve this model, we develop an algorithm based on large neighborhood search and tree search. The algorithm is tested with real freight data in a city in the Yangtze River Delta. Results show that the algorithm can reduce the total cost by 21.4% and reduce the total vehicle miles traveled by 36.0%.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136154557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-21DOI: 10.1177/03611981231186989
Adjo Amekudzi-Kennedy, Prerna Singh, Emily Williams, Manuel Cuadra, Baabak Ashuri, Brian Woodall, Adair Garrett, Mandani Tennakoon, Russell Clark, Amalapurapu Dheeraj
Although definitions of resilience are wide-ranging, they ultimately aim to preserve functionality and performance during and after anticipated and unanticipated disruptions. Common themes for transportation system resilience include preparedness, robustness, response, and recovery. Adaptation is increasingly considered an important resilience ability for deeply uncertain conditions, and transformation an essential ability for sustainability. This paper discusses three factors that contribute to the development of resilience adaptively: (1) development of adaptive capabilities in an organization and its infrastructure systems to face known and unknown threats; (2) application of dynamic, adaptive, and robustness approaches in deeply uncertain conditions; and (3) mitigation of factors that cause or exacerbate unwanted disruptions to system function and performance—together with risk-based approaches to manage specific threats with well-understood likelihoods and consequences of occurrence. These factors enable an entity to adapt under deeply uncertain conditions—developing resilience as conditions change—and to adapt to curb the causes of disruptions. The benefits of developing resilience adaptively are to: enable the development of both threats-based and opportunities-based resilience; address deep uncertainties where it is impossible to quantify the chances and consequences of disruptions; and transition from merely managing symptoms to addressing the factors that cause, influence, or perpetuate them. These concepts are applied to develop an adaptive resilience improvement process for transportation agencies. This paper is potentially useful to practitioners interested in developing resilience adaptively and to researchers interested in risk-, adaptive and mitigation-based approaches to address known and unknown threats, for short- and long-term resilience gains.
{"title":"Developing Transportation Resilience Adaptively to Climate Change","authors":"Adjo Amekudzi-Kennedy, Prerna Singh, Emily Williams, Manuel Cuadra, Baabak Ashuri, Brian Woodall, Adair Garrett, Mandani Tennakoon, Russell Clark, Amalapurapu Dheeraj","doi":"10.1177/03611981231186989","DOIUrl":"https://doi.org/10.1177/03611981231186989","url":null,"abstract":"Although definitions of resilience are wide-ranging, they ultimately aim to preserve functionality and performance during and after anticipated and unanticipated disruptions. Common themes for transportation system resilience include preparedness, robustness, response, and recovery. Adaptation is increasingly considered an important resilience ability for deeply uncertain conditions, and transformation an essential ability for sustainability. This paper discusses three factors that contribute to the development of resilience adaptively: (1) development of adaptive capabilities in an organization and its infrastructure systems to face known and unknown threats; (2) application of dynamic, adaptive, and robustness approaches in deeply uncertain conditions; and (3) mitigation of factors that cause or exacerbate unwanted disruptions to system function and performance—together with risk-based approaches to manage specific threats with well-understood likelihoods and consequences of occurrence. These factors enable an entity to adapt under deeply uncertain conditions—developing resilience as conditions change—and to adapt to curb the causes of disruptions. The benefits of developing resilience adaptively are to: enable the development of both threats-based and opportunities-based resilience; address deep uncertainties where it is impossible to quantify the chances and consequences of disruptions; and transition from merely managing symptoms to addressing the factors that cause, influence, or perpetuate them. These concepts are applied to develop an adaptive resilience improvement process for transportation agencies. This paper is potentially useful to practitioners interested in developing resilience adaptively and to researchers interested in risk-, adaptive and mitigation-based approaches to address known and unknown threats, for short- and long-term resilience gains.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136154341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-21DOI: 10.1177/03611981231198467
Tristan Sanderson, Brent M. Phares, Katelyn S. Freeseman, Zhengyu Liu
Earth pressure on concrete box culverts is a key component of design and load-rating decisions. The American Association of State Highway and Transportation Officials has revised the design guidelines over the years to impose greater design/rating earth pressures for buried structures. Currently, the Iowa Department of Transportation uses the maximum and minimum lateral earth pressure of 36/18 lb/ft3 specified for load factor design (LFD) and allowable stress design (ASD) and 60/30 lb/ft3 for load and resistance factor design (LRFD). The objective of this research is to monitor and evaluate the real earth pressures acting on deep-buried culvert structures. To achieve this objective, two concrete box culverts–one in Ida County and the other in Crawford County–were monitored for more than 2.5 years and 1 year, respectively, to identify the realistic design soil pressure. The captured pressure, strain, and temperature data were analyzed to find the relation between the temperature and earth pressure experienced by the culverts. The measured vertical and lateral pressures were compared with the specified design pressure loading. The monitoring results from both culverts led to the consistent conclusion that the earth pressure experienced by the culverts was two to six times that of the design values with the LRFD and LFD/ASD methods. This paper revealed that the earth pressure acting on the deeply embedded culvert could be higher than the design-specified value. Further research was recommended to investigate the relation between the soil weight and culvert vertical/lateral pressure for Iowa design specifications.
{"title":"Evaluation of the Earth Pressure Acting on Concrete Box Culverts","authors":"Tristan Sanderson, Brent M. Phares, Katelyn S. Freeseman, Zhengyu Liu","doi":"10.1177/03611981231198467","DOIUrl":"https://doi.org/10.1177/03611981231198467","url":null,"abstract":"Earth pressure on concrete box culverts is a key component of design and load-rating decisions. The American Association of State Highway and Transportation Officials has revised the design guidelines over the years to impose greater design/rating earth pressures for buried structures. Currently, the Iowa Department of Transportation uses the maximum and minimum lateral earth pressure of 36/18 lb/ft3 specified for load factor design (LFD) and allowable stress design (ASD) and 60/30 lb/ft3 for load and resistance factor design (LRFD). The objective of this research is to monitor and evaluate the real earth pressures acting on deep-buried culvert structures. To achieve this objective, two concrete box culverts–one in Ida County and the other in Crawford County–were monitored for more than 2.5 years and 1 year, respectively, to identify the realistic design soil pressure. The captured pressure, strain, and temperature data were analyzed to find the relation between the temperature and earth pressure experienced by the culverts. The measured vertical and lateral pressures were compared with the specified design pressure loading. The monitoring results from both culverts led to the consistent conclusion that the earth pressure experienced by the culverts was two to six times that of the design values with the LRFD and LFD/ASD methods. This paper revealed that the earth pressure acting on the deeply embedded culvert could be higher than the design-specified value. Further research was recommended to investigate the relation between the soil weight and culvert vertical/lateral pressure for Iowa design specifications.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136154323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-21DOI: 10.1177/03611981231197643
Haoran Zheng, Soora Rasouli, Zhigang Du, Shoushuo Wang
To understand the relation between the geometric design of optically long tunnels and visibility of the exit area, in this study oculomotor (eye movement) data are collected from several drivers in Yunnan Province, China, and drivers’ fixation rate and saccade amplitude in the visible zone of the tunnel are measured as key indicators. The driver’s visual recognition is analyzed and key elements in the optimal design of the exit points of optically long tunnels are discussed. The results show that visual recognition is closely associated with the radius of the road curvature: as the radius of curve decreases, the visual focus is gradually attracted to the inner side of the curve, the proportion of small-angle saccade increases, and the dispersion of the saccade amplitude decreases.
{"title":"Visual Recognition Analysis of Optically Long Tunnels: Interaction of Dynamic Vision and Visual Perception","authors":"Haoran Zheng, Soora Rasouli, Zhigang Du, Shoushuo Wang","doi":"10.1177/03611981231197643","DOIUrl":"https://doi.org/10.1177/03611981231197643","url":null,"abstract":"To understand the relation between the geometric design of optically long tunnels and visibility of the exit area, in this study oculomotor (eye movement) data are collected from several drivers in Yunnan Province, China, and drivers’ fixation rate and saccade amplitude in the visible zone of the tunnel are measured as key indicators. The driver’s visual recognition is analyzed and key elements in the optimal design of the exit points of optically long tunnels are discussed. The results show that visual recognition is closely associated with the radius of the road curvature: as the radius of curve decreases, the visual focus is gradually attracted to the inner side of the curve, the proportion of small-angle saccade increases, and the dispersion of the saccade amplitude decreases.","PeriodicalId":23279,"journal":{"name":"Transportation Research Record","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136154564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-20DOI: 10.1177/03611981231195056
Guangchuan Yang, Christopher M. Cunningham, Michael R. Brown
A quadrant roadway intersection (QRI) reduces congestion relative to a four-phase intersection. (Note: this study relates to traffic systems where vehicles drive on the right-hand side of the road.) It does this by removing left-turn traffic from the main intersection, resulting in a two-phase signal. Nevertheless, there is a lack of clear understanding of the tradeoffs between savings in control delay versus extra travel time experienced by the rerouted movements. This research compared the operational performance of five QRI designs with the counterpart conventional intersection (CI) under various traffic demand scenarios via TransModeler microsimulation modeling. Three measures-of-effectiveness (MOEs) were employed: time-in-system (TIS), control delay, and intersection capacity utilization. Simulation results show that all QRI designs outperform CI design for all three MOEs under all demand scenarios. QRIs with direct left-turn design have a smaller average TIS than those with loop left-turn design, indicating that savings in control delays did not offset the extra travel times. Under a relatively low demand condition, a single QRI design can generally balance the tradeoffs between control delay and extra travel time. Under a high demand scenario, a dual or full QRI with direct left-turns is preferred, since it reroutes or partially reroutes left- and right-turn traffic to secondary intersections, thus the main intersection has a lower capacity utilization and can accommodate more through-traffic demands than CI, single QRI, and dual or full QRIs with loop left-turns.
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