The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Tarek Sayed - One of the best experts on this subject based on the ideXlab platform.
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exploring Evasive Action based indicators for ptw conflicts in shared traffic facility environments
Journal of Transportation Engineering Part A: Systems, 2018Co-Authors: Yanyong Guo, Tarek Sayed, Mohamed H ZakiAbstract:AbstractSurrogate safety measures such as traffic conflicts are gaining more and more attention for traffic safety analysis. The traffic conflict technique evaluates the frequency and severity of t...
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Exploring Evasive Action–Based Indicators for PTW Conflicts in Shared Traffic Facility Environments
Journal of Transportation Engineering Part A: Systems, 2018Co-Authors: Yanyong Guo, Tarek Sayed, Mohamed H ZakiAbstract:AbstractSurrogate safety measures such as traffic conflicts are gaining more and more attention for traffic safety analysis. The traffic conflict technique evaluates the frequency and severity of t...
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Comparison of Time-Proximity and Evasive Action Conflict Measures: Case Studies from Five Cities:
Transportation Research Record: Journal of the Transportation Research Board, 2017Co-Authors: Ahmed Tageldin, Tarek Sayed, Khaled ShaabanAbstract:Interest has grown in using traffic conflicts for studying safety from a broader perspective than relying only on collision data. Traffic conflict analysis is typically performed through the calculation of traditional conflict severity measures such as time-to-collision and postencroachment time. These measures rely on road users getting within specific temporal and spatial proximity from each other and therefore assume that proximity is the surrogate for severity. However, this assumption may not be valid in some driving environments where close interActions between road users are common and sudden Evasive Actions are frequently used to avoid collisions. It is suggested that Evasive Action–based conflict indicators can assess the analysis in some less-organized traffic environments. This study focused on the severity evaluation of pedestrian conflicts. Pedestrian Evasive Actions were reflected mainly in variations of spatiotemporal gait parameters (step frequency and step length). The objective was to co...
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Developing Evasive Action‐based indicators for identifying pedestrian conflicts in less organized traffic environments
Journal of Advanced Transportation, 2016Co-Authors: Ahmed Tageldin, Tarek SayedAbstract:Summary There has been a growing interest in using surrogate safety measures such as traffic conflicts to analyse road safety from a broader perspective than collision data alone. This growing interest has been aided by recent advances in automated video-based traffic conflict analysis. The automation enables accurate calculation of various conflict indicators such as time-to-collision and post-encroachment time. These indicators rely on road users getting within specific temporal and spatial proximity from each other and therefore assume that proximity is a surrogate for conflict severity. However, this assumption may not be valid in many driving environments where close interActions between road users are common. The objective of this paper is to investigate the applicability of time proximity conflict indicators for evaluating pedestrian safety in less-organized traffic environments with a high mix of road users. Several alternative behavioural conflict indicators based on detecting pedestrian Evasive Actions are recommended to better measure traffic conflicts in such traffic environments. These indicators represent variations in the spatio-temporal gait parameters (step length, step frequency and walk ratio) immediately before the conflict point. A highly congested shared intersection in Shanghai, China, with frequent pedestrian conflicts is used as a case study. Traffic conflicts are analysed with the use of automated video-based analysis techniques. The results showed that Evasive Action-based indicators have higher potential to identify pedestrian conflicts and measure their severity in high mix less organized traffic environments than time proximity measures such as time-to-collision and post-encroachment time. Copyright © 2016 John Wiley & Sons, Ltd.
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developing Evasive Action based indicators for identifying pedestrian conflicts in less organized traffic environments
Journal of Advanced Transportation, 2016Co-Authors: Ahmed Tageldin, Tarek SayedAbstract:Summary There has been a growing interest in using surrogate safety measures such as traffic conflicts to analyse road safety from a broader perspective than collision data alone. This growing interest has been aided by recent advances in automated video-based traffic conflict analysis. The automation enables accurate calculation of various conflict indicators such as time-to-collision and post-encroachment time. These indicators rely on road users getting within specific temporal and spatial proximity from each other and therefore assume that proximity is a surrogate for conflict severity. However, this assumption may not be valid in many driving environments where close interActions between road users are common. The objective of this paper is to investigate the applicability of time proximity conflict indicators for evaluating pedestrian safety in less-organized traffic environments with a high mix of road users. Several alternative behavioural conflict indicators based on detecting pedestrian Evasive Actions are recommended to better measure traffic conflicts in such traffic environments. These indicators represent variations in the spatio-temporal gait parameters (step length, step frequency and walk ratio) immediately before the conflict point. A highly congested shared intersection in Shanghai, China, with frequent pedestrian conflicts is used as a case study. Traffic conflicts are analysed with the use of automated video-based analysis techniques. The results showed that Evasive Action-based indicators have higher potential to identify pedestrian conflicts and measure their severity in high mix less organized traffic environments than time proximity measures such as time-to-collision and post-encroachment time. Copyright © 2016 John Wiley & Sons, Ltd.
Mohamed H Zaki - One of the best experts on this subject based on the ideXlab platform.
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exploring Evasive Action based indicators for ptw conflicts in shared traffic facility environments
Journal of Transportation Engineering Part A: Systems, 2018Co-Authors: Yanyong Guo, Tarek Sayed, Mohamed H ZakiAbstract:AbstractSurrogate safety measures such as traffic conflicts are gaining more and more attention for traffic safety analysis. The traffic conflict technique evaluates the frequency and severity of t...
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Exploring Evasive Action–Based Indicators for PTW Conflicts in Shared Traffic Facility Environments
Journal of Transportation Engineering Part A: Systems, 2018Co-Authors: Yanyong Guo, Tarek Sayed, Mohamed H ZakiAbstract:AbstractSurrogate safety measures such as traffic conflicts are gaining more and more attention for traffic safety analysis. The traffic conflict technique evaluates the frequency and severity of t...
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use of drivers jerk profiles in computer vision based traffic safety evaluations
Transportation Research Record, 2014Co-Authors: Mohamed H Zaki, Tarek Sayed, Khaled ShaabanAbstract:A traffic conflict is usually composed of a chain of events in which at least one of the involved road users performs some sort of Evasive Action to avoid a collision. An Evasive Action usually involves powerful braking, which leads to sudden, negative change in acceleration (deceleration). The temporal dynamics (variation over time) of the acceleration of a vehicle is represented by the jerk profile. More formally, jerk is the derivative of the acceleration. In the case of an Evasive Action by braking, the jerk profile is characterized by strong, negative values. This study examined two issues in the quest to understand the benefits of Evasive Action analysis. The first issue was whether jerk profiles can be used to identify critical traffic events (conflicts). The second issue addressed the validity of the assumption that the deceleration profile is inadequate as a stand-alone measure for conflict identification. Automated video analysis was used to collect traffic data and analysis was applied on two d...
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Use of Drivers’ Jerk Profiles in Computer Vision–Based Traffic Safety Evaluations:
Transportation Research Record, 2014Co-Authors: Mohamed H Zaki, Tarek Sayed, Khaled ShaabanAbstract:A traffic conflict is usually composed of a chain of events in which at least one of the involved road users performs some sort of Evasive Action to avoid a collision. An Evasive Action usually involves powerful braking, which leads to sudden, negative change in acceleration (deceleration). The temporal dynamics (variation over time) of the acceleration of a vehicle is represented by the jerk profile. More formally, jerk is the derivative of the acceleration. In the case of an Evasive Action by braking, the jerk profile is characterized by strong, negative values. This study examined two issues in the quest to understand the benefits of Evasive Action analysis. The first issue was whether jerk profiles can be used to identify critical traffic events (conflicts). The second issue addressed the validity of the assumption that the deceleration profile is inadequate as a stand-alone measure for conflict identification. Automated video analysis was used to collect traffic data and analysis was applied on two d...
Khaled Shaaban - One of the best experts on this subject based on the ideXlab platform.
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Comparison of Time-Proximity and Evasive Action Conflict Measures: Case Studies from Five Cities:
Transportation Research Record: Journal of the Transportation Research Board, 2017Co-Authors: Ahmed Tageldin, Tarek Sayed, Khaled ShaabanAbstract:Interest has grown in using traffic conflicts for studying safety from a broader perspective than relying only on collision data. Traffic conflict analysis is typically performed through the calculation of traditional conflict severity measures such as time-to-collision and postencroachment time. These measures rely on road users getting within specific temporal and spatial proximity from each other and therefore assume that proximity is the surrogate for severity. However, this assumption may not be valid in some driving environments where close interActions between road users are common and sudden Evasive Actions are frequently used to avoid collisions. It is suggested that Evasive Action–based conflict indicators can assess the analysis in some less-organized traffic environments. This study focused on the severity evaluation of pedestrian conflicts. Pedestrian Evasive Actions were reflected mainly in variations of spatiotemporal gait parameters (step frequency and step length). The objective was to co...
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time proximity measures vs Evasive Action measures for pedestrian conflicts in different traffic environments case studies from four major cities
17th International Conference Road Safety On Five Continents (RS5C 2016) Rio de Janeiro Brazil 17-19 May 2016, 2016Co-Authors: Ahmed Tageldin, Tarek Sayed, Khaled ShaabanAbstract:There has been a growing interest in using traffic conflicts for studying safety from a broader perspective than relying only on collision data. The analysis of traffic conflicts is typically perfo ...
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use of drivers jerk profiles in computer vision based traffic safety evaluations
Transportation Research Record, 2014Co-Authors: Mohamed H Zaki, Tarek Sayed, Khaled ShaabanAbstract:A traffic conflict is usually composed of a chain of events in which at least one of the involved road users performs some sort of Evasive Action to avoid a collision. An Evasive Action usually involves powerful braking, which leads to sudden, negative change in acceleration (deceleration). The temporal dynamics (variation over time) of the acceleration of a vehicle is represented by the jerk profile. More formally, jerk is the derivative of the acceleration. In the case of an Evasive Action by braking, the jerk profile is characterized by strong, negative values. This study examined two issues in the quest to understand the benefits of Evasive Action analysis. The first issue was whether jerk profiles can be used to identify critical traffic events (conflicts). The second issue addressed the validity of the assumption that the deceleration profile is inadequate as a stand-alone measure for conflict identification. Automated video analysis was used to collect traffic data and analysis was applied on two d...
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Use of Drivers’ Jerk Profiles in Computer Vision–Based Traffic Safety Evaluations:
Transportation Research Record, 2014Co-Authors: Mohamed H Zaki, Tarek Sayed, Khaled ShaabanAbstract:A traffic conflict is usually composed of a chain of events in which at least one of the involved road users performs some sort of Evasive Action to avoid a collision. An Evasive Action usually involves powerful braking, which leads to sudden, negative change in acceleration (deceleration). The temporal dynamics (variation over time) of the acceleration of a vehicle is represented by the jerk profile. More formally, jerk is the derivative of the acceleration. In the case of an Evasive Action by braking, the jerk profile is characterized by strong, negative values. This study examined two issues in the quest to understand the benefits of Evasive Action analysis. The first issue was whether jerk profiles can be used to identify critical traffic events (conflicts). The second issue addressed the validity of the assumption that the deceleration profile is inadequate as a stand-alone measure for conflict identification. Automated video analysis was used to collect traffic data and analysis was applied on two d...
Ahmed Tageldin - One of the best experts on this subject based on the ideXlab platform.
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Comparison of Time-Proximity and Evasive Action Conflict Measures: Case Studies from Five Cities:
Transportation Research Record: Journal of the Transportation Research Board, 2017Co-Authors: Ahmed Tageldin, Tarek Sayed, Khaled ShaabanAbstract:Interest has grown in using traffic conflicts for studying safety from a broader perspective than relying only on collision data. Traffic conflict analysis is typically performed through the calculation of traditional conflict severity measures such as time-to-collision and postencroachment time. These measures rely on road users getting within specific temporal and spatial proximity from each other and therefore assume that proximity is the surrogate for severity. However, this assumption may not be valid in some driving environments where close interActions between road users are common and sudden Evasive Actions are frequently used to avoid collisions. It is suggested that Evasive Action–based conflict indicators can assess the analysis in some less-organized traffic environments. This study focused on the severity evaluation of pedestrian conflicts. Pedestrian Evasive Actions were reflected mainly in variations of spatiotemporal gait parameters (step frequency and step length). The objective was to co...
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Developing Evasive Action‐based indicators for identifying pedestrian conflicts in less organized traffic environments
Journal of Advanced Transportation, 2016Co-Authors: Ahmed Tageldin, Tarek SayedAbstract:Summary There has been a growing interest in using surrogate safety measures such as traffic conflicts to analyse road safety from a broader perspective than collision data alone. This growing interest has been aided by recent advances in automated video-based traffic conflict analysis. The automation enables accurate calculation of various conflict indicators such as time-to-collision and post-encroachment time. These indicators rely on road users getting within specific temporal and spatial proximity from each other and therefore assume that proximity is a surrogate for conflict severity. However, this assumption may not be valid in many driving environments where close interActions between road users are common. The objective of this paper is to investigate the applicability of time proximity conflict indicators for evaluating pedestrian safety in less-organized traffic environments with a high mix of road users. Several alternative behavioural conflict indicators based on detecting pedestrian Evasive Actions are recommended to better measure traffic conflicts in such traffic environments. These indicators represent variations in the spatio-temporal gait parameters (step length, step frequency and walk ratio) immediately before the conflict point. A highly congested shared intersection in Shanghai, China, with frequent pedestrian conflicts is used as a case study. Traffic conflicts are analysed with the use of automated video-based analysis techniques. The results showed that Evasive Action-based indicators have higher potential to identify pedestrian conflicts and measure their severity in high mix less organized traffic environments than time proximity measures such as time-to-collision and post-encroachment time. Copyright © 2016 John Wiley & Sons, Ltd.
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developing Evasive Action based indicators for identifying pedestrian conflicts in less organized traffic environments
Journal of Advanced Transportation, 2016Co-Authors: Ahmed Tageldin, Tarek SayedAbstract:Summary There has been a growing interest in using surrogate safety measures such as traffic conflicts to analyse road safety from a broader perspective than collision data alone. This growing interest has been aided by recent advances in automated video-based traffic conflict analysis. The automation enables accurate calculation of various conflict indicators such as time-to-collision and post-encroachment time. These indicators rely on road users getting within specific temporal and spatial proximity from each other and therefore assume that proximity is a surrogate for conflict severity. However, this assumption may not be valid in many driving environments where close interActions between road users are common. The objective of this paper is to investigate the applicability of time proximity conflict indicators for evaluating pedestrian safety in less-organized traffic environments with a high mix of road users. Several alternative behavioural conflict indicators based on detecting pedestrian Evasive Actions are recommended to better measure traffic conflicts in such traffic environments. These indicators represent variations in the spatio-temporal gait parameters (step length, step frequency and walk ratio) immediately before the conflict point. A highly congested shared intersection in Shanghai, China, with frequent pedestrian conflicts is used as a case study. Traffic conflicts are analysed with the use of automated video-based analysis techniques. The results showed that Evasive Action-based indicators have higher potential to identify pedestrian conflicts and measure their severity in high mix less organized traffic environments than time proximity measures such as time-to-collision and post-encroachment time. Copyright © 2016 John Wiley & Sons, Ltd.
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time proximity measures vs Evasive Action measures for pedestrian conflicts in different traffic environments case studies from four major cities
17th International Conference Road Safety On Five Continents (RS5C 2016) Rio de Janeiro Brazil 17-19 May 2016, 2016Co-Authors: Ahmed Tageldin, Tarek Sayed, Khaled ShaabanAbstract:There has been a growing interest in using traffic conflicts for studying safety from a broader perspective than relying only on collision data. The analysis of traffic conflicts is typically perfo ...
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Can Time Proximity Measures Be Used as Safety Indicators in All Driving Cultures? A Case Study of Motorcycle Safety in China
2015Co-Authors: Ahmed Tageldin, Tarek Sayed, Xuesong WangAbstract:1 Limitations associated with traditional collision-based safety analysis techniques led to a growing interest 2 in the use of surrogate safety measures such as the traffic conflict technique. This interest has been 3 facilitated by advances in automated video-based data collection methods that are helping to overcome 4 the reliability issues associated with manual traffic conflict data collection. Various objective conflict 5 indicators are available to measure the severity of traffic events which measure various spatial and 6 temporal aspects of user proximity. These time proximity conflict measures assume that proximity is a 7 surrogate for conflict severity. However, this assumption may not be valid in many driving environments. 8 The objective of this paper is to investigate whether time-proximity conflict measures can be a good 9 indicator of safety in less organized traffic environments with a high mix of road users. A case study of 10 motorcycle conflicts in a highly congested shared intersection in Shanghai, China is used as a case study. 11 Traffic conflicts are analysed with the use of automated video-based analysis techniques. Several traffic 12 conflict indicators based on detecting Evasive Actions such as deceleration, jerk, and yaw-rate are 13 recommended to better measure traffic conflicts in such traffic environments. The results showed that 14 Evasive Action based indicators have higher potential to identify motorcycle conflicts in high mix, less 15 organized traffic environments than time proximity measures such as the time to collision. 16
Gordon B. Bauer - One of the best experts on this subject based on the ideXlab platform.
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Behavioral lateralization in the Florida manatee (Trichechus manatus latirostris)
International Journal of Comparative Psychology, 2016Co-Authors: Kara Tyler-julian, Kate M Chapman, Candice Frances, Gordon B. BauerAbstract:Author(s): Tyler-Julian, Kara; Chapman, Kate M; Frances, Candice; Bauer, Gordon B | Abstract: We examined side preferences in the Florida manatee (Trichechus manatus latirostris) through observations of limb use (right and left flipper) in 123 wild and 16 captive individuals. We also analyzed archival data on wild manatees to develop an index of boat-caused body scars to determine lateralization of Evasive Action. Wild and captive manatees displayed flipper lateralization at the individual, but not the population level for several behaviors including substrate touches, sculling, and feeding. In contrast, manatees were lateralized at the population level for boat-scar biases with more manatees showing a left scar bias (45%) versus right (34%) or dorsal (21%).