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Jiang Yu Zheng - One of the best experts on this subject based on the ideXlab platform.

  • vehicle Bicyclist dynamic position extracted from naturalistic driving videos
    IEEE Transactions on Intelligent Transportation Systems, 2017
    Co-Authors: Chao Liu, Lauren Christopher, Ryo Fujishiro, Jiang Yu Zheng
    Abstract:

    Pre-collision systems (PCS) are designed to warn a driver or brake automatically to help avoid or mitigate accidents, protecting vulnerable road users such as pedestrians and Bicyclists. A PCS system needs to understand both normal and abnormal behavior of the vulnerable users in order to have high true-positive and low false-positive detection of PCS events. In this paper, the normal Bicyclist behavior is analyzed based on naturalistic driving data. These data can inform the PCS design and lead to proper testing and evaluation of PCS systems. This paper focuses on the following attributes of normal Bicyclist behavior: time to collision, lateral position, and bicycle speed. The behavior was analyzed using the Transportation Active Safety Institute naturalistic driving data from 110 cars. This paper presents new analysis gleaned from these data, plotted in 2-D graphical form, showing heat maps of common bicycle positions and trajectories of the dynamic vehicle–bicycle interactions.

  • Bicyclist detection in large scale naturalistic driving video
    International Conference on Intelligent Transportation Systems, 2014
    Co-Authors: Kai Yang, Chao Liu, Jiang Yu Zheng, Lauren Christopher, Yaobin Chen
    Abstract:

    Monocular based Bicyclist detection in naturalistic driving video is a very challenging problem due to the high variance of the Bicyclist appearance and complex background of naturalistic driving environment. In this paper, we propose a two-stage multi-modal Bicyclist detection scheme to efficiently detect Bicyclists with varied poses for further behavior analysis. A new motion based region of interest (ROI) detection is first applied to the entire video to refine the region for sliding-window detection. Then an efficient integral feature based detector is applied to quickly filter out the negative windows. Finally, the remaining candidate windows are encoded and tested by three pre-learned pose-specific detectors. The experimental results on our TASI 110 car naturalistic driving dataset show the effectiveness and efficiency of the proposed method. The proposed method outperforms the traditional

Zheng Luo - One of the best experts on this subject based on the ideXlab platform.

  • Pedestrian and Bicyclist Violations at Highway–Rail Grade Crossings
    Transportation Research Record, 2011
    Co-Authors: Aemal J. Khattak, Zheng Luo
    Abstract:

    Each year numerous pedestrian and Bicyclist crashes involving high injury levels are reported at highway-rail grade crossings (HRGCs) across the United States. Such crashes are invariably the result of errors on the part of the pedestrians and Bicyclists. The focus of this paper is to investigate pedestrian and Bicyclist violations at a dual-quadrant gated HRGC and to report on four types of gate violations, including factors associated with those violations. For both pedestrians and Bicyclists, the violations studied were (a) passing under descending gates, (b) passing around fully lowered gates, (c) passing under ascending gates, and (d) passing around fully lowered gates between successive trains. Data on pedestrian and Bicyclist violations were collected at a grade crossing in Nebraska through the use of video surveillance. Analysis indicated that there were no significant differences in the mean frequencies of pedestrian and Bicyclist violations at HRGCs. When data for pedestrians and Bicyclists were...

  • pedestrian and Bicyclist violations at highway rail grade crossings
    Transportation Research Record, 2011
    Co-Authors: Aemal J. Khattak, Zheng Luo
    Abstract:

    Each year numerous pedestrian and Bicyclist crashes involving high injury levels are reported at highway-rail grade crossings (HRGCs) across the United States. Such crashes are invariably the result of errors on the part of the pedestrians and Bicyclists. The focus of this paper is to investigate pedestrian and Bicyclist violations at a dual-quadrant gated HRGC and to report on four types of gate violations, including factors associated with those violations. For both pedestrians and Bicyclists, the violations studied were (a) passing under descending gates, (b) passing around fully lowered gates, (c) passing under ascending gates, and (d) passing around fully lowered gates between successive trains. Data on pedestrian and Bicyclist violations were collected at a grade crossing in Nebraska through the use of video surveillance. Analysis indicated that there were no significant differences in the mean frequencies of pedestrian and Bicyclist violations at HRGCs. When data for pedestrians and Bicyclists were...

Ron Buliung - One of the best experts on this subject based on the ideXlab platform.

  • the built environment and active transportation safety in children and youth a study protocol
    BMC Public Health, 2019
    Co-Authors: Brent Edward Hagel, Meghan Winters, Alison Macpherson, Andrew W Howard, Pamela Fuselli, Mariesoleil Cloutier, Sarah A Richmond, Linda Rothman, Kathy Belton, Ron Buliung
    Abstract:

    Active transportation, such as walking and biking, is a healthy way for children to explore their environment and develop independence. However, children can be injured while walking and biking. Many cities make changes to the built environment (e.g., traffic calming features, separated bike lanes) to keep people safe. There is some research on how effective these changes are in preventing adult pedestrians and Bicyclists from getting hurt, but very little research has been done to show how safe various environments are for children and youth. Our research program will study how features of the built environment affect whether children travel (e.g., to school) using active modes, and whether certain features increase or decrease their likelihood of injury. First, we will use a cross-sectional study design to estimate associations between objectively measured built environment and objectively measured active transportation to school among child elementary students. We will examine the associations between objectively measured built environment and child and youth pedestrian-motor vehicle collisions (MVCs) and Bicyclist-MVCs. We will also use these data to determine the space-time distribution of pedestrian-MVCs and Bicyclist-MVCs. Second, we will use a case-crossover design to compare the built environment characteristics of the site where child and youth Bicyclists sustain emergency department reported injuries and two randomly selected sites (control sites) along the Bicyclist’s route before the injury occurred. Third, to identify implementation strategies for built environment change at the municipal level to encourage active transportation we will conduct: 1) an environmental scan, 2) key informant interviews, 3) focus groups, and 4) a national survey to identify facilitators and barriers for implementing built environment change in municipalities. Finally, we will develop a built environment implementation toolkit to promote active transportation and prevent child pedestrian and Bicyclist injuries. This program of research will identify the built environment associated with active transportation safety and form an evidence base from which municipalities can draw information to support change. Our team’s national scope will be invaluable in providing information regarding the variability in built environment characteristics and is vital to producing evidence-based recommendations that will increase safe active transportation.

Randy B Machemehl - One of the best experts on this subject based on the ideXlab platform.

  • Effects of Bicycle Boxes on Bicyclist and Motorist Behavior at Intersections in Austin, Texas
    Journal of Transportation Engineering, 2013
    Co-Authors: Jeff Loskorn, Alison Fayre Mills, John F. Brady, Jennifer Duthie, Randy B Machemehl
    Abstract:

    AbstractProvision of bicycle facilities at intersections is often inadequate and can lead to unsafe interactions between motorists and Bicyclists. The bicycle box is a tool intended to improve the predictability of Bicyclist stopping position at an intersection by allowing Bicyclists utilizing a bicycle lane to position themselves in front of motorists during a red phase. The bicycle box in this application is meant to reduce the possibility of a right-hook collision, where a right-turning motorist collides with a through-moving Bicyclist departing the intersection. The primary goal of this study was to determine what effect, if any, bicycle boxes have on Bicyclist and motorist behavior. In 2009, 950 Bicyclists were observed at two sites in three phases: existing conditions, after bicycle box markings were installed, and after a green colored pavement marking was added to the bicycle box and approaching bicycle lane. The predictability of Bicyclists’ behavior improved based on the increased percentage of ...

  • Effects of Shared Lane Markings on Bicyclist and Motorist Behavior
    Ite Journal-institute of Transportation Engineers, 2011
    Co-Authors: John F. Brady, Jeff Loskorn, Alison Fayre Mills, Jennifer Duthie, Randy B Machemehl
    Abstract:

    The shared lane marking, also known as a “sharrow,” is a new pavement marking that is placed in a lane shared by drivers and Bicyclists. The marking is designed to encourage Bicyclists to ride at the safest position and to alert motorists to the possible presence of Bicyclists. This study evaluates the impact of sharrows on Bicyclist and motorist safety at three sites in Austin, Texas. Before-and-after data sets for each site were compared to determine whether safer conditions existed after the installation. Safe motorist behavior was defined by two factors: motorists did not encroach on adjacent lanes when passing, and motorists made complete lane changes when passing. Safe Bicyclist behavior was defined by three factors: the Bicyclists rode at the lane position indicated by the sharrow; the Bicyclist did not ride outside of the lane; and the Bicyclist did not ride alongside queues of stopped vehicles. The findings indicate that shared lane markings improved the safety for both Bicyclists and motorists. After the installation of the shared lane markings, Bicyclists rode further from the curb and closer toward the center of the lane. Motorists were shown to be less likely to pass, more likely to change lanes when passing, and were less likely to encroach on the adjacent lane when passing. The authors recommend that shared lane markings be considered for multilane facilities where the roadway cannot be reasonably adjusted to accommodate a dedicated bicycle lane. Shared lane markings should be placed in the center of the usable lanes unless it is possible for Bicyclists and motorists to share the lane safely side-by-side.

  • Effects of Bicycle Boxes on Bicyclist and Motorist Behavior at Intersections in Austin, Texas
    2011
    Co-Authors: Jeff Loskorn, Alison Fayre Mills, John F. Brady, Jennifer Duthie, Randy B Machemehl
    Abstract:

    The provision of bicycle facilities at intersections is often inadequate and can lead to unsafe interactions between motorists and Bicyclists. The bicycle box is a tool intended to improve the predictability of Bicyclist stopping position at an intersection by allowing Bicyclists utilizing a bicycle lane to position themselves in front of motorists during a red phase. The bicycle box in this application is meant to reduce the possibility of a right-hook collision, where a right-turning motorist collides with a through-moving Bicyclist as they depart the intersection. The primary goal of this study was to determine what effect, if any, bicycle boxes have on Bicyclist and motorist behavior. Data was collected at two sites under three conditions: no bicycle box, after bicycle box markings were installed, and after chartreuse (or strong yellow-green) color was added to the bicycle box and approaching bicycle lane. Bicyclists showed significant improvement in predictability based on the increased percentage of Bicyclists who used the bicycle lane to approach the intersection, depart the intersection before motorists, and stop in the colored area of the bicycle box. Approximately 20% to 26% of Bicyclists stopped in the bicycle box area after installation of the bicycle box markings. The addition of the chartreuse color led to significant improvements in Bicyclist behavior, but at a considerably higher cost. Motorist encroachment on the bicycle box was common at both sites as well as illegal right turns on red at one site. No bicycle-motorist collisions were observed during any phase of the study.

Chao Liu - One of the best experts on this subject based on the ideXlab platform.

  • vehicle Bicyclist dynamic position extracted from naturalistic driving videos
    IEEE Transactions on Intelligent Transportation Systems, 2017
    Co-Authors: Chao Liu, Lauren Christopher, Ryo Fujishiro, Jiang Yu Zheng
    Abstract:

    Pre-collision systems (PCS) are designed to warn a driver or brake automatically to help avoid or mitigate accidents, protecting vulnerable road users such as pedestrians and Bicyclists. A PCS system needs to understand both normal and abnormal behavior of the vulnerable users in order to have high true-positive and low false-positive detection of PCS events. In this paper, the normal Bicyclist behavior is analyzed based on naturalistic driving data. These data can inform the PCS design and lead to proper testing and evaluation of PCS systems. This paper focuses on the following attributes of normal Bicyclist behavior: time to collision, lateral position, and bicycle speed. The behavior was analyzed using the Transportation Active Safety Institute naturalistic driving data from 110 cars. This paper presents new analysis gleaned from these data, plotted in 2-D graphical form, showing heat maps of common bicycle positions and trajectories of the dynamic vehicle–bicycle interactions.

  • Bicyclist detection in large scale naturalistic driving video
    International Conference on Intelligent Transportation Systems, 2014
    Co-Authors: Kai Yang, Chao Liu, Jiang Yu Zheng, Lauren Christopher, Yaobin Chen
    Abstract:

    Monocular based Bicyclist detection in naturalistic driving video is a very challenging problem due to the high variance of the Bicyclist appearance and complex background of naturalistic driving environment. In this paper, we propose a two-stage multi-modal Bicyclist detection scheme to efficiently detect Bicyclists with varied poses for further behavior analysis. A new motion based region of interest (ROI) detection is first applied to the entire video to refine the region for sliding-window detection. Then an efficient integral feature based detector is applied to quickly filter out the negative windows. Finally, the remaining candidate windows are encoded and tested by three pre-learned pose-specific detectors. The experimental results on our TASI 110 car naturalistic driving dataset show the effectiveness and efficiency of the proposed method. The proposed method outperforms the traditional