Hanseon Cho

Development of an Automatic Traffic Conflict Detection System Based on Image Tracking Technology

Increasing reliance on surveillance has emphasized the need for better vehicle detection, such as with wide-area detectors. Traffic information from vehicle trajectories can be especially useful because it measures spatial information rather than single-point information. Additional information from vehicle trajectories could lead to improved incident detection, both by identifying stopped vehicles within the cameras field of view and by tracking detailed vehicle movement trajectories. In this research, a vehicle image processing system was developed by using a vehicle tracking algorithm, and a traffic conflict technology was applied to the tracking system. To overcome the limitations of the existing traffic conflict technology, this study developed a traffic conflict technology that considers the severity of different types of conflict. To apply this method, video images were collected from intersections at Jungja and Naejung in Sungnam City, South Korea. The image processing approach adopted in this research was based on the use of a single camera installed at the corner of a street to detect vehicles approaching an intersection from all directions, and they were analyzed with the traffic information extracted from the image tracking system. To verify the tracking system, three categories were tested: traffic volume and speed accuracy, vehicle trajectory tracking, and traffic conflict.

Safety Impacts of Intervehicle Warning Information Systems for Moving Hazards in Connected Vehicle Environments

Driver inattentiveness is one of the critical factors that contribute to vehicle crashes. The intervehicle safety warning information system (ISWS) is a technology to enhance driver attentiveness by providing warning messages about upcoming hazards under the connected vehicle environments. A novel feature of the proposed ISWS is its capability to detect hazardous driving events, which are defined as moving hazards with a high potential to cause crashes. The study presented in this paper evaluated the potential effectiveness of the ISWS to reduce crashes and to mitigate traffic congestion. The study included a field experiment that documented actual vehicle maneuvering patterns of accelerations and lane changes, which were used to enhance the realism of simulation evaluations. Probe vehicles equipped with customized onboard units, which consisted of a GPS device, accelerometer, and gyro sensor, were used. A microscopic simulator, VISSIM, was used to simulate a drivers responsive behavior after warning messages were delivered. A surrogate safety assessment model was used to derive surrogate safety measures to evaluate the effectiveness of ISWS in terms of traffic safety. The results showed a reduced number of rear-end conflicts when the ISWSs market penetration rate (MPR) and the congestion level of the traffic conditions increased. The reduced number of rear-end conflicts was approximately 84.3%, with a 100% MPR under Level of Service D traffic conditions. Analysis of the standard deviation of speed showed that a reduction of 39.9% was achieved. The outcomes of this study could be valuable to derive smarter operational strategies for ISWS.

Investigating optimal aggregation interval sizes of loop detector data for freeway travel-time estimation and prediction

With recent increases in the deployment of intelligent transportation system (ITS) technologies, traffic management centers have the ability to obtain and archive large amounts of data regarding th...

Modeling Signalized Intersections Near Highway-Railroad Grade Crossings: Sensitivity Analyses of Key Design Parameters

Many roadway intersections throughout North America are located near highway-railroad grade crossings (IHRGCs). Numerous safety, operational, and legal challenges are associated with IHRGCs; and these become significantly more complex when traffic signals are present. Because of the complexity of traffic operations at IHRGCs, existing macroscopic analysis approaches are not suitable for in-depth analyses. Consequently, a more detailed methodology for the analysis of intersections with traffic signals located near IHRGCs was developed. The approach is microsimulation based and relies on hardware-in-the-loop architecture to model the traffic signal controller. To demonstrate the methodology, sensitivity analyses of key design parameters were undertaken, and their impacts on safety and delay were analyzed. Specifically, (a) the maximum train speed and the corresponding length of the detector, (b) the effect of the pedestrian volume, and (c) the effect of the addition of an additional upstream train detector ...

Modeling Signalized Intersections near Highway–Railroad Grade Crossings

Many roadway intersections throughout North America are located near highway–railroad grade crossings (IHRGCs). Numerous safety, operational, and legal challenges are associated with IHRGCs; and these become significantly more complex when traffic signals are present. Because of the complexity of traffic operations at IHRGCs, existing macroscopic analysis approaches are not suitable for in-depth analyses. Consequently, a more detailed methodology for the analysis of intersections with traffic signals located near IHRGCs was developed. The approach is microsimulation based and relies on hardware-in-the-loop architecture to model the traffic signal controller. To demonstrate the methodology, sensitivity analyses of key design parameters were undertaken, and their impacts on safety and delay were analyzed. Specifically, (a) the maximum train speed and the corresponding length of the detector, (b) the effect of the pedestrian volume, and (c) the effect of the addition of an additional upstream train detector were examined in terms of safety and delay at the IHRGC. The methodology was tested with empirical data from a test bed in College Station, Texas. It was found that the manner in which the maximum train speed was calculated could have a statistically significant effect on delay and a detrimental effect on safety. It was also shown that the addition of an additional upstream detector could reduce delay and increase safety.