Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Design Example: Analyzing Capacity Contours for Flood Risk Assessment01:17

Design Example: Analyzing Capacity Contours for Flood Risk Assessment

100
Flood risk assessment involves careful planning and analysis to ensure the safety of communities near water retention structures. Capacity contours are a vital tool in this process, as they illustrate the potential spread of water at specific levels in a given area. In the context of building a bund across a small valley, these contours play a critical role in evaluating the safety of nearby residential areas.In this example, the bund is intended to store stormwater in the valley. The engineers...
100
Design Example: Calculating Safe Diameter for Wind-Exposed Disc01:17

Design Example: Calculating Safe Diameter for Wind-Exposed Disc

177
Assessing safety in wind-exposed installations is crucial to preventing potential failures. This example explores the calculation and design adjustments needed to mount a circular disc on a building facade, where wind forces are a primary concern. A 4-meter diameter disc was initially designed as an aesthetic feature facing winds at a velocity of 25 meters per second, with an air density of 1.25 kilograms per cubic meter. Given these conditions, the drag force on the disc was determined using...
177
Relative Risk01:12

Relative Risk

340
Relative risk (RR) is a statistical measure commonly used in epidemiology to compare the likelihood of a particular event occurring between two groups. This metric is important for evaluating the relationship between exposure to a specific risk factor and the probability of a particular outcome. It plays a crucial role in medical research, public health studies, and risk assessment. Relative risk quantifies how much more (or less) likely an event is to occur in an exposed group compared to an...
340
Determination of Expected Frequency01:08

Determination of Expected Frequency

2.2K
Suppose one wants to test independence between the two variables of a contingency table. The values in the table constitute the observed frequencies of the dataset. But how does one determine the expected frequency of the dataset? One of the important assumptions is that the two variables are independent, which means the variables do not influence each other. For independent variables, the statistical probability of any event involving both variables is calculated by multiplying the individual...
2.2K
Parametric Survival Analysis: Weibull and Exponential Methods01:14

Parametric Survival Analysis: Weibull and Exponential Methods

600
Parametric survival analysis models survival data by assuming a specific probability distribution for the time until an event occurs. The Weibull and exponential distributions are two of the most commonly used methods in this context, due to their versatility and relatively straightforward application.
Weibull Distribution
The Weibull distribution is a flexible model used in parametric survival analysis. It can handle both increasing and decreasing hazard rates, depending on its shape parameter...
600
Unusual Results01:16

Unusual Results

3.3K
Unusual results are those that have a very low chance of occurring. Unusual results can be identified using probabilities and the range rule of thumb. In problems involving probability, unusual results can be observed in 2 instances – an unusually high number of successes or an unusually low number of successes.
According to the range rule of thumb, any value above or below two standard deviations, 2σ  from the mean, μ  is considered unusual.
Maximum unusual value =...
3.3K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

The interaction between chronic hepatitis B (CHB) and Metabolic dysfunction-associated steatotic liver disease (MASLD) in a diverse central London population.

medRxiv : the preprint server for health sciences·2026
Same author

Viral hepatitis and liver disease in the Mongolian community in London ('MoLo'): A mixed methods study protocol to investigate the epidemiology and burden of disease to inform clinical and public health interventions.

Wellcome open research·2026
Same author

Preserved CD4 <sup>+</sup> T cell helper function and coordinated antiviral immunity in people with HBV/HIV co-infection on long-term therapy.

bioRxiv : the preprint server for biology·2026
Same author

Prevalence of elder abuse among community-dwelling older adults in South Asia: a systematic review and meta-analysis.

BMC public health·2026
Same author

Subcutaneous drug delivery of high concentration antibody products - part 2: formulation, device options, and clinical bridging strategies for patient-centric commercial presentations.

mAbs·2026
Same author

A systematic review of qualitative research on HIV and food insecurity in high-income countries.

AIDS (London, England)·2026

Related Experiment Video

Updated: Sep 9, 2025

Evaluation of an Exclusive Spur Dike U-Turn Design with Radar-Collected Data and Simulation
11:41

Evaluation of an Exclusive Spur Dike U-Turn Design with Radar-Collected Data and Simulation

Published on: February 1, 2020

20.5K

A copula-based multivariate extreme value framework for roundabout safety evaluation under mixed traffic.

Abhijnan Maji1, Indrajit Ghosh1

  • 1Department of Civil Engineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India.

Accident; Analysis and Prevention
|August 28, 2025
PubMed
Summary
This summary is machine-generated.

This study introduces a new framework to improve roundabout safety in developing countries by analyzing traffic conflicts using drone footage and advanced modeling. It identifies high-risk areas and conflict types to guide targeted safety interventions.

Keywords:
Conflict SeverityExtreme Value Theory (EVT)Heterogeneous trafficMultivariate CopulaTraffic Conflict Technique (TCT)UAV trajectory data

More Related Videos

Evaluating the Effect of Roadside Parking on a Dual-Direction Urban Street
14:55

Evaluating the Effect of Roadside Parking on a Dual-Direction Urban Street

Published on: January 20, 2023

3.4K
An R-Based Landscape Validation of a Competing Risk Model
05:37

An R-Based Landscape Validation of a Competing Risk Model

Published on: September 16, 2022

2.2K

Related Experiment Videos

Last Updated: Sep 9, 2025

Evaluation of an Exclusive Spur Dike U-Turn Design with Radar-Collected Data and Simulation
11:41

Evaluation of an Exclusive Spur Dike U-Turn Design with Radar-Collected Data and Simulation

Published on: February 1, 2020

20.5K
Evaluating the Effect of Roadside Parking on a Dual-Direction Urban Street
14:55

Evaluating the Effect of Roadside Parking on a Dual-Direction Urban Street

Published on: January 20, 2023

3.4K
An R-Based Landscape Validation of a Competing Risk Model
05:37

An R-Based Landscape Validation of a Competing Risk Model

Published on: September 16, 2022

2.2K

Area of Science:

  • Transportation Engineering
  • Traffic Safety Analysis
  • Data-Driven Modeling

Background:

  • Roundabouts in low- and middle-income countries face unique safety challenges due to non-lane-based traffic and mixed traffic conditions.
  • Traditional crash-based analyses are limited in identifying proactive safety measures for these complex environments.

Purpose of the Study:

  • To develop and validate a data-driven framework for proactively identifying and classifying safety-critical conflict events at unsignalized roundabouts.
  • To integrate high-resolution video analysis, advanced statistical modeling, and machine learning for a comprehensive safety assessment.

Main Methods:

  • Utilized drone-recorded video to extract vehicle trajectories and compute surrogate safety measures (SSMs) like Time-to-Collision (TTC) and Post-Encroachment Time (PET) using the Surrogate Safety Assessment Model (SSAM).
  • Applied multivariate Extreme Value Theory (EVT)-Peak-Over-Threshold (POT) modeling with a Gumbel-Hougaard copula to analyze joint exceedances of SSMs and establish context-specific thresholds.
  • Employed probabilistic clustering (Gaussian Mixture Model) for spatial conflict mapping and latent profile analysis to stratify conflicts by severity.

Main Results:

  • Identified key conflict types: lane-change interactions (43%), rear-end (38%), and crossing (19%), with specific hotspots at approach legs, weaving zones, and pedestrian crossings.
  • Quantified conflict severity into five levels, ranging from minor (29.7%) to critical (7.6%), providing a basis for prioritized safety interventions.
  • The EVT-POT model with copula effectively captured tail dependencies among SSMs, demonstrating its suitability for joint risk assessment.

Conclusions:

  • The developed framework offers a scalable and proactive approach to enhance roundabout safety in diverse traffic conditions.
  • It enables practitioners to pinpoint high-risk areas and implement targeted safety countermeasures, moving beyond reactive, crash-based methods.
  • This research provides valuable insights for improving the design and operation of roundabouts, particularly in resource-limited settings.