Analysis of Exit Visibility and Information Asymmetry Impacts in Crowd Evacuation

Analysis of Exit Visibility and Information Asymmetry Impacts in Crowd Evacuation

Topic Description
In emergency evacuation scenarios, the physical visibility of exits (e.g., presence of obstructions, distance) and the completeness of information available to evacuees (e.g., knowledge of all exit locations) jointly influence evacuation efficiency. Information asymmetry refers to the situation where some individuals possess more exit information (e.g., those familiar with the venue), while others may rely on limited visibility or following behaviors. This topic requires analyzing how such visibility and information differences affect crowd evacuation dynamics and exploring improvement strategies.

Problem-Solving Process

  1. Problem Decomposition and Core Variable Definition

    • Exit Visibility: Determined by spatial layout (e.g., turns, obstacles), lighting conditions, and signage clarity, affecting the probability of individuals directly discovering an exit.
    • Information Asymmetry: Some individuals possess additional information (e.g., hidden exits) due to experience or communication, leading to differences in decision-making capabilities.
    • Key Metrics: Evacuation time, exit usage balance, congestion level.

  2. Establishing a Basic Behavioral Model

    • Individual Decision Rules: Assume individuals prioritize visible exits; if not visible, they rely on memory or others' behavior.
      • Example: Set an individual's probability of detecting an exit formula \(P_{\text{detect}} = k \cdot \frac{1}{d} \cdot e^{-\alpha \cdot \theta}\), where \(d\) is distance, \(\theta\) is the line-of-sight angle, and \(k\) and \(\alpha\) are adjustment parameters.
    • Information Classification: Individuals are divided into three categories:
      • Fully Informed: Know all exit locations (e.g., staff).
      • Partially Informed: Only know visible or main exits.
      • Uninformed: Rely entirely on following or random movement.

  3. Simulating Information Propagation and Following Effects

    • Information Diffusion Mechanism: Fully informed individuals can communicate information to neighboring individuals, with propagation probability decaying as distance increases.
    • Herd Effect Modeling: Uninformed individuals follow the movement direction of the nearest crowd with probability \(P_{\text{follow}}\), potentially leading to suboptimal exit clustering.
    • Dynamic Game Analysis: Partially informed individuals may weigh the expected benefits of "heading to a visible exit" versus "following seemingly informed individuals."

  4. Coupled Impact Analysis of Visibility and Information Asymmetry

    • Scenario Comparison:
      • High Visibility + Low Information Asymmetry: All exits are quickly utilized, leading to efficient evacuation.
      • Low Visibility + High Information Asymmetry: Main exits become overly congested, while hidden exits are underutilized.
    • Critical Point Identification: Simulations reveal that when the degree of information asymmetry exceeds a threshold, evacuation time increases nonlinearly due to chain delays caused by local congestion.

  5. Optimization Strategy Design

    • Enhancing Visibility: Reduce obstructions, increase lighting, or implement dynamic indicators (e.g., flashing arrows).
    • Information Balancing:
      • Pre-training: Ensure a certain proportion of individuals are familiar with all exits.
      • Real-time Broadcasting: Use loudspeakers or mobile notifications to disseminate hidden exit locations.
    • Guidance Personnel Deployment: Place guides in low-visibility areas to directly correct crowd flow direction.

  6. Model Validation and Parameter Sensitivity Testing

    • Use simulation software (e.g., AnyLogic) to adjust visibility parameters and information distribution, comparing evacuation time curves.
    • Sensitivity Analysis: For example, expanding the information propagation radius by 10% may reduce evacuation time by 15%, but excessive propagation could cause new congestion.

Conclusion
By quantifying the interaction between visibility and information asymmetry, targeted evacuation strategies can be designed. For instance, in stadium evacuations, combining signage systems with broadcast alerts can avoid local bottlenecks caused by information disparity. Practical applications require balancing costs (e.g., installing smart indicators) and benefits (time reduction).