# Pedestrian Models#

JuPedSim allows creating pedestrian simulations with different microscopic models. Below is a list of all the models that are currently available. Please refer to the links in the respective section for a detailed discussion of the respective model.

## Collision Free Speed Model#

The collision-free speed model is a mathematical approach designed for pedestrian dynamics, emphasizing the prevention of collisions among agents. The direction in which an agent moves is determined through an isotropic combination of exponential repulsion from nearby agents. The strength of this repulsion is influenced by the proximity to others within their surroundings, treating all directions equally in terms of influence. Agents adjust their speed according to the nearest neighbor in their headway, allowing them to navigate through congested areas without overlapping or obstructing each other. The collision-free speed model takes into account the length of the agent, which determines the required space for movement, and the maximum achievable speed of the agent. This simplified and computationally efficient model aims to mirror real-world pedestrian behaviors while maintaining smooth movement dynamics.

The collision-free speed model is available in two variants in JuPedSim. Both variants implement the same algorithm but differ when it comes to defining model parameters globally vs. per-agent.

In `CollisionFreeSpeedModel`

neighbor and geometry
repulsion parameters are global parameters, i.e. all agents use the same values
and the values are constant over the simulation.

In `CollisionFreeSpeedModelV2`

neighbor and geometry
repulsion parameters are per-agent parameters that can be set individually via
`CollisionFreeSpeedModelV2AgentParameters`

and can be
changed at any time.

A detailed description is available on PedestrianDynamics.

The original publication can be found at https://arxiv.org/abs/1512.05597

## Generalized Centrifugal Force Model#

The Generalized Centrifugal Force Model is a force-based model that defines the movement of pedestrians through the combination of small-range forces. This model represents the spatial requirement of pedestrians, including their body asymmetry, in an elliptical shape with two axes dependent on speed. The semi-axis representing the dynamic space requirement in the direction of motion increases proportionally as speed increases. Conversely, the semi-axis along the shoulder direction decreases with higher velocities.

A detailed description is available on PedestrianDynamics.

Note

The implementation does not allow to modify all parameters described. Espcially the following parameters are defined constant as:

\(r'_c = r_c - r_{eps}\)

\(s_0 = \tilde{l} - r_{eps}\)

\(\tilde{l} = 0.5\)

The original publication can be found at https://arxiv.org/abs/1008.4297

## Social Force Model#

The Social Force Model [1] is a force-based model that defines the movement of pedestrians by the combination of different social forces affecting an individual. The model defines forces that affect an individual:

A driving force

A repulsive force

An obstacle force

The driving force represents a person’s desire to move in a certain direction, independent of other people and obstacles. The repulsive force is caused by the interaction between the individuals and causes them to avoid each other in order to avoid collisions. The obstacle force acts in a similar way to the person force to avoid collisions with obstacles in the environment.

A detailed description is available on PedestrianDynamics.