# A formulation of the relaxation phenomenon for lane changing dynamics in an arbitrary car following model

## TL;DR

This paper introduces a general relaxation model for lane changing dynamics in traffic microsimulation, improving realism and accuracy by preventing overreaction to lane change maneuvers and enabling better simulation of traffic breakdowns.

## Contribution

It develops a versatile relaxation framework applicable to any car following model, addressing a gap in modeling lane change effects and traffic breakdown phenomena.

## Key findings

- Relaxation improves the realism of lane change simulations.
- The model prevents overreaction to lane change maneuvers.
- Relaxation is essential for accurate traffic breakdown modeling.

## Abstract

Lane changing dynamics are an important part of traffic microsimulation and are vital for modeling weaving sections and merge bottlenecks. However, there is often much more emphasis placed on car following and gap acceptance models, whereas lane changing dynamics such as tactical, cooperation, and relaxation models receive comparatively little attention. This paper develops a general relaxation model which can be applied to an arbitrary parametric or nonparametric microsimulation model. The relaxation model modifies car following dynamics after a lane change, when vehicles can be far from equilibrium. Relaxation prevents car following models from reacting too strongly to the changes in space headway caused by lane changing, leading to more accurate and realistic simulated trajectories. We also show that relaxation is necessary for correctly simulating traffic breakdown with realistic values of capacity drop.