Module 3 : Microscopic Traffic Flow Modeling

Lecture 14 : Car Following Models

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	General motor's car following model Basic Philosophy The basic philosophy of car following model is from Newtonian mechanics, where the acceleration may be regarded as the response of a matter to the stimulus it receives in the form of the force it receives from the interaction with other particles in the system. Hence, the basic philosophy of car-following theories can be summarized by the following equation $$[{\mathrm{Response}}]_n ~\alpha~ [{\mathrm Stimulus}]_n$$ (1) for the nth vehicle (n=1, 2, ...). Each driver can respond to the surrounding traffic conditions only by accelerating or decelerating the vehicle. As mentioned earlier, different theories on car-following have arisen because of the difference in views regarding the nature of the stimulus. The stimulus may be composed of the speed of the vehicle, relative speeds, distance headway etc, and hence, it is not a single variable, but a function and can be represented as, $${a_n^t}= f_{sti}{(v_n,{\Delta{x_n}},{\Delta{v_n}})}$$ (2) where $f_{sti}$ is the stimulus function that depends on the speed of the current vehicle, relative position and speed with the front vehicle.