Model Definition
As a car-following model, the IDM describes the dynamics of the positions and velocities of single vehicles. For vehicle, denotes its position at time, and its velocity. Furthermore, gives the length of the vehicle. To simplify notation, we define the net distance, where refers to the vehicle directly in front of vehicle, and the velocity difference, or approaching rate, . For a simplified version of the model, the dynamics of vehicle are then described by the following two ordinary differential equations:
, and are model parameters which have the following meaning:
- desired velocity : the velocity the vehicle would drive at in free traffic
- minimum spacing : a minimum net distance that is kept even at a complete stand-still in a traffic jam
- desired time headway : the desired time headway to the vehicle in front
- acceleration
- comfortable braking deceleration
The exponent is usually set to 4.
Read more about this topic: Intelligent Driver Model
Famous quotes containing the words model and/or definition:
“It has to be acknowledged that in capitalist society, with its herds of hippies, originality has become a sort of fringe benefit, a mere convention, accepted obsolescence, the Beatnik model being turned in for the Hippie model, as though strangely obedient to capitalist laws of marketing.”
—Mary McCarthy (1912–1989)
“... if, as women, we accept a philosophy of history that asserts that women are by definition assimilated into the male universal, that we can understand our past through a male lens—if we are unaware that women even have a history—we live our lives similarly unanchored, drifting in response to a veering wind of myth and bias.”
—Adrienne Rich (b. 1929)