13.5.3.1.3 Driving Behavior

The interaction between vehicles is modeled using the Wiedemann 1974 and 1999 carfollowing models. Such models are assigned for different driving behavior containers. The Wiedemann 1974 is used for ‘Urban (motorized)’ link types that represent urban arterial roads and streets. The Wiedemann 1999 is primarily used for ‘Freeway (free lane selection)’ link types to model freeway operations. With updated parameters, Wiedemann 1999 is often used for ‘Cycle-Track (free overtaking)’ links to model bicycle lanes. The link type ‘Footpath (no interaction)’ does not monitor the interaction between users of this link type. As such, it can be used for pedestrian movements and walkways and crosswalks. shows all the carfollowing parameters in a Vissim model that can be changed. However, it is recommended to only modify CC0, CC1, and CC2 when adjusting the car-following parameters. Car following and lane changing parameters are shown in .
Table 13-8: Car-Following and Lane Changing Parameters
Parameter
Description
CC0
Standstill distance. The distance between two vehicles when they are not moving
CC1
Following distance. A time distribution of the speed-dependent portion of safety distance.
CC2
Longitudinal oscillation. Defines the distance in which a driver will intentionally move closer to the car it is following.
CC3
Perception threshold for following. Defines when the beginning of the deceleration process occurs.
CC4
Negative speed difference. Low values result in more sensitive reactions when following vehicles.
CC5
Positive speed difference. Low values result in more sensitive reactions when following vehicles.
CC6
Influence speed on oscillation. Defines how car-following distance impacts the acceleration of vehicles.
CC7
Oscillation acceleration value. Minimum value used when a driver is following another vehicle.
CC8
Acceleration value when starting from a standstill.
CC9
Acceleration value at 80 km/h
Diffusion Time
This is the maximum amount of time that a vehicle can wait at an ESD before the vehicle is removed from the network
Min. Clearance
The minimum distance between two vehicles after a lane change occurs
Safety distance reduction factor
The safety distance of a following vehicle after a lane change, the safety distance of the vehicle making the lane change, and the distance to the preceding, slower lane change.
Maximum deceleration for cooperative braking
Defines how much a trailing vehicle will brake to allow an adjacent vehicle to change into its lane.
Use implicit stochastics
When this option is checked, safety distance, desire acceleration, desired deceleration, minimum lateral distance is stochastic to reflect variations in human perception. When this option is not checked, the characteristics listed above are non-variable.