VISSIM 5.30-05 User Manual

5 Base Data for Simulation
step length. Example: With 10 time steps per second (time step = 0.1 s),
the limit is 20% (0.2) of the intended change in acceleration.
The accelerations from standstill have been validated against test vehicle
data in the European research project RoTraNoMo
(www.rotranomo.com) in 2004.
► For trucks, the acceleration/deceleration curves have been adapted to
data from the European research project CHAUFFEUR 2 in 1999.
► For trams and buses, the acceleration/deceleration curves have been set
according to information from the Karlsruhe public transport company
(VBK), 1995.
All curves should be adapted to local conditions (especially the vehicle
fleet) if these are substantially different from Western Europe.
Speed calibration by adjusting the maximum acceleration/deceleration
curves
For all vehicles, the maximum acceleration is affected by the gradient:
► It is reduced by 0.1 m/s² per 1% upwards gradient.
► It is increased by 0.1 m/s² per 1% downwards gradient.
For trucks, the actual acceleration is limited by the desired acceleration
function, too, so the surprisingly high maximum acceleration values for trucks
are only relevant at very low speeds for steep gradients.
The maximum acceleration of a specific vehicle at a certain speed is
somewhere between the maximum value and the minimum value (black lines
without red dots in the maximum acceleration curve dialog).
The position in this range is determined by the following:
► By power and weight for vehicles of a vehicle type with category "HGV".
► By a random value for all other vehicles.
The random value is normal distributed (with average 0.5 and standard
deviation 0.15 but limited to [0..1], so the distance between the average
curve and the and min/max curve is 3.333 times the standard deviation
(SD)).
This results in the following:
- About 70% of the vehicles are in the inner third (-1 SD .. + 1 SD) of
the random values
- And 95% are inside the inner two thirds (-2 SD .. + 2 SD).
Linear interpolation in VISSIM:
- For random values below 0.5 VISSIM interpolates between the min
(0.0) and the average curve (0.5),
- For random values above 0.5 VISSIM interpolates between the
average and the max curve (1.0).
108 VISSIM 5.30-05 © PTV AG 2011