In-vehicle time • FacIVT • (in)direct attribute of vehicle journey items
+ PuT-Aux ride time• FacAXT •(in)direct TSys attribute
+ Access time • FacACT
+ Egress time • FacEGT
+ Transfer walk time • FacWT
+ Origin wait time • FacOWT
+ Transfer wait time • FacTWT
+ Number of transfers • FacNT
+ Number of operator changes • FacOC
+ Extended impedance • Factor
Notes
- PuT-Aux ride time
The time spent in a transport system of the PuT-Aux type enters the PJT as a separate value and can be weighted by any transport system attribute. It is furthermore required as a skim value.
- Modeling bonus and malus
The in-vehicle time can be multiplied by an attribute of the vehicle journey items (and the PuT-Aux time by a TSys attribute respectively) in order to model the vol/cap ratio (for example the availability of seats) or other aspects of usability (for example the level of comfort).
- Number of transfers
The PuT line and the PuT Aux are included equally in the calculation of the transfer frequency. If there is a passenger trip chain between two vehicle journeys, switching between the vehicle journeys is not counted as a transfer event (Forced chainings).
In the case of circle lines, where the start stop point is the same as the final stop, continuing beyond the final stop is also not considered a transfer (Using Visum: Creating a circle line).
- Number of operator changes
Operator changes cannot occur due to PuT-Aux path legs.
Origin wait time
With the following equation, the origin wait time, OWT, can be determined from the service frequency of all connections.
OWT = A • (assignment time period / service frequency)E
- With A = 0.5 and E = 1, the origin wait time corresponds to half the mean headway.
- With A = 1.5 and E = 0.5, a root function is created which assumes that passengers have better knowledge of timetables in the case of low service frequency.
The origin wait time is the same for all connections of an OD pair. Including them in the PJT is therefore just like a constant supplement. The OWT output as a skim matrix, however, can be important for the network analysis.
Transfer wait time
The transfer wait time models smooth transfers in zero time or slightly more than zero time.
The extended transfer wait time models that transfers are ideal not in zero time (or slightly more) but if they take a few minutes. A lot of timetable information retrieval systems also do not offer connections that contain "smooth" transfers.
With the extended transfer wait time, you can also "penalize" transfers in Visum that are too short. For this, the program uses a non-linear function which calculates a weighted wait time that depends on the user-defined ideal transfer wait time, which then enters the perceived journey time. Instead of the regular transfer wait time, the extended transfer wait time can enter the PJT calculation. But it can also be saved as a separate skim.
The used weighting function f takes the following shape.
- As an argument, the actual transfer wait time t is set, which is the time that passes between the arrival of the passenger at the stop point and the departure of the vehicle journey.
- The weighted wait time f(t) is thus defined as
- (t - t0)n + c if t < t1, and
- f(t) = t if t ≥ t1.
t1 and c result from the boundary conditions f(t1) = t1 and f'(t1) = 1, that is from the differentiable composition of both parts of the function at position t1.
- Essential is: t0 is the transfer wait time considered ideal. For the extended transfer wait time, this variable may depend on the required walk time and thus needs to be parameterized as follows:
Factor times walk time plus constant
Due to the polynomial shape of f, the weighted wait time f(t) is the least precisely at the position t = t0.
Around t0, f(t) increases symmetrically.
With increasing t, function f(t) approaches the linear asymptote t.
- Example
By default, n = 2 and t0 = 5 is set.
Due to the boundary conditions f(t1) = t1 and f'(t1) = 1, t1 = 5.5 and c = 5.25 results from these parameters.
- For a transfer with time t = 0, weighting is calculated as follows, i.e. a very high penalty term:
f(0) = t02 + c = 25 + 5.25 = 30.25
- A transfer with time t = 3 results in a considerably better value:
f(3) = (3 - t0)2 + c = 22 + 5.25 = 9.25
- A transfer with time t = 5 reaches the optimum:
f(5) = (5 - t0)2 + c = 02 + 5.25 = 5.25
- If t continues to increase, the weighting deteriorates again, for example with t = 10:
f(10) = (10 - t0)2 + c = 25 + 5.25 = 30.25
