Decision Models in Skiable Areas - EPFL

4 DATA 8
View that that the Multinominal Logit Model is a generalization of the Binary Logit
Model, the property of IIA is also satisfied by the Binary Logit Model.
The assumption that the random terms are identically and independent causes problems
with alternatives which are correlated. The red bus/blue bus paradox is illustrated
in [2] or an other example in [1].
4 Data
In this section, the obtained data from the part of Verbier are described. Due to the
system utilizing magnetic cards for the ski-pass, it is possible to draw up a detailed list
about the passages on the lifts. For each passage on a lift, the following information is
given:
• Lift number
• Time
• Date
• Ticket number
• Length of validity of the ticket
• Client category (adult, child,...)
All together it is about 15000 passages in the period between the 8. 11. 2003 and 6.
1. 2004. On average a skier takes about 6 times a lift in a day. Unfortunately, the
passages includes only the sector of Verbier, but the model will be developed for the
sectors Verbier and Mont-Fort. This lack of data in one part of the area will produce
some problems in section 6.1.
5 Model of the skiable area of Verbier
In this section the area of Verbier and Mont-Fort is modelled. This two sections are
part of whole area ”4 Vallée”. You can find the exact list of the lifts and ski slopes is in
Annexe B. A graphic of the modelled graph is illustrated in Figure 1. At disposal has
been several maps of the area and two detailed papers about the lifts and ski slopes. It
is clear that some simplifications has to be done.
6 Model of demand in a skiable area
In this section, a discrete choice model for the behavior of skiers in an skiable area is
developed.
The movement of a skier in the area is modelled as follows: It exists a first model,
called ”Lift Model” in continuation, that determines the succession of the lifts to take.
The way from the end of a lift to the begin of the next lift is chosen by a second model,
called ”Ski slope Model”. This means for the simulation, that a skier arriving at the
end of a lift chooses first the next reachable lift, then the way to the chosen lift.
In this project we focus on the ”Lift Model”. This is related to the availability of
data. The data is described in Chapter 4. It describes the succession of taken lifts per