Page 381 - 360.revista de Alta Velocidad - Nº 5

Economic, geographical and time-based exclusion as main factors inhibiting Spanish users from choosing High
Speed Rail

Economic theory assumes that the individual i will choose the option with the highest utility.
As explained by Ben-Akiva (1985), in the general form of a binary choice model, the probability
that user i will choose alternative j can be expressed as follows:

In our case, the probability of choosing HSR or other transport mode (not HSR) is here computed,
from a given origin o, for a given purpose s, in the time period h and to a given destination
d. Specifically, the dependent variable equals to 1 if the user travelled by HSR, or 0 if other
transport mode was chose. The explanatory variables X chosen to model whether users chose
k
HSR for interurban trips are reported in Table 6.
Table 6 – Explanatory variables included in the model specification

Then, the binary logit approach predicts the so-called logit of the odds ratio, L , given multiple
k
explanatory variables X . The model specification finally adopted has the classical form of a
k
binary logit model:

where p is the probability of choosing HSR and the argument of the natural logarithm is called
odds (Bewick, et al., 2005). The relationship between p and explanatory variables Xi can be
written as follows:

International Congress on High-speed Rail: Technologies and Long Term Impacts - Ciudad Real (Spain) - 25th anniversary Madrid-Sevilla corridor 379