D5 Annex report WP 4 - ETIS plus

D5 Annex WP 4: ETIS DATABASE METHODOLOGY AND DATABASE USER
MANUAL – PASSENGER DEMAND
directly measurable and must therefore be approximated by variables like gross domestic
product (GDP) per capita. Finally the formula also contains variables S i that indicate the
accessibility of urban destinations or transport infrastructures:
T = f ( D , E , S )
i , p
i i i
The resulting figure can be understood as an average annual mobility per person, expressed in
journeys starting at the individual’s place of residence/ location of job and returning to this
place. If one sums up the annual mobilities of all persons k living in region A the resulting figure
is equal to the total number of journeys with purpose p originating in region A:
T A, p =
å
k
T k. p
The estimation results showed – as expected ­ significant differences in travel behaviour across
age classes. The business journeys are dominated by mid­age adults, while for private trips a
mobility ‘peak’ exists for the younger ones. In the latter, the trip rate falls for very young and
elder persons but we found indications that retired individuals tend to have a higher rate than
those below 60/65. The holiday travellers showed not such significant patterns which might be
due to the fact that this kind of journey is something like a ritual for most of us – the annual
holidays are a must. These findings have to be analysed permanently in a more detailed way as
soon as new surveys like DATELINE are available but we are confident that the major impacts
for mobility are covered already in the chosen approach.
4.5.2 The choice of destination
While the first step generates the originating passenger transport flows, the second step spreads
them between the available destinations. The related approach is based on the idea that an
observed sample population indicates the attractiveness of various destinations by its chosen
destinations.
If we observed e.g. k persons travelling from an origin A and we know that n of them travel to
destination B and m to destination C, then the weighted attractiveness of B and C must reflect
the shares n/k and m/k. Formally expressed as:
Share(B/ i A ) = n
k = f (X B
, C AB
)
f (X L
, C AL
)
where Share(B/i A ) is the share of trips destined for a certain place B for an individual i living in
A. This proportion could be expressed by a utility for visiting a certain destination B compared
to the overall sum of all chosen destinations L for a specific sample population of origin A.
The utilities are functions of the attractiveness of the destination under consideration and a
deterrence function expressing the impedances to be surmounted on the way from A to B. The
attractiveness could be identified by the region­specific indicators as mentioned in the last
section.
å
L
20
Document3
27 May 2004