[sustran] Income and Trip-Making (was transport and asian econ. debacle)

[Paul Barter]

Bambang Susantono said:

>Paul is right that the number on my illustration is about trip, not on
>people.
>
>However, using the same ARSDS 1985 data again to illustrate his point
>does make me confuse. Despite many caveats in ARSDS, the biggest one is
>that ARSDS never did income survey.

Thanks for this question. Having now looked back at the fine print , I
should clarify:
The ARSDS study used the state of the housing of their household
respondents to make assumptions about their income.   So you are right they
did not have direct information on incomes. They based their assumptions on
expenditure and other data from the National Social Expenditure Survey
(SUSENAS) of 1984. (pp. 1-11 and 1-12 of the Arterial Road System
Development Study in Jabotabek Metropolitan Area -ARSDS- Draft Final
Report, Main Report, July 1987).


Chris Zegras also asked:
>>"Low income"  people who were 47.5 % of the sample:  took only 0.61
>>motorised trips per day (0.20 private and 0.41 public) on average.  On the
>>other hand, those with lower-middle, upper-middle, or high incomes
>>(altogether 52.5 percent of the sample)  took 1.11 motorised trips per day
>>on average (0.63 private and 0.48 public).  This implies that the richer
>>52.5 % of the population took  67% of all motorised trips and the poorer
>>47.5% of the population had only 33 % of all motorised trips.     (looking
>>at vehicle owners versus non-vehicle owners would probably be even more
>>striking).
>
>Paul, it would be interesting to see the walk and nmt trips from this data,
>was it taken?

Using the same source (some calculations based on data on p. 1-34 of ARSDS
Draft Final Report, Main Report, July 1987) I get:
The low income 'half' of the population took 0.91 non-motorised trips per day.
The higher-income 'half' took 0.70 non-motorised trips per day.

All non-motorised trips were lumped together on this page's data (but on
average 10% of nmt trips were by becak -pedicabs-, 5% by bike and 85% by
foot).

I can't find the 'fine print' stating the definition of a trip but I assume
that they may have excluded very short walk trips (usually 400m or 500m as
the cutoff) as done by some other JICA studies in the region over the last
decade or two.

Does this help?

Best wishes,
Paul Barter.