[sustran] [Kyoto2020] Re: Transportation Modal Choice in Asian Cities

[Lee Schipper]

An additional frustration is that trip shares do not describe
motion/mobility in passenger-km well, because trip length by mode varies
so much. And without  trip distance and mode by purpose, the results are
kind of a wash....but still this is a step forward.

Lee Schipper
Director for Research, EMBARQ
World Resources Institute
10 "G" St NE, Washington DC 20002
TLF 1 202 729 7735
FAX 1 202 729 7775

http://www.embarq.wri.org/en


>>> czegras at mit.edu 6/24/2005 11:35:35 AM >>>
Dear all,

I think that a comparable, international set of data on mode share
across 
cities would be a valuable tool to help better gauge where 
differences/commonalities exist, where they come from, what lessons we
can 
learn, etc.

But, we all know that the comparability issue is fairly challenging.
Having 
been involved in a few efforts to come up with similar types of mode
share 
'inventories,' I know that the problem of secondary, tertiary (and
further 
on) sourcing is an issue, making it often quite difficult to track down
the 
real source of information. This should not be taken lightly. For
example, 
I recently found an instance where a Latin American government's public

presentation of a city's mode share actually (inadvertently, I can only

hope) switched the bus/auto share (relative to what the raw data and
more 
detailed technical reports actually showed) - and I have since seen
this 
incorrect figure cited elsewhere.

We know that the results are susceptible to: 1. definition of sampling

frame (e.g., all persons, >5, adults, urban, suburban, metropolitan,
etc. ) 
2. definition of trip (all 'outings' in the public realm, >200 m;
motorized 
trips, etc.); 3. Sample size and related issues such as quality of the

expansion/corrrection factors; 4. Day of the week; 5. Time of the year;

among other factors.

That said, I think it would be of extremely high value if the
international 
agencies, professional associations, etc. came up with a set of
standards 
for conducting household (oh, and what about that poor cousin,
freight...) 
origin-destination surveys and, importantly, REPORTING clearly those 
results (assumptions, etc. etc.) so that comparison might ultimately be

possible. These standards already exist in many countries, but
implementing 
them and ensuring transparency is fairly critical. At the very least,
any 
development organization that finances data collection should ensure
that 
those standards are met and, furthermore, ensure that the data produced
is 
public (at least in aggregate form), with all influencing factors 
(partially enumerated above) clear.

Regards,

Chris



From: "V. Setty Pendakur" <pendakur at interchange.ubc.ca>
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         <006d01c578c9$3ee546a0$7701a8c0 at WALTER>
Date: Fri, 24 Jun 2005 07:53:54 -0700
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Subject: [sustran] Re: Transportation Modal Choice in Asian Cities
Message: 3

During the past 20 years, we have been saying at TRB, CODATU and WCTR
that 
aggregating modal splits without making sure that they have a common
base 
for the split, simply and blatantly distorts the data systems for
policy 
formulation and implementation , with a bias favoring the MVs.  It is
time 
that all of us, including the international funding agencies, recognize

this bias.  If NMT data is not included in the modal splits, such data

should be separated as specifically a data set not including NMT.  If 
possible, estimates can be made for NMT and such data can be 
adjusted.  However, combining, willy nilly, all data into one set will
only 
repeat and reinforce the historic bias to favor the MVs.

Data sets should also be separated by chronological periods.  If you
have 
several cities in Asia and the data set covers the period 1980-2005 all
in 
one file, comparisons for policy making would be meaningless.  This
applies 
to Africa also.

Whatever tabulations ADB wish to produce, we certainly don't need
another 
data set with a lot implicit biases.

Best wishes.  Setty.

Dr. V. Setty Pendakur
Professor Emeritus, University of BC
Honorary Professor, National Academy of Sciences of the PRC
Chair, TRB-ABE90 & Director, ITDP
President
Pacific Policy and Planning Associates
702--1099 Marinaside Crescent
Vancouver, BC, Canada  V6Z 2Z3
Phone: 604-263-3576; Fax:604-263-6493
----- Original Message -----
From: <mailto:whook at itdp.org>Walter Hook
To: <mailto:eric.britton at ecoplan.org>eric.britton at ecoplan.org ; Asia
and 
the Pacific sustainable transport
Cc: <mailto:newman at central.murdoch.edu.au>Peter Newman ; 
<mailto:chuizenga at adb.org>chuizenga at adb.org ; 
<mailto:Kyoto2020 at yahoogroups.com>Kyoto2020 at yahoogroups.com ; 
<mailto:kenworth at central.murdoch.edu.au>Jeff Kenworthy ; 
<mailto:lfwright at usanet.jca.ne.jp>lfwright at usanet.jca.ne.jp 
Sent: Friday, June 24, 2005 7:30 AM
Subject: [sustran] Re: Transportation Modal Choice in Asian Cities

i agree we need to at least separate out the modal split data that has

walking and nmt included and that which doesnt, as there is huge
variation 
in the way walking trips are counted.

Walter Hook, Ph.D.
Executive Director
Institute for Transportation and Development Policy (ITDP)
127 West 26th Street, Suite 1003
New York, NY 10001
Ph:  (212) 629-8001
Fax: (212) 629-8033

Promoting environmentally sustainable and equitable transportation
worldwide