Folks:
As a transportation modeler and one who is constantly looking for good data that will help
us better calibrate and validate our forecasting procedures, the early review of the CTPP
macro data and the trends are of course interesting and an exciting preview of what is
about to come.
What I would hope, however, is that before jumping to lots of conclusions about what has
happened and what is most likely to happen in the future, we would continue to organize
and plan for the release and use of the data at the TAZ level in our MSA's and provide
guidance (and support) to those who maintain the models in these areas on how to use the
data to re-validate (and improve) the local forecasting models, especially in smaller
MSA's.
I know that there are several superb analysts on this list (and the TMIP list too) and
that for many of the larger MSA's, that such a detailed validation plan and process is
in place and ready to go. I wonder, in some cases, for some of the smaller or new UA.s
and even some of these newer UC's, that when the CTPP detailed data is finally
released, whether the time and resources will be spent to look at the data at the
community and also the corridor/TAZ level and then to see if the existing forecast models
that are up and running need fine tuning, and whether they are demonstrating consistency
(validity) in the forecast mode for the Year 2000.
Also, as we all are seeing very clearly, the non-work travel purpose continues to have an
increasing impact on our system needs.
So, I am also curious to know if there is has been a defined process in the smaller
jurisdictions to improve data collection efforts for these non work travel modes, as well.
It is my hope that with the raft of local governmental fiscal constraints that such
important and vital data collection efforts were not cut back too much, if at all
possible.
Ed Herlihy
Transportation Consultant
Reston VA.
----- Original Message -----
From: Alan E. Pisarski
To: Putta, Viplava ; ctpp-news(a)chrispy.net
Sent: Monday, June 03, 2002 4:58 PM
Subject: Re: [CTPP] Census JTW
There is a chart in CIA II that shows that women lag about a 1/2 later than men
nationwide on average. It will be interesting to see what has happened to that distrib
since. AEP
----- Original Message -----
From: Putta, Viplava
To: ctpp-news(a)chrispy.net
Sent: Monday, June 03, 2002 4:26 PM
Subject: [CTPP] Census JTW
Yes, carpooling went down drastically from 1980-90 and obviously not as dramatic from
1990-2000. We had over 23% JTW trips by carpool in 1980 Nationwide! 1990 it was down to
just over 13% (Nationwide).
I would argue that given the economic condition in 1990 (beaten down) vs. 2000 (just
when the .com bubble was to burst but still upbeat) - losses in carpooling and transit are
not as significant.
Comparing 1995 NPTS and Census 2000 I have the following to offer:
· Trip chaining (the part that goes with JTW) is up during 1990s (NPTS)
· Huge buy-in in favor of 'flex schedules' during 1990s has essentially
marginalized the significance of JTW (there was a drop of more than 5% from 1990 to 1995
in peak hour trip starts in our case)
· Each trip taken by transit would have a front end and a back end trip - (park
& ride or ride & walk) - Census asks for only one mode that covered most of the
distance (is comparable to 1990) thereby undercounting all other trips;
· Vehicle occupancy rate for HBW is a little bit different from what JTW
indicates for the same reason as above - our HBW VOR is less than what census shows
(Tulsa)
Another factor - I have noticed with NPTS is - Women as a percent of peak hour
commuting public is higher than for men (13.6% men vs. 19.7% women in 1995 for Tulsa). It
could be because women tend to keep more regular hours than men. May be
'Rideshare' programs should focus on Women-only carpools as a potential market
share.
Whatever it may be, we might notice with CTPP an increase in share of women in
commuting during peak hours - to somewhat contributing to the erosion in transit
patronage, decline in carpooling and increase in commute times.
Viplav Putta
INCOG