20 May
2011
20 May
'11
6:16 p.m.
Patty--you are right about the precision but in the transportation world
folks tend to like and use 2 decimal places. Of course in the
transportation world folks also like small area data which too has its
statical concerns.
Patty Becker wrote:
You don't need 2 decimal places. The data
don't support that level of
precision!!!
Patty Becker
At 06:06 PM 5/20/2011, you wrote:
--
Ed Christopher
708-283-3534 (V)
708-574-8131 (cell)
FHWA RC-TST-PLN
4749 Lincoln Mall Drive, Suite 600
Matteson, IL 60443
Don't mind Steve--he is just giving a
shameless plug for the NHTS ;-)
In the ACS you can get a vehicle occupancy for people commuting to
work. It takes a little work but you can calculate it from table
B8301 (mode to work). The trick is what assumption do you use for the
5-6 people per car (maybe 5.5) cohort and the 7+ category. In 1990 we
actually knew the factor and it was around 0.3xxx. Try a few numbers
and see what you like, 7.2 people per car; 7.3, but I would not go
over 7.5
Now for another shameless plug. One of the beauties of the CTPP
tabulations is that there is a vehicle occupancy table for the work
commuters. Unfortunately, with the 3-year CTPP it is only carried out
to 1 decimal so everything is 1.1. I believe the 5-year tab due out
sometime in 2013 will have 2 decimal places.
Back to the NHTS, it's strength here is that it has all trip purposes.
Polzin, Steve wrote:
-------------------------------------------------------------------------------------------------
Patricia C. (Patty) Becker 248/354-6520
APB Associates/SEMCC FAX 248/354-6645
28300 Franklin Road Home 248/355-2428
Southfield, MI 48034 pbecker(a)umich.edu
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ctpp-news(a)chrispy.net
http://www.chrispy.net/mailman/listinfo/ctpp-news there is no data on occupancy only household
vehicle availability.
The 2009 NHTS would have vehicle occupancy data.
From: ctpp-news-bounces(a)chrispy.net
[mailto:ctpp-news-bounces@chrispy.net] On Behalf Of Jim Hubbell
Sent: Friday, May 20, 2011 4:35 PM
To: ctpp-news(a)chrispy.net
Subject: [CTPP] private vehicle occupancy data from ACS
I'm trying to track down an estimate of private vehicle occupancy
from the 2009 ACS 1-year estimates, and am having some difficulty
finding the table that includes this calculation. Can anyone provide
me with the ACS table number? Any help would be greatly appreciated.
Thanks,
Jim Hubbell
Transportation Planner II
Mid-America Regional Council
600 Broadway, Suite 200
Kansas City, MO 64105-1659
816.701.8319 voice
816.421.7758 fax
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--
Ed Christopher
708-283-3534 (V)
708-574-8131 (cell)
FHWA RC-TST-PLN
4749 Lincoln Mall Drive, Suite 600
Matteson, IL 60443
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