Will there be CTPP Tables prepared for areas of 65,000 people or more, or
for areas of 20,000 people or more? If so, when would that occur?
Sincerely
Harry P. Wolfe
Elaine and Ed,
Thank you very much for your answers. They are very helpful.
One more question on this issue. In Eric's explanation- "Using a factor
of 1.5, 1,000 employees would generate 1,500 HBW trips; then you'd need
to divide by two to approximate a CTPP-derived home-to-work trip, giving
you 750 trips." Does he mean comparing "750 trip" to the "CTPP workers"
?
Thanks a lot!
Binbin
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2. RE: A Question - work flow vs. HBW trip rate (Murakami, Elaine)
3. Re: A Question - work flow vs. HBW trip rate (Ed Christopher)
4. Quick TAZ Update (Ed Christopher)
5. Diana Portillo is out of the office. (Diana Portillo)
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Message: 1
Date: Fri, 07 Nov 2008 12:04:59 -0600
From: "John Posey" <john.posey(a)ewgateway.org>
Subject: [CTPP] Re: ctpp-news Digest, Vol 57, Issue 1 (Out Of Office
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I will be out of the office until November 17. Please contact Hilary
Perkins if you need assistance before then.
------------------------------
Message: 2
Date: Fri, 7 Nov 2008 11:27:29 -0800
From: "Murakami, Elaine" <Elaine.Murakami(a)fhwa.dot.gov>
Subject: RE: [CTPP] A Question - work flow vs. HBW trip rate
To: <ctpp-news(a)chrispy.net>
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<195CBC4D6D4C1547BFCE1198D7D6633977AA51(a)fhxwa4.fhwa1.fhwa.dot.gov>
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Yes, the CTPP 2000 uses the Census 2000 and provides a count of WORKERS
AT WORK. Workers at work is generally at least 10 percent lower than
employment or jobs. Also, the Census 2000 allows a response for only 1
job per worker. http://www.fhwa.dot.gov/ctpp/ctppatwork.htm
NCHRP 365 used results from regional household travel surveys AND the
1990 NPTS. (Page 23)
You might want to take a look at the NHTS transferability project that
FHWA completed a few years ago.
http://nhts.ornl.gov/tools.shtml
The work was done by Oak Ridge National Labs and uses the 2001 NHTS
data, and estimates total person trips, total vehicle trips, and trips
by purpose at the tract level. You need to understand how trip
purpose is coded. I glanced at results for census tracts in one county
in Washington State and HBW were about 12% of total trips. Let's say
that the overall average number of household trips is 9 or 10, then 12%
would be 1.1 to 1.2. The transferability project provides trips rates
by household size and vehicle availability.
However, it is very important to understand that a trip from WORK to
SHOP, and then SHOP to HOME, would not be included as a WORK to HOME
(with 1 stop) in the count of HBW trips.
This is why, using the concept of TOURS and TRIP CHAINING has become
increasingly used in travel demand models. The links below are to Nancy
McGuckin's papers (2001 NHTS and 1995 NPTS) on trip chaining:
http://www.travelbehavior.us/projects_files/Trip%20Chaining%20Trends%20i
n%20the%20US%20TRB%20paper%2005-1716%20(2).pdf
http://nhts.ornl.gov/1995/Doc/Chain2.pdf
Hope this helps.
Elaine Murakami
FHWA Office of Planning
_____
From: ctpp-news-bounces(a)chrispy.net
[mailto:ctpp-news-bounces(a)chrispy.net] On Behalf Of Binbin Chen
Sent: Thursday, November 06, 2008 2:18 PM
To: ctpp-news(a)chrispy.net
Subject: [CTPP] A Question - work flow vs. HBW trip rate
Hi,
I'm new in using CTPP data, and am a little confused about the work flow
CTPP provided and work trip.
Basically, CTPP counts workers, not trip. Then can it be used to compute
HBW trip per household? For example, assume 1.5 trips/worker
(NCHRP#365), HBW trip/HH = 1.5*workers/household numbers ?
And How can CTPP work flow compare to NHTS HBW trip rate?
I highly appreciate your help!
Best,
Binbin
Earlier this week the AASHTO CTPP Oversight Board met and reached an
agreement on TAZs for ACS. MPOs and states wishing to create TAZs will
be able to do so during the summer of 2011. This is a change from the
previous schedule (spring of 2009) and now gives everyone more time
along with the benefit of knowing what the block level 2010 population
counts will be when making TAZs. Stay tuned for more details.
In other news from the Census Bureau...
American Community Survey 2005-2007 Data Release — On Dec. 9, the Census
Bureau will release the first set of three-year American Community
Survey data for all geographies with populations greater than 20,000.
The release will provide the first look at detailed socioeconomic and
housing characteristics for geographies between 20,000 and 64,999 since
Census 2000. (Data will be embargoed to the media Dec. 4.)
--
Ed Christopher
708-283-3534 (V)
708-574-8131 (cell)
FHWA RC-TST-PLN
19900 Governors Dr
Olympia Fields, IL 60461
Hi,
I'm new in using CTPP data, and am a little confused about the work flow
CTPP provided and work trip.
Basically, CTPP counts workers, not trip. Then can it be used to compute
HBW trip per household? For example, assume 1.5 trips/worker
(NCHRP#365), HBW trip/HH = 1.5*workers/household numbers ?
And How can CTPP work flow compare to NHTS HBW trip rate?
I highly appreciate your help!
Best,
Binbin
