Hi Charles,
I appreciate your response. After speaking with other folk, now I understand how
everything works. To answer my initial question myself, it seems that CTPP is able to get
the lower/smaller/lowest level data from Census Bureau, which is not the same one open to
public on Census Bureau website, and then aggregate it to TAZ level. Originally I was
thinking everyone was getting the same dataset. Problem solved.
Thanks!
Best,
Xinbo Mi
From: Charles Purvis <clpurvis(a)att.net>
Sent: Friday, August 6, 2021 5:05 PM
To: CTPP ListServe <ctpp-news(a)mailman.chrispy.net>
Subject: [CTPP] Re: CTPP TAZ Data
**** This is an EXTERNAL email. Exercise caution. DO NOT open attachments or click links
from unknown senders or unexpected email. ****
Xinbo:
You are correct that the TAZ (and TAD) data are not available directly through the Census
Bureau’s website. The TAZ/TAD data is only available through the CTPP data site:
http://data5.ctpp.transportation.org/ctpp1216/<https://linkprotect.cudas…
But the data is literally available to everyone. It’s open to the public. I’m certain that
AASHTO, USDOT, the Census Bureau, the State DOTs and MPOs would encourage their use by
government staff, academics, consultants, journalists and interested citizens.
The CTPP data is also summarized at standard census geography levels: state, county,
place, PUMA, census tract, MSA.
There is a lot of background material on the CTPP for you and others to peruse:
https://www.fhwa.dot.gov/planning/census_issues/ctpp/index.cfm<https://l…
https://ctpp.transportation.org/<https://linkprotect.cudasvc.com/url?a=h…
https://ctpp.transportation.org/ctpp-history/<https://linkprotect.cudasv…
http://trbcensus.com/<https://linkprotect.cudasvc.com/url?a=http%3a%2f%2…
Chuck
On Aug 5, 2021, at 2:26 PM, Mi, Xinbo
<xmi@evansvillempo.com<mailto:xmi@evansvillempo.com>> wrote:
Thanks for your information. However, the TAZ level ACS data could not be found on its
website (
https://data.census.gov/cedsci/advanced). When you said “The data crunching and
table production was done inside the Census Bureau.”, did you mean Census Bureau still
processed data at TAZ level and gave it to CTPP but not open to public? I am a bit
confused here because it is said on
census.gov<http://census.gov/> that “In the ACS,
block groups are the lowest (smallest) level of geography published. Block group data are
only available in the ACS 5-year data products.”
Best,
Xinbo Mi
From: Ed Christopher <edc@berwyned.com<mailto:edc@berwyned.com>>
Sent: Thursday, August 5, 2021 3:27 PM
To: CTPP ListServe
<ctpp-news@mailman.chrispy.net<mailto:ctpp-news@mailman.chrispy.net>>; Mi,
Xinbo <xmi@evansvillempo.com<mailto:xmi@evansvillempo.com>>
Subject: [CTPP] Re: CTPP TAZ Data
**** This is an EXTERNAL email. Exercise caution. DO NOT open attachments or click links
from unknown senders or unexpected email. ****
1. TAZs were defined by the MPOs and states using basically a census block to TAZ
equivalency. The data crunching and table production was done inside the Census Bureau.
2. This will all depend on what CTPP gets but it will be census geography. I believe the
ask from the Census Bureau is for block group and tract level data, which likely has some
relationship to the TDM tazs, but the Census Bureau disclosure review board needs to
complete their review first before all the table details are know.
On 8/5/2021 2:58 PM, Mi, Xinbo wrote:
Hi,
I am new to the list and I want to post 2 questions:
1. Since CTPP data is based on ACS data and the lowest level of geography of ACS
data is block groups, how was CTPP data generated at TAZ level?
2. Since TAZ level CTPP data will be discontinued, what will be the best practice to
get TAZ level demographic, socioeconomic and housing characteristics data as input layers
to travel demand model?
Thanks!
Best,
Xinbo Mi
Transportation Engineer
Evansville Metropolitan Planning Organization
1NW Martin Luther King Jr. Blvd. Room 316
Evansville, Indiana 47708
Office Main Line 812.436.7833
www.evansvillempo.com<https://linkprotect.cudasvc.com/url?a=http%3a%2f%2…
<image001.jpg>
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