Curt:

I hope my jumping in here doesn’t cross with similar responses from others.  I am on the CTPP subcommittee putting together this set of “business rules,” aka “software requirements.”

 

What Census will need from MPOs, DOTs, and any consultants working in their behalf, is which Census 2010 blocks belong in which TAZs – hence the correspondence table.  Any who want CTPP data for their TAZs will need to delineate them, but it may be that not every MPO wishes to delineate TAZs for the CTPP dataset, so that is optional.  Some MPOs/DOTs may want to continue to use the same TAZs they had in 2000, and that would be fine too.

 

The reference to 600 minimum is there because TAZs with fewer residents or workers may be subject to a margin of error that is large enough to be of concern.  This will simply be a guideline rather than a minimum allowed, because many TAZs need to be small in order to meet local modeling needs.  About half of all TAZs nationwide are actually below 600 in size.  Employment center TAZs may have few or no residents (here in Olympia, the State Capitol Campus has thousands of workers but only one residence), and residential neighborhood TAZs may have few or no workers.  That is how it should be for modeling purposes.  You will be able to define TAZs to meet your needs.

 

The software will be very similar to PSAP.  There will be some added capabilities, such as the ability to import your own datasets connected to the geography – e.g., if you have current employment estimates by TAZ to substitute for 2000 vintage ones.  Unlike PSAP, the software will limit us to using aggregations of 2010 Census blocks to form TAZs.  If I remember correctly, PSAP allowed creating boundaries for Census Designated Places that didn’t necessarily follow the firm rules that govern Census Blocks (i.e., must be able to see it on the ground, such as streets, rivers, power lines, etc.).  I don’t remember if PSAP allowed other examples of varying from Census Blocks, since I tried to create a set of proposed Tract and Block Group boundaries that would avoid raising issues at Census.

 

 

Pete Swensson, Senior Planner

Thurston Regional Planning Council

2424 Heritage Ct. SW

Olympia, WA 98502

(360) 741-2530 (direct line)

(360) 956-7575 (main desk)

(360) 956-7815 (fax)

swenssp@trpc.org

 

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From: ctpp-news-bounces@chrispy.net [mailto:ctpp-news-bounces@chrispy.net] On Behalf Of Curt Hutchings
Sent: Thursday, December 03, 2009 12:19 PM
To: ctpp-news@chrispy.net
Subject: [CTPP] RE: Memo to Census Bureau regarding delineation businessrules

 

Penelope,

Thank you for the opportunity to comment on the draft rules. 

 

Section I. Purpose seems to be contradictory to Section III. TAZ in that Section I. says “In support of the Census Transportation Planning Products (CTPP) the U.S. DOT and the U.S. Census Bureau will obtain census 2010 block equivalencies for Traffic Analysis Zones (TAZs) from Metropolitan Planning Organizations (MPOs) and State Departments of Transportation in 2011.” While Section III. says in the second paragraph under ‘B’ that “MPOs are not required to define TAZs;…”

 

Also,

We at the Dixie MPO in the St. George Utah area have used the services of consultants to help us with modeling and most recently with TAZ delineation.  As others have mentioned the draft states that there is a guideline minimum of 600 resident worker population.  Though it is a guideline it may be somewhat difficult for us to adhere to because we have such a large population of ‘Seniors’ that have moved to the area to retire.  Therefore a large tract or development catering to ‘Seniors’ may actually have very few resident workers.

 

I participated in a similar process with PSAP a few months ago.  Will this process be similar and what is the best way to tie both processes together?

Thanks,

 

email signature 09

 

From: ctpp-news-bounces@chrispy.net [mailto:ctpp-news-bounces@chrispy.net] On Behalf Of Weinberger, Penelope
Sent: Wednesday, December 02, 2009 12:28 PM
To: ctpp-news@chrispy.net
Subject: [CTPP] Memo to Census Bureau regarding delineation business rules

 

Hi All,

 

The Census Bureau asked us to refine this document to help them with their software development effort.  There was a three step process and this is step two.  Step three will be the formal version of the attached memo, due to Census Bureau in early 2010.  At this time we are seeking input on this memo for the formal version.  Please reply directly to me with your comments

 

Please reply by January 8th, 2010

 

Thanks!

 

Penelope Weinberger

CTPP Program Manager

AASHTO

202-624-3556

http://ctpp.transportation.org/home/default.htm

 

It's just as bad to not make a plan as to blindly follow the one you already have.