Hello,

Both Kevin Tierney and Alex Karner are quite right about there not being a “distance” table in the ACS/CTPP files.

But now this brings up an interesting secondary question: exactly how is this being calculated in the LEHD product? Unless everyone who commutes to work drives their own car in a mostly uncongested and non-tolled environment, this is actually a lot more complicated to “get right” than one might think, even if a road network-based find-the-minimum-path approach is used. I presume there is documentation about how the distance-based calculations are being done (surely it is something more than a straight-line between two centroids, multiplied by a national factor to represent circuity for auto travelers, but that would be my guess), but a quick search of LEHD and LODE documents did not reveal the answer.

Ken Cervenka

FTA Office of Planning

From: ctpp-news-bounces@chrispy.net [mailto:ctpp-news-bounces@chrispy.net] On Behalf Of Kevin Tierney
Sent: Friday, December 02, 2016 2:27 PM
To: ctpp-news@chrispy.net
Subject: Re: [CTPP] Distance travveled to work

No. Some users noted a desire for it in the recent CTPP Assessment, but others indicated they get that information from their travel models.

From: ctpp-news-bounces@chrispy.net [mailto:ctpp-news-bounces@chrispy.net] On Behalf Of Alex Karner
Sent: Friday, December 02, 2016 2:21 PM
To: ctpp-news@chrispy.net
Subject: Re: [CTPP] Distance travveled to work

ACS has commute time but not distance. With CTPP you can use OD flows to calculate distance using network approaches or assuming straight lines. No way to get distance directly as far as I know.

-Alex

--
Alex Karner, PhD

Assistant Professor

School of City & Regional Planning
Georgia Institute of Technology
alexkarner.com

From: Mara Kaminowitz <mkaminowitz@baltometro.org>
To: "ctpp-news@chrispy.net" <ctpp-news@chrispy.net>
Sent: Friday, December 2, 2016 2:07 PM
Subject: [CTPP] Distance travveled to work

Hello,

Is there a table in ACS or CTPP that gives the distance traveled to work? I know it's in LEHD but I'd like to pin down another source.

Mara

Mara Kaminowitz, GISP
GIS Coordinator
.........................................................................
Baltimore Metropolitan Council
Offices @ McHenry Row
1500 Whetstone Way
Suite 300
Baltimore, MD 21230
410-732-0500 ext. 1030
mkaminowitz@baltometro.org
www.baltometro.org

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