RE: [census] [CTPP] No Car but Drive Alone to Work

I took a look at the 2008 ACS PUMS data for Cambridge (a good test case here - the city is in a PUMA all by itself). Nearly half of the zero-vehicle drive alone respondents had mode and occupancy imputed. About half of these records also had vehicles available imputed as well. It looks like the imputed mode splits are based on those of all responses from the city, regardless of vehicles available. The drive alone share for workers with zero vehicles in the 2008 PUMS was 13.5%. However, for complete responses (no imputation) the drive alone share was only 9%, while for imputed records it was 28%. Perhaps means of transportation was imputed before vehicles available. ---------------------------------------------------- Paul Reim Chief Planner, Data Resources Central Transportation Planning Staff Boston Metropolitan Planning Organization 10 Park Plaza, Suite 2150 Boston, MA 02116-3968 Phone: (617) 973-8132 Fax: (617) 973-8855 -----Original Message----- From: ctpp-news-bounces(a)chrispy.net [mailto:ctpp-news-bounces@chrispy.net]On Behalf Of Cook, Cliff Sent: Tuesday, March 02, 2010 3:52 PM To: &#39;ctpp-news(a)chrispy.net&#39; Subject: [census] [CTPP] No Car but Drive Alone to Work I'm hoping someone can help me address this question from a colleague. He put together a table from the 2006-2008 ACS showing mode of journey to work by vehicles owned and came up with surprisingly large numbers who do not won a car yet drive alone to work. No doubt, there are a few people who fit this category but my guess is that this largely is the result of either people misunderstanding the question or some sort of coding problem. Here is an excerpt from his email ( the Cambridge here is Cambridge, Massachusetts): I'm looking at ACS data and specifically at cities and percent workers have no car available. From that I'm then looking to see how those workers get to work. The attached worksheet shows my work. What is strange is that it shows for Cambridge that 6.6% of people without a car available drove alone to work. The percent is similar to Boston. And NYC has 3.4% of workers with No vehicles available driving alone to work. So, the question is, how can someone without a vehicle drive to work alone? Do you have any ideas on this? It could be someone doesn't own a vehicle, but drives a friend's car to work. Or has no car of their own, but uses a company car to get to work. But seems like a high number for this. Can anyone shed any light on this? Thanks Cliff Cook ---------------------------------------------------------------------------- - Clifford Cook Planning Information Manager Cambridge Community Development Dept. 344 Broadway Cambridge, MA. 02139 617/349-4656 FAX 617/349-4669 TTY 617/349-4621 email => ccook(a)cambridgema.gov web site => <http://www.cambridgema.gov/~CDD/> _______________________________________________ ctpp-news mailing list ctpp-news(a)chrispy.net http://www.chrispy.net/mailman/listinfo/ctpp-news