Problem is that this is a gross vehicle count at the household level, and does not relate to commuting, so I don't think it solves the problem. The vehicle occupancy issue relates to work trips. Perhaps there is a vehicle count available elsewhere in ACS, though the suggestions advanced by others should get the number to a pretty good level of precision.

Wendell Cox

On Sat, May 21, 2011 at 1:23 PM, Chu, Xuehao <> wrote:
Table B25046 has a total vehicle count.

Data Set: 2009 American Community Survey 1-Year Estimates
Survey: American Community Survey
NOTE. Although the American Community Survey (ACS) produces population, demographic and housing unit estimates, it is the Census Bureau's Population Estimates Program that produces and disseminates the official estimates of the population for the nation, states, counties, cities and towns and estimates of housing units for states and counties.
For information on confidentiality protection, sampling error, nonsampling error, and definitions, see Survey Methodology.


 Margin of Error

Aggregate number of vehicles available:

Owner occupied

Renter occupied

Source: U.S. Census Bureau, 2009 American Community Survey

From: [] On Behalf Of Alan []
Sent: Saturday, May 21, 2011 8:36 AM
Subject: RE: [CTPP] RE: private vehicle occupancy data from ACS

Thanks Ed: I didn't want to have to correct Steve.   Isn't there a total
vehicle count also somewhere in ACS? I recall using it to calc the top
category so that it all comes out right.

-----Original Message-----
From: []
On Behalf Of Ed Christopher
Sent: Friday, May 20, 2011 6:06 PM
Subject: Re: [CTPP] RE: private vehicle occupancy data from ACS

Don't mind Steve--he is just giving a shameless plug for the NHTS ;-)

In the ACS you can get a vehicle occupancy for people commuting to work.
 It takes a little work but you can calculate it from table B8301 (mode
to work).  The trick is what assumption do you use for the 5-6 people
per car (maybe 5.5) cohort and the 7+ category.  In 1990 we actually
knew the factor and it was around 0.3xxx.  Try a few numbers and see
what you like, 7.2 people per car; 7.3, but I would not go over 7.5

Now for another shameless plug.  One of the beauties of the CTPP
tabulations is that there is a vehicle occupancy table for the work
commuters.  Unfortunately, with the 3-year CTPP it is only carried out
to 1 decimal so everything is 1.1.  I believe the 5-year tab due out
sometime in 2013 will have 2 decimal places.

Back to the NHTS, it's strength here is that it has all trip purposes.

Polzin, Steve wrote:
> there is no data on occupancy only household vehicle availability.  The
2009 NHTS would have vehicle occupancy data.
> From: []
On Behalf Of Jim Hubbell
> Sent: Friday, May 20, 2011 4:35 PM
> To:
> Subject: [CTPP] private vehicle occupancy data from ACS
> I'm trying to track down an estimate of private vehicle occupancy from the
2009 ACS 1-year estimates, and am having some difficulty finding the table
that includes this calculation.  Can anyone provide me with the ACS table
number?  Any help would be greatly appreciated.
> Thanks,
> Jim Hubbell
> Transportation Planner II
> Mid-America Regional Council
> 600 Broadway, Suite 200
> Kansas City, MO  64105-1659
> 816.701.8319 voice
> 816.421.7758 fax
> ------------------------------------------------------------------------
> _______________________________________________
> ctpp-news mailing list

Ed Christopher
708-283-3534 (V)
708-574-8131 (cell)

4749 Lincoln Mall Drive, Suite 600
Matteson, IL  60443

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Wendell Cox
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