Transportation Spending by Low-Income California Households ...

Table 4.1
County of Residence for Bay Area Workers, by Income Group
% of Low-
Income
Workers
% of Higher-
Income
Workers
County
% of Poor
Workers
% of All
Workers
Alameda 25.6 23.1 20.2 20.5
Contra Costa 10.8 11.6 13.6 13.4
Marin 3.5 3.3 3.9 3.8
Napa 2.2 2.3 1.7 1.8
San Francisco 14.8 15.2 12.3 12.6
San Mateo 7.5 8.2 11.0 10.7
Santa Clara 23.4 22.2 25.5 25.1
Solano 5.0 5.8 5.2 5.3
Sonoma 7.1 8.3 6.6 6.8
SOURCE: Census 2000 Public Use Microdata Sample.
low-income workers and higher-income workers who stay within the
county to work (about 90% for both). 1
For each of the nine Bay Area counties, we identified the two
neighborhoods with the highest number of low-income residents. 2 For
these two low-income neighborhoods, we then chose likely destination
cities inside and outside the county. The PUMS data do not have
information on the city within each county to which low-income
workers most commonly commute: In the absence of that
information, we use the city with the most jobs in the destination
county. 3 (Chapter 2 and Appendix D both have further details on the
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1 Note that the percentage of workers who stay within the county to work is not
exogenously determined but is linked to the location decision of the workers. Workers
who know that vehicle ownership would impose a heavy monetary burden for them are
more likely to choose a residential location where they will not have to travel to another
county to work.
2 The geographic unit that we used was the Traffic Analysis Zone (TAZ), which we
refer to as a “neighborhood” throughout this report. A TAZ usually includes one or
more Census blocks, block groups, or Census tracts. Note that we selected TAZs with
the highest number of low-income residents, not those with the highest ratio of lowincome
to higher-income residents. The TAZs that we selected often have high numbers
of higher-income residents as well.
3 By the time of publication, more detailed information on job locations for lowincome
workers might be available through Part 2 of the Census Transportation Planning
Package, “Detailed Workplace Tabulations.”
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