Census 2000 Supplementary Survey (C2SS)
San Francisco Bay Area

The Census Bureau released data from the Census 2000 Supplementary Survey (C2SS) on November 20, 2001. The C2SS is a small-sample survey of 700,000 households in the U.S., with about 15,300 households interviewed in the Bay Area. Data is only available for large counties and cities with 250,000+ population.

Transportation-Related Highlights of the C2SS for the Bay Area:

• Transit commute shares are on the rise: from 9.5 percent of all commuters in 1990 to about 10.6 percent of all commuters in 2000.
• Work-at-home commute shares are also on the rise: from 3.4 percent of all commuters in 1990 to about 4.0 percent in 2000.
• Driving alone, carpooling and bicycling to work shares are stable, 1990 to 2000.
• Walk-to-work shares are decreasing, from 3.6 percent of commuters in 1990 to 2.8 percent of commuters in 2000.
• The average Bay Area commute is about 3 minutes longer in 2000, increasing from 25.6 minutes in 1990 to 28.4 minutes in 2000.
• Contra Costa County resident workers have the longest average commute in the Bay Area (34.4 minutes), and the longest commute in the Western U.S.
• The share of workers commuting greater than 60 minutes increased from 8.1 percent of commuters in 1990 to 11.2 percent in 2000.
• Mean household income in the Bay Area increased by 17 percent between 1990 and 2000, from $71,100 to $83,200.
• The share of households without vehicles declined from 10.5 percent of regional households in 1990 to 9.0 percent of regional households in 2000.

Regular Census 2000 "long form" data will be released starting summer 2002. The regular "long form" was completed by about 308,000 Bay Area households, and data will be provided at a much finer level of geography.

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Table 1
Share of Workers by Means of Transportation to Work
San Francisco Bay Area (Nine-County Region)
Census 2000 Supplementary Survey (C2SS) and Decennial Censuses
Means of Transportation to Work	1980	1990	2000
Drive Alone	62.8%	68.2%	67.6%
Carpool	16.3%	13.0%	12.9%
Transit	11.4%	9.5%	10.6%
Walk	4.4%	3.6%	2.8%
Bicycle	NA	1.1%	1.1%
Other	3.1%	1.2%	1.0%
Work at Home	1.9%	3.4%	4.0%
Total	100.0%	100.0%	100.0%
Table 2
Average Commute Duration (one-way in minutes) by County of Residence
San Francisco Bay Area (Nine-County Region)
Census 2000 Supplementary Survey (C2SS) and Decennial Censuses
County of Residence	1980	1990	2000	2000, standard error
Alameda	24.6	25.8	30.0	+/- 0.8
Contra Costa	27.2	29.3	34.4	+/- 1.6
Marin	28.7	28.4	30.4	+/- ~3.0
Napa	19.7	21.4	22.5	+/- ~3.0
San Francisco	25.9	26.9	29.6	+/- 0.7
San Mateo	22.8	24.0	25.6	+/- 1.2
Santa Clara	22.8	23.3	25.0	+/- 0.7
Solano	22.2	28.2	30.5	+/- 2.6
Sonoma	22.7	24.1	25.4	+/- 2.1
Bay Area	24.3	25.6	28.4	+/- 0.5
Table 3
Share of Commuters by Commute Duration
San Francisco Bay Area (Nine-County Region)
Census 2000 Supplementary Survey (C2SS) and Decennial Censuses
Commute Duration	1980	1990	2000
< 20 minutes	43.5%	41.0%	36.8%
20 - 29 minutes	21.2%	20.3%	20.3%
30 - 44 minutes	20.5%	21.7%	21.2%
45 - 59 minutes	7.7%	8.8%	10.4%
60 + minutes	7.1%	8.1%	11.2%
Total	100.0%	100.0%	100.0%
Table 4
General Socio-Economic Characteristics
San Francisco Bay Area (Nine-County Region)
Census 2000 Supplementary Survey (C2SS) and Decennial Censuses
Characteristic	1980	1990	2000
Total Population	5,179,800	6,023,600	6,783,800
Households	1,970,500	2,246,200	2,466,000
Mean Household Income (1999 $)	$60,200	$71,100	$83,200
Commuters	2,481,300	3,085,600	3,339,300
Table 5
Share of Households by Vehicles Available
San Francisco Bay Area (Nine-County Region)
Census 2000 Supplementary Survey (C2SS) and Decennial Censuses
Share of Households by Vehicles	1980	1990	2000
Zero Vehicle Households	12.2%	10.5%	9.0%
Single Vehicle Households	35.8%	32.5%	32.4%
Two Vehicle Households	32.6%	36.5%	37.0%
Three-or-More Vehicle Households	19.4%	20.5%	21.7%
Total	100.0%	100.0%	100.0%
Table 6
Completed Interviews for C2SS and Census 2000 Long Form
San Francisco Bay Area (Nine-County Region)
Census 2000 Supplementary Survey (C2SS) and Decennial Censuses
County	C2SS	Long Form
Alameda	1,905	65,400
Contra Costa	1,354	43,000
Marin	~250	12,600
Napa	~250	5,700
San Francisco	7,165	41,200
San Mateo	975	31,800
Santa Clara	2,212	70,700
Solano	500	16,300
Sonoma	686	21,600
Bay Area	~15,300	308,300
Note: Long form completions are MTC estimates based on 1-in-8 sample rate of Bay Area
households. Census 2000 long form data will be available in summer 2002.
The Census 2000 Supplementary Survey (C2SS) is a nationwide test of the "American Community
Survey" (ACS). The C2SS was conducted throughout the year 2000. Approximately 700,000
households were interviewed.

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For more information on Census 2000 Supplementary Survey (C2SS) data, visit the Census Bureau's C2SS web site at: http://www.census.gov/c2ss/www/.

Additional C2SS data is on MTC's FTP site. Point your web browser to: ftp://ftp.abag.ca.gov/pub/mtc/census2000/C2SS/

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Created: December 11, 2001
Updated: December 14, 2001
MTC Contact: David Ory, 510.817.5755, e-mail: dory@mtc.ca.gov.

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