[CTPP] Changes in Workers per HH and Vehicles per HH (long post)

TO: CTPP-News Okay, I'm starting a new thread on a new topic. This is related to the national and metropolitan area changes in employed residents per household, and vehicles per household. IF AND WHEN responding to my message, please "snip out" my very long message. What caught us by surprise in our region was a DECLINING number of workers per household, 1990 to 2000. (We were predicting that employed residents per household would increase from 1.40 in 1990 to 1.45 in 2000, instead, the Census 2000 shows us at 1.37 workers per household! This trend in workers/HH also explains to a certain extent our under-prediction of zero-vehicle households: we expected our zero-vehicle HH share to decrease from 10.3 to 9.3 percent; instead, it decreased only from 10.3% in 1990 to 10.0% in 2000.) NATIONALLY, the number of employed residents / household declined from 1.28 in 1990 to 1.24 in 2000. (Note: employed residents also includes workers residing in group quarters / military barracks, so it's not exactly workers in households, it's workers divided by households. Employed residents is defined as the civilian employed plus armed forces.) National Data: Year Households Employed Residents EMPRES/HH 1990 91,947,410 117,390,130 1.277 2000 105,480,101 130,873,649 1.241 Of the 36 largest metropolitan planning organizations in the US (population > 1 million), 30 show DECREASING workers/household, 1990-2000, and only 6 show INCREASING workers/household. Those with an increase: Salt Lake City (1.40 to 1.51), Denver (1.33 to 1.36), Portland (1.29 to 1.31), Phoenix (1.26 to 1.27), Pittsburgh (1.10 to 1.11), and Tampa-St. Pete (1.07 to 1.08). Washington, DC (1.533 to 1.400) and Miami (1.31 to 1.19) show the LARGEST DECREASE in workers per household. Why? I don't know. (I wish I knew what was going on. Eventually, with the SF3 and PUMS datasets we will be able to understand which, if any, age-sex cohorts are showing increasing or decreasing labor force participation rates....) Question: are there any other databases (CPS, AHS, ACS, etc.) that can be used to corroborate this trend in decreasing workers per household? ************************************************ In terms of vehicles per household, and vehicles in household, the national census-based statistics are: Year Households Households-in-Vehicles Vehicles/Household 1990 91,947,410 153,701,085 1.67 2000 105,480,101 177,459,681 1.68 (I assumed 3.35 vehicles per 3+ vehicle household, based on 1990 Census data on vehicles/3+ vehicle household. The 177.5 million household vehicles is probably accurate, plus-or-minus 1.0 million. The 1990 HH vehicles is from the CTPP/SE.) Census data shows a 15.5 percent increase in household vehicles, 1990 to 2000. THIS COMPARES TO NATIONAL VEHICLE REGISTRATION DATA available on FHWA's Office of Highway Information Management web site: Private AND Commercial Vehicle Registrations (excluded Publicly-owned vehicles) Year Autos Trucks Auto+Truck 1990 132,164,330 53,101,089 185,265,419 2000 132,247,286 85,004,999 217,252,285 % Change 0.01% +60.1% +17.3% So, the 15.5 percent increase in household vehicles, US, is somewhat consistent with a 17.3 percent increase in private-plus-commercial vehicle registrations. And as should be expected the Census-based HH vehicles is between the total auto registrations, and total auto+truck registrations. (Unfortunately, the Census data at our regional level don't reconcile with our California DMV registration trends. The Census suggests a 8.5 percent increase in household vehicles in the SF Bay Area, compared to a 12 to 14 percent increase in auto+truck registrations. "County Registrations Are Problematic"....) Census Trends in V/HH and share of HH with zero-vehicles: 17 of the 36 largest MPOs in the US show declining vehicles per household between 1990 and 2000. Vehicles per household range from a low in the New York region (NYMTC, 1.01 to 0.98 vehicle/HH) to a high in Salt Lake City (WFRC, 1.91 increasing to 1.95). 8 of the 36 largest MPOs show INCREASES in the share of households with zero vehicles. NYMTC (New York) leads the way with 40.6% (1990) to 41.0% (2000) zero-vehicle HH share. Other MPOs showing increases in the share of zero-vehicle households: Newark (13.2 to 13.5%), Los Angeles (8.7 to 10.1%), Las Vegas (8.0 to 9.5%), San Diego (7.7 to 8.0%), Seattle (7.6 to 7.9%), Sacramento (7.4 to 7.8%), and Phoenix (6.9 to 7.0%). It's fascinating looking at these WEST COAST metropolitan areas that show INCREASING SHARE OF HOUSEHOLDS WITH ZERO VEHICLES....Who are these households, and what's their story? (Stay tuned, we need the PUMS to dig down to see what's up!) (In terms of this MPO database I'm working on, I'm re-organizing it and will post it on our FTP in the next few days. Given the issues with changing county composition of MSAs and CMSAs, I've gone back to the original county-level CTPP/SE data from the 1990 Census, and the county-level data file from the Census 2000 DP234, to re-construct MPO-compatible tables. I am doing this a) because I can and who's going to stop me?; b) it's helpful to AMPO; and c) I'm interested if data is just screwy for my region, or screwy on a nationwide basis or for other MPOs.) That's about all I have for now. Cheers, Chuck Purvis *********************************************** Charles L. Purvis, AICP Senior Transportation Planner/Analyst Metropolitan Transportation Commission 101 Eighth Street Oakland, CA 94607-4700 (510) 464-7731 (office) (510) 464-7848 (fax) www: http://www.mtc.ca.gov/ Census WWW: http://census.mtc.ca.gov/ ***********************************************