About 43 million U.S. residents report that they change their own oil. The majority (35 million) of people who change the motor oil in their own vehicles dispose of their used oil by taking it to a recycling center or gas or service station. However, approximately 5 percent of those who change their own oil (or 2.3 million people) report that they use disposal methods that could harm the environment, for example, pouring the oil down a drain, on the ground, or placing it in their garbage.
The Bureau of Transportation Statistics (BTS) surveyed 1,000 households during January, May, and September of 2002 as part of its monthly Omnibus Household Survey program. Other results from the survey show that, on the average, an additional 4 million adults report that they dispose of the oil from their vehicles by using it as a lubricant for other equipment or they take it to some other facility for recycling.
Among the roughly 1.6 million residents who offered reasons for not disposing of their oil in a proper manner (Figure 1), about 60 percent reported that they either had never heard of recycling used oil (.6 million) or there is no recycling center in their town or area (.4 million). An additional 40 percent reported that or the location of the center was not convenient (.3 million).
Data presented in this issue of OmniStats are taken from several issues of the BTS Omnibus Household Survey. Data are preliminary and are subject to change. The target population for the survey is the US non-institutionalized adult population (18 years of age or older). Results are based on a completed sample of 1000+ households that are randomly selected using a list-assisted random digit dialing (RDD) methodology. The findings summarized in this report are estimates derived from a sample survey. Sample surveys contain two major components of error-sampling and nonsampling error.
Sampling Error. Sampling error occurs because findings are based on a sample, rather than on the entire population. The total respondent pool for the Omnibus Survey is 1,000+ for an estimated sampling error of about ±3% at the 95% confidence level. Sampling error will be larger for sample subgroups (such as males or disabled persons) and for survey items that do not apply to all members of the sample (e.g. sample members who flew on a commercial airline during the 30 days prior to the survey). Standard error estimates for each Omnibus Survey item are available on the BTS website for the Omnibus Survey at http://www.bts.gov/omnibus/household/index.html. After selecting the month of interest, choose "Marginal Frequency Distributions."
Nonsampling Error. Estimates are subject to various errors during the survey process, such as data collection, response coding, transcription, and data editing errors. These errors would also occur if a complete census was conducted under the same conditions as the sample survey. Explicit measures of the effects of these errors are not available. However, stringent quality control procedures were followed during data entry and the questionnaire was reviewed and pretested in an effort to minimize nonsampling errors associated with data entry and questionnaire design. Nonresponse error is a function of both the nonresponse rate and the differences, if any, between respondents and nonrespondents