of employers by prohibiting the publication of information about those firms included in the data and requires that researchers be discreet.

  1. Inability: Much data are stored in older information systems designed for a particular purpose, and these systems are often incapable of providing the data in any other way. For example, a city assessor’s system created to produce property tax records might be unable to answer questions about the number of three or more bedroom apartments in a neighborhood. Such basic information is used for estimating population capacity and therefore transportation demand. All the relevant data are in a computer system, but the system was created before commercial database packages were available, and any unique report would require the services of a programmer in a long-forgotten computer language.

  2. Quality: Data may be incomplete, badly documented, or inappropriate for the intended use. An example is the ES202 employment data (see above) collected by states. Information on employment is collected as part of unemployment insurance programs—information that could be useful for transportation planning. Because those collecting the data are focused on the insurance issue, they do not require reporting firms to adhere to the rule about separating employees by place of work. All 8,000 employees of the Minneapolis public schools, working at more than 100 sites around the city, are reported as working at the school district’s downtown headquarters. The data are more than adequate for administration of the unemployment program, but lacking in usefulness for indicating jobs in particular parts of the city.

  3. Lack of standards: Data from various counties may be of the highest standards, yet collected in nonstandard ways, so it becomes difficult or impossible to compare data across counties. A prime example is travel behavior inventories. These are taken infrequently, and standards are not uniform. Federal standards could help solve this problem.

  4. No data: The basic parcel map, showing where people live, does not exist in digital form for much of the country. The Western Governors’ Association (2001) is working to resolve this problem west of the Mississippi, in cooperation with the Bureau of Land Management. Guidelines, good geodetic control, and some kind of financial support seem to be the necessary ingredients.

  5. Federal paradox: State and county governments are unwilling to give their data to any activity involving the federal government because the federal government is then required to make the data available to everyone at no cost. State and local governments often

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