Part B

SUPPORTING STATEMENT

Part B. Collections of Information Employing Statistical Methods.

1. Describe potential respondent universe and any sampling selection method to be used.

The respondent universe for annual HPMS data collection is ultimately each of the State transportation agencies. Each year by June 15, the States (in addition to the District of Columbia and Puerto Rico) are required to submit their HPMS data to FHWA Headquarters in compliance with the procedures and coding contained within the HPMS Field Manual. These data are mostly collected by State and local agencies for reporting on all open to public roads. A sampling technique is used for various data items not needed on a universe basis. This sampling scheme consists of a random sampling of roadway sections stratified by area, functional classification of roadway, and traffic volume group strata and is the only real statistical aspect of the HPMS program. For further details please refer to the HPMS Field Manual.

2. Describe procedures for collecting information, including statistical methodology for stratification and sample selection, estimation procedures, degree of accuracy needed, and less than annual periodic data cycles.

All procedures for collecting, reporting, and statistical methodologies can be found in Chapter VII and Appendices C and D of the HPMS Field Manual. Random samples are to be drawn by the State that conform to the traffic volume group strata and desired precision levels and confidence interval based on area and roadway functional classification (as referenced in HPMS Field Manual Appendix C). Samples remain in place and generally tend to be constant over time so as to reduce the data collection burden on State and local agencies (the reason for statistically-based sampling). Sample panel updates are done by the State on an as-needed basis. There are no less than annual periodic data cycles. HPMS data are to be reported annually by June 15 based on the previous calendar year.

3. Describe methods to maximize response rate.

All 50 States in addition to the District of Columbia and Puerto Rico are required to report HPMS data annually.

4. Describe tests of procedures or methods.

Aside from initial tests and development of the HPMS program in 1978, there are none. HPMS software exists that can be used to test the sample validity however, based on the submitted State HPMS data.

5. Provide name and telephone number of individuals who were consulted on statistical aspects of the IC and who will actually collect and/or analyze the information.

No legacy contact information is available for individuals consulted on the statistical aspects of the IC. Current contact for the Highway System Performance Division (HPPI-20): (202) 366-0175.

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