HVTIS Part B_2018

TMAS 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 TMAS data collection is trucks operating on pubic highways within each of the States (including the District of Columbia and Puerto Rico).

A sampling scheme covering both continuous (24 hours per day, 7 days per week, and 365 days per year) and short term sampling (48 hours counting) is stratified by area, functional classification of roadway, traffic volume and vehicle classification group strata is used.

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 Section II, III, IV and V of the Traffic Monitoring Guide (TMG) and Chapter 6 of the Highway Performance and Monitoring System (HPMS). 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 the TMG Section 2 Chapter 2, 3, 4 and Appendix 2-B). 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.

Precision levels are different depending on the functions of the roadway types (e.g., interstate vs. local roadways). The specific precision levels are outlined in Chapter 6 of the HPMS Field Manual.

HVTIS data are to be reported monthly within 20 days after the close of the month for which the data were collected.

3. Describe methods to maximize response rate.

Data collection by the State highway agencies are through machinery installed on the roadways. The FHWA has offered State highway agencies various alternatives in submitting data including online submittal, email, and actual CD mail in.

4. Describe tests of procedures or methods.

Aside from initial tests and development of the TMG manual in 1985, American Society for Testing and Materials (ASTM) 1318 describes test of procedures and methods. Vehicle Travel Information System (VTRIS) and Travel Monitoring Analysis System (TMAS) software and system can be used to test the sample validity, based on the submitted State HVTIS 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 Travel Monitoring & Surveys Division David Jones, (HPPI-30): (202) 366-5053.

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