CALIBRATION OF ILLINOIS ROADOMETERS

Several calibration procedures have been used in Illinois to determine the repeatability of roadometer measurements. The integrator was independently calibrated under static conditions. The roadometer was periodically calibrated by operating the instrument over a field calibration course. Until 1968, annual correlations were made between the roadometer and the CHLOE profilometer. Although the use of these fundamental calibration and correlation concepts indicated when changes in roadometer output had occurred, none of them were entirely satisfactory. To overcome limitations in the established calibration procedures, a new roadometer calibration concept was developed based upon frequency response analysis. The roadometer is a viscously damped spring-mass system; therefore, it has the characteristics which would allow frequency response analysis. In this calibration, response curves were obtained by subjecting the roadometer to sinusoidal forces over a moderate range of frequencies. A standard curve was developed using the average of data from all tests. Data from periodic tests were compared to the standard curve and changes in roadometer output were observed; however, the changes could not be associated with specific components of the roadometer. Therefore, further consideration should be given to the development of equipment capable of analyzing all the major components in the system. On the basis of this study, frequency response analysis appears to be a potentially good method to determine whether the Roadometer response to a given input remains the same from time to time. /FHWA/

  • Supplemental Notes:
    • Sponsored by Illinois Department of Transportation in cooperation with FHWA.
  • Corporate Authors:

    Illinois Department of Transportation

    Bureau of Materials and Physical Research
    126 East Ash Street
    Springfield, IL  USA  62704-4766

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  USA  20590
  • Authors:
    • LaCroix, J E
  • Publication Date: 1975-4

Media Info

  • Pagination: 28 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00130599
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: FHWA-RD-75-S0393 Intrm Rpt.
  • Contract Numbers: IHR-74
  • Files: NTIS, TRIS, USDOT, STATEDOT
  • Created Date: Mar 29 1976 12:00AM