FRICTION FACTOR MEASUREMENTS ON NON-UNIFORM SURFACES: SAMPLING FREQUENCIES REQUIRED

It is well known that road surface conditions in winter can vary widely, reflecting the effect of factors such as: (a) local variations in road conditions and vegetation; and (b) variations in structure. It is intuitively obvious that less frequent sampling is required to measure the average friction reliably on long, relatively uniform road sections than on short ones or on ones with more variability. Numerical analyses have been conducted for a wide range of potential road surfaces to investigate sampling requirements by comparing the friction factor that a device would be expected to measure with the actual friction factor. It is concluded that when measuring the average friction factor along the length of a runway or road, the sampling interval should be selected based on the expected variability in surface conditions with respect to friction levels, and also the relative proportion of the overall road or runway length covered by each; the minimum length over which friction factor variations are of concern; and the maximum error that is acceptable. The analyses suggested that sampling intervals should be no more than about 20 to 30 percent of the segment length to keep sampling errors less than 1 to 5 percent. Randomness in the road surfaces will introduce variations in the measured friction factor. The magnitude of the variations is governed by the sampling interval; segment length of interest; total sampled distance; and confidence level. For sampling intervals that are in the range of about 20 to 30 percent of the segment length, the analyses suggested that randomness will introduce variations of about +/-1 and +/-2 percent at one and two standard deviations from the mean, respectively.

• Record URL:
  • http://data.tc.gc.ca/archive/eng/innovation/tdc-summary-13700-13784e-710.htm
• Supplemental Notes:
  • This research co-sponsored by the Ministry of Transportation of Ontario.
• Corporate Authors:

  Transport Canada

  Transportation Development Centre, 800 Rene-Levesque Boulevard West, Suite 600
  Montreal, Quebec  Canada  H3B 2X1

  BMT Fleet Technology, Limited

  311 Legget Drive
  Kanata, Ontario  Canada  K2K 1Z8
• Authors:
  • Comfort, G
  • Singh, S
• Publication Date: 1999-12

Language

• English

Media Info

• Features: Figures; Tables;
• Pagination: 44 p.

Subject/Index Terms

• TRT Terms: Airport runways; Errors; Friction factor; Measurement; Numerical analysis; Pavement components; Representative samples (Testing); Roads; Sampling; Surface course (Pavements); Winter
• Subject Areas: Aviation; Highways; Pavements; Terminals and Facilities; Vehicles and Equipment; I23: Properties of Road Surfaces;

Filing Info

• Accession Number: 00941176
• Record Type: Publication
• Report/Paper Numbers: TP 13784E
• Contract Numbers: T8200-8-8621/001/XSD
• Files: TRIS
• Created Date: Apr 12 2003 12:00AM