Published in 1975
This report sets forth procedures for utilizing survey skid data with consideration given to testing variabilities and relationships between the three testing devices used in Virginia namely, the Virginia Department of Highways & Transportation's trailer, the Virginia Highway & Transportation Research Council's trailer, and the Council's Stopping distance car. Within test series variability, or testing precision, as well as day-to-day variability due to systematic errors is discussed, and a method of determining confidence limits for site averages is indicated. Application of the site averages against an assumed minimum standard utilizing confidence intervals is demonstrated. Current testing frequencies are reviewed in light of the testing variabilities determined and reductions are suggested. Relationships between the testing devices in use since the summer of 1974 are verified and modified as necessary based on 1975 correlation data.
Last updated: January 29, 2024