Trunk highway system, by utilizing the existing relationship between 30 hv and the average daily traffic /adt/ at the permanent traffic recorders /ptr/ . Hourly traffic volumes were registered automatically at each ptr. All the ptr were grouped according to annual traffic pattern, and all mileage on the rural system was assigned to a group on the basis of similarities of traffic pattern. Estimates of adt could then be obtained for any rural location by multiplying the 24-hr traffic count by the appropriate group mean monthly factor. The reliability of adt estimates obtained in this manner was tested by statistical methods involving the simulation of coverage station operations at ptr locations. Relationships between the 30 hv and adt were then studied. Regression analysis indicated that there was a linear relationship between 30 hv and adt at ptr installations. The stability of the relationship showed that the group estimating equations could be used to obtain satisfactory working estimates of interpolated or extrapolated values of traffic volumes in the 30th highest hour.
Abstract