The design method described in this section is based on a modification of the original Kearby method and was first recommended to TxDOT by Texas Transportation Institute in 1981 (Epps et al., 1981). It is still the method most commonly used by TxDOT today. A formal design method such as this can effectively serve to guide inexperienced personnel through the “art” of seal coat design and to train personnel including inspectors, designers, and laboratory personnel. Correction factors for binder application rates for varying conditions including traffic and surface condition may be developed for conditions unique to a district and will ensure a much faster learning curve for inexperienced personnel. Examples of some adjustment factors, which were developed by the Brownwood and Abilene districts, are shown in . Sample calculations are shown in .

A design method such as described herein should be used to determine initial binder and aggregate application rates, but it should not take the place of good engineering judgment. Field conditions will require the adjustment of both binder and aggregate rates.