First of all you have to determine what kind of soil we are dealing with. Not all types of soil are suitable for a successful use of Road Rapid. The two major requirements are that there is at least 15% of clay, loam or clayey silts in the soil and the soil must have a pH degree which does not exceed 8.
Hereafter you will find some classification schemes which will guide you to find the type of soil and if it is suitable for the use of Road Rapid.
As a remark: only sand is not suitable for Road Rapid use, but loamy sand and sandy loam are. As you see in the scheme, just sand is a very small amount of the total types of soil.