This book details the recommended practices that resulted from research conducted in Phases I and II of the Heavy Truck Crashworthiness Cooperative Research Project. It covers the development, evaluation, and recommendation of test procedures that could be used to evaluate occupant protection in heavy trucks. Restraint systems, cab structures and cab interior components are covered. Draft SAE Recommended Practices (RPs) were developed for tests that evaluate each of these elements in manners consistent with typical real-world accident sequences.