This paper reviews the development of criteria for human vibration tolerance, leading up to the proposed ANSI Standard (S3. 18-197x), based on the ISO Document (ISO/TC 108). This proposal is analyzed to show why its adoption is opposed in its present form, and what specific changes are recommended in keeping with the data considered most reliable. Here, special emphasis is placed on the “absorbed power” concept developed by Pradko and Lee.Practical applications of the recommended criteria to ride evaluation are explored with specific reference to the type of measurements made. The preferred instrumentation becomes a logical outgrowth of the evaluation process.