This Recommended Practice provides a procedure to locate driver seat tracks, establish seat track length, and define the SgRP in Class B vehicles (heavy trucks and buses). Three sets of equations that describe where drivers position horizontally adjustable seats are available for use in Class B vehicles depending on the percentages of males to females in the expected driver population (50:50, 75:25, and 90:10 to 95:5). The equations can also be used as a checking tool to estimate the level of accommodation provided by a given length of horizontally adjustable seat track. These procedures are applicable for both the SAE J826 HPM and the SAE J4002 HPM-II.