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<br />vehicle track width during a maneuver, and hence <br />answers obtained through its use should not be consid- <br />ered sufficiently accurate to be deemed standards. <br /> <br />Page 24 shows a turning track plot for a straight <br />truck. Also given on page 24 is a procedure for deter- <br />mining the maximum wheelbase (WB) for a straight <br />truck given the maximum over-all straight truck length <br />(OL).OL is given in the "Summary of Size and Weight <br />Urnits" chart under the section "Length in Feet" as <br />"Truck." The equation for WB given on page 24 is based <br />on the fact that for most van 1ype straight trucks .6 of <br />the van body length is mounted ahead of the rear axle. <br /> <br />Pages 25 and 26 show the turning track plots for two <br />tractor-semitrailers making 900, 1800 l 2700 l and 3600 <br />turns. <br /> <br />Page 27 shows the turning track plot for doubles <br />making a 300 turn. <br /> <br />Backing <br /> <br />Page 28 is included to show: (1) the turning track <br />plot procedure described in this Appendix can be <br />adopted for various maneuvers including backing, and <br />(2) some of the steps necessary in backing a tractor- <br />semitrailer. As already mentioned, the space required for <br /> <br />backing into a dock need not be more than that for <br />pulling out from a dock; hence, it may never be neces- <br />sary to make a backing plot. <br /> <br />Pull-Out Space <br /> <br />Page 29 presents a method of determining the space <br />necessary to pull out from a terminal dock. <br /> <br />Maximum Offtrack Plots <br /> <br />Pages 30 through 33 show plots of the maximum <br />offtrack equation given in SAE J695 (1971 SAE HAND- <br />BOOK). These plots show, for the particular subject <br />vehicle, the maximum off track at a specific tractor <br />turning radius and the particular equation used to deter- <br />mine the off track plotted. The value of off track, for a <br />particular tractor turning radius, obtained with the equa- <br />tion is the maximum of which the subject vehicle is <br />capable. The degree of turn at which this maximum off- <br />track occurs for the subject vehicle, at a particular trac- <br />tor turning radius, cannot be determined through the use <br />of the equations. Since the degree of turn at which the <br />maximum offtrack shown on the plots in pages 30 <br />through 33 occurs is unknown, these plots should not be <br />used when minimum track is desired for some specific <br />degree of turn. Normally maximum off track will occur <br />when the vehicle negotiates a curve of around 2700. <br />