The Home Lift, Position and Rehabilitation (HLPR) Chair, developed at the National Institute of Standards and Technology (NIST), has unique capabilities and a unique shape as compared to conventional wheelchairs and powered chairs. The evaluation of its static and dynamic stability is necessary to ensure rider safety. Recently, the HLPR Chair was converted into an autonomous forklift for the manufacturing industry. The HLPR forklift includes articulated forks that replace the chair from the original HLPR Chair design. Both the HLPR Chair and HLPR forklift prototypes can carry approximately 114 kg (250 lb) beneath an upper rotation joint (i.e., rotates the seat or the forks). HLPR stability was evaluated based on the American National Standard (ANSI) and the International Organization of Standardization (ISO) wheelchair and forklift standards. Also, new test methods were created and tested that are currently not provided in these standards because of HLPR's unique lift and rotation capabilities. The following report details the standard and new test methods and test results.