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A critical assessment is made of tunnel wall interference corrections, indicated testing limits, and the data correlations for yawed truck models inside a solid-wall test section, using a modified pressure-signature method. Two models, a full-size tractor-trailer and a similar half-scale model, were tested in the 9 x 9 meter wind tunnel of the National Research Council of Canada (NRCC). Both models were yawed through ±14° with full length and truncated trailer bodies for the purpose of determining wind-averaged drag and exploring the real aerodynamic testing limits due to tunnel interference. The correction method employed an algorithm to perform an iterative solution to determine the strengths of potential sources, sinks, and horseshoe vortices for given inputs (measured ceiling pressures, side force, yaw and roll moments, as well as dimensional data). The output comprised corrections to tunnel dynamic pressure and yaw angle, and a horizontal buoyancy effect.