This paper documents the vehicle response of a tractor-semitrailer following a sudden air loss (Blowout) in a steer axle tire while traveling at highway speeds. The study seeks to compare full-scale test data to predicted response from detailed heavy truck computer vehicle dynamics simulation models. Full-scale testing of a tractor-semitrailer experiencing a sudden failure of a steer axle tire was conducted. Vehicle handling parameters were recorded by on-board computers leading up to and immediately following the sudden air loss. Inertial parameters (roll, yaw, pitch, and accelerations) were measured and recorded for the tractor and semitrailer, along with lateral and longitudinal speeds. Steering wheel angle was also recorded. These data are presented and also compared to the results of computer simulation models. The first simulation model, SImulation MOdel Non-linear (SIMON), is a vehicle dynamic simulation model within the Human Vehicle Environment (HVE) software environment. This program includes a vehicle dynamic model capable of simulating vehicle motion in 3-dimensional environments and includes Brake Designer, ABS Simulation, and Tire Blowout models. The second model, TruckSim, is a vehicle dynamics software package which focuses on large tractor-semitrailer vehicle dynamics. TruckSim does not currently carry a blowout model; however, modifications were made to the vehicle model in an attempt to simulate the full-scale blowout test.The results of a full-scale instrumented test of a tractor-semitrailer performed at the Transportation Research Center, in East Liberty, Ohio are presented. An instrumented tire blowout test was performed at approximately 55 mph with a tractor and semitrailer in a one half payload condition. This left steer axle tire blowout test was performed on a dry concrete surface.Vehicle parameters and inputs for the computer simulation models were obtained from the actual vehicle or motor vehicle manufacturer's specifications. The simulation results, in terms of vehicle dynamics responses, are compared to the full-scale test data. The simulation variables were input by using the recorded data in terms of throttle, steering, and braking. Some of the tire blowout parameters in the simulation program were however adapted as discussed below to minimize the differences between the outputs of the full-scale test and the computer simulations.