Motion platforms can be used to provide vestibular cues in a driving simulator, and have been shown to reduce driving speed and acceleration. However, motion platforms are expensive devices, and alternatives for providing motion cues need to be investigated. In independent experiments, the following eight low-cost nonvestibular motion cueing systems were tested by comparing driver performance to control groups driving with the cueing system disengaged: (1) seat belt tensioning system, (2) vibrating steering wheel, (3) motion seat, (4) screeching tire sound, (5) beeping sound, (6) road noise, (7) vibrating seat, and (8) pressure seat. The results showed that these systems are beneficial in reducing speed and acceleration and that they improve lane-keeping and/or stopping accuracy. The seat belt tensioning system had a particularly large influence on driver braking performance. This system reduced driving speed, increased stopping distance, reduced maximum deceleration, and increased stopping accuracy. It is concluded that low-cost nonvestibular motion cueing may be a welcome alternative for improving in-simulator performance so that it better matches real-world driving performance.

Car racing is a mentally and physically demanding sport. The track time available to train drivers and test car setups is limited. Race car simulators offer the possibility of safe, efficient, and standardized human-in-the-loop training and testing. We conducted a validation study of a race car simulator by correlating the fastest lap times of 13 drivers during training events in the simulator with their fastest lap times during real-world race events. The results showed that the overall correlation was .57 ( p = .044). Next, the effect of brake pedal stiffness (soft: 5.8 N/mm vs. hard: 53.0 N/mm) on racing performance was investigated in the simulator. Brake pedal stiffness may have an important effect on drivers' lap times, but it is impractical to manipulate this variable on a race car during a real-world test session. Two independent experiments were conducted using different cars and tracks. In each experiment, participants ( N = 6 in Experiment 1 and N = 9 in Experiment 2) drove alternately with the soft and hard pedal in eight 20-min sessions (Experiment 1) or six 15-min sessions (Experiment 2). Two hypotheses were tested: (1) the soft pedal yields faster cornering times for corners that include a long brake zone, and (2) the hard pedal yields more high-frequency brake forces. Experiments 1 and 2 confirmed the second hypothesis but not the first. Drivers were highly adaptable to brake pedal stiffness, and the stiff pedal elicited higher pedal forces and more high-frequent brake pedal inputs. It is concluded that the racing simulator is a valuable tool for driver assessment and for testing adoptations to the human–machine interface.