Matching speed production in real and simulated driving environments

Despite geometrically correct optic flow displayed on large Field Of View displays, a common observation in driving simulators and other Virtual Reality systems is that visual speed is underestimated leading to speed overproduction. This may compromise the validity of human behaviour in these environments. In a previous study we have demonstrated that manipulation of the Geometric Field Of View (GFOV) potentially provides a subtle technique to improve speed production, and hence, simulator validity. To determine optimum GFOV settings, the aim of this study was to compare speed production performance in simulated and real driving using identical experimental methods and procedures. This is because (i) speed underestimation may also occur in the real world, and (ii) speed perception and production performance varies widely depending on the methods employed. Results showed that the produced speed was 9% and 4% higher in simulated and real driving, respectively, compared to target speed. On average, drivers drove 5% faster in the simulator compared to the test track. Based on the linear function of GFOV and speed production as determined in our previous study, it was concluded that a GFOV/FOV ratio of 1.119 provides optimum speed production in the TRL driving simulator.