This paper describes a set of experiments investigating the interaction between the location of eye fixations and the detection of unexpected motion while driving. Both psychophysical and real-world observations indicate that there are differences between the upper and lower visual fields with respect to driving. We began with psychophysical experiments to test whether the detection of unexpected motion Is inherently different in the upper and lower visual fields. No difference was found. However, when texture was added to the driving surface, a large difference was found, possibly due to optokinetic nystagmus stimulated by the texture. These results were confirmed in a driving simulator, and their implications for head-up displays (HUDs) explored. We found that the same upper/lower field asymmetry could be found with digital HUDs but not with analog HUDs. These experiments illustrate how virtual environment technology can connect knowledge from psychophysical experimentation to more realistic situations.