Only a few gates were visible ahead and then disappeared before the observer passed them. Dependent variables included constant and variable errors in the passage point and in the position of the turn with respect to each gate. Performance was high with 1 gate in the visible band, whereas 2 or 3 visible gates added little improvement. Performance was best witha preview distance of 0 gates, declined with 1 invisible gate and deteriorated markedly with 2 invisible gates. There were no effects of speed, indicating that the results are due to the number of gates rather than time.
Subjects generally control steering on-line with respect to the next visible object.
A view of additional objects does not provide much advantage, consistent with a lak of planning ahead. Supported by NIH EY10923.