Figure 4.

Guiding fixations and the visual pivot strategy. This frame in this is taken about 2 s after the frame in Figure 3: the driver has now arrived at the far road (TH2s) region and begun to turn into the bend. Gaze is looking ahead, guiding steering, and anticipating the upcoming end of the bend. (A). Most of the time gaze is concentrated in a small region of the visual field—the guiding fixation (GF) region. The concept of guiding fixations can be operationally defined in terms of time headways, between about 1–2 s TH. (B). The GF region acts as a visual pivot, from which saccades are launched, and to which saccades return. Scenery and in-car fixations are eyes off the road fixations, the rest are eyes-on-the-road fixations. Gaze polling: i. saccade lands further ahead than the far road GF region and returns (look-ahead fixation, forward polling) ii. saccade made back to the near road and the back to GF region (return fixation, backwards polling). Tangent point fixation: saccade to the tangent point (a travel point on the inside lane edge). GF OKN: future path waypoint (or reference point) fixation. For these Guiding Fixations (the majority), the eye does not remain stable in its orbit: these guiding fixations are “tracking fixations.” The line of sight is locked onto locations in the 3D scene one is moving through. (Note: This is a schematic representation; what is here indicated by individual gaze points may be glances comprised of multiple fixations; and not all glances in the periphery always return to the pivot in a rigidly mechanical way).