HART

Visual Information

Our first line of defence is our eyes. Although good vision alone is no defence, it is the principal input to our computer, the brain. Studies indicate that ninety percent of our impressions of riding are visual. To focus on a specific event or item in traffic, we have to rely on central vision which is only a cone measuring 3 degrees in width in the central part of our sight. Our central vision is used for such things as estimating distance and reading details in the traffic scene.

Getting good visual information when riding

Peripheral vision, although not as sharp as central vision, is more sensitive to light and movement than central vision. It helps us detect important information coming into the traffic scene, even though we are not looking directly at some objects.

Visual Cues and Eye Movement

What visual cues are actually used in riding? Vision research answered this question by devising a method to describe a riders visual search process. This was done by means of an eye movement recording system. This device recorded where the rider was looking while riding along the highway.

The recording system allowed the researchers to document eye movement patterns. They determined that inexperienced operators have an active search pattern with many fixations on unimportant clues. With experience, this progresses to an in-out pattern, sharing fixations for near lane position with glances ahead. The pattern exhibited by experienced riders is more desirable and effective.

Learning Good Eye Habits

The ultimate goal in eye movements while operating a motorcycle would be a pattern of far ahead fixations in the projected path of travel, using side vision to maintain lateral positioning. Since this pattern is essential for valid perception, the question becomes “How do you develop good eye habits?”

There are at least three concepts that are critical to developing good eye habits:

  • Concentrate (focus) on your intended path of travel and move in traffic maintaining adequate margins in all directions.
  • Aim your vision well ahead by keeping your eyes up.
  • Force your eyes to move frequently so that you receive a wide field of information.

In the ideal visual search process, our eyes function in a series of rapid, jerky movements. They fixate ever so briefly in between the movements. These fixations are rapid and last only between .1 and .3 of a second. The eyes gather visual information during these brief fixations.

Bad Effects on the Visual Search Process

Physical limitations that adversely affect this visual search process:

  • Fatigued riders tend to fixate lower and to the left, thus limiting their vision to only a small portion of the overall scene.
  • Alcohol-impaired riders fixate straight ahead and don’t move their eyes often.
  • Accident data indicates that alcohol is a contributing factor in some motorcycle accident fatalities.

These limitations degrade our ability to see potential hazards which can result in higher risk taking. Getting good visual information is critical for riders because everything that follows involves decisions based on that information. The key is to practice moving your eyes quickly and frequently to gather information. Knowing what is critical requires good judgement based upon knowledge and skill.