Module 3 - Important Functions and Relationships of Visual Perception and Driving

Topic 1: Laws of Nature

Gravity is the natural force that constantly pulls all things to the earth and affects an object’s weight. Center of Gravity is a point where the mass of the vehicle is concentrated and balanced.  The higher the center of gravity, the more unstable the vehicle becomes. When a driver brakes, accelerates, or corners, the G forces are amplified.

Kinetic energy is the energy an object possesses due to its speed, or velocity (v) and its mass (m). The faster the object moves, the more energy it collects. A heavier moving object will have more kinetic energy than a lighter object moving at the same speed.

Momentum refers to the quantity of motion an object has.

Inertia: an object’s tendency to resist any change in its state of motion.

The things that transfer weight from one point of the vehicle to another are acceleration, turning,

Steering input/cornering, and surface traction.

Pitch - Vehicle shifts weight from front to rear or rear to front

Roll- Vehicle shifts weight from side to side

Yaw - vehicle rear-load transfers to the left, right, or back and forth (fishtail motion)

Topic 2: Vision and Driving

Vision: The eyeball’s ability to distinguish the number, shape, and color of an object.

Perception: How we interpret and understand information gathered by any of the five senses.

Drivers base driving decisions on about 90% of what they see.

Drivers base driving decisions on about 10% of all on what they hear or feel.

The eyes don’t tell the brain what they see; the brain tells the eyes what to look for.

Visual Search Pattern: Your visual lead time should be at least 20-30 seconds.

Focal vision allows you to read and see details

Paracentral vision allows you to maintain path of travel.

Peripheral vision is more sensitive to light and motion. It helps to orient individuals to the environment.

Your field of vision is the area you can see while looking straight ahead.

Your field of vision is also everything within 180 degrees in front of you.

Visual acuity tests measure the level of detail your eyes can see (individually and together) in optional light conditions.

Nearsighted: you can see near things more clearly than distant ones.

Farsighted: you can see distant things more clearly than near ones.

Some hazards for seeing at night are lack of light, wildlife become active, people driving at night are more likely to be intoxicated or fatigued, and inner and outer sources of concentrated light cause glare.

For depth perception, you need both eyes to judge depth between two objects.

Depth perception allows you to judge gaps, speed, and distance of other vehicles.

Ways to improve your field of vision include cleaning windows inside and out, cleaning vehicles outside lights, inspecting wiper blades for damage and effectiveness, adjusting mirrors properly.