Vision & Driving

90% of your decisions are based on information you gather with your eyesPeripheral Vision=To the sidesCentral Vision=In the frontVertical Vision= Up & DownFocus Vision=Targeting

Vision Characteristics

Focus Vision

Central Vision

Peripheral Vision

Peripheral Vision

Motion and Color Changes

Focus Vision (Focal/Foveal)

Visual Lead, Targeting, Signs, Signals

Central Vision (Limited Fringe Area)

Referencing, Path of Travel, Sightlines

Visual Fields in Operation

Driver’s Useful Vision Areas

Gathering Useful Visual Information

Focus Vision Area (Focal) 3 to 5 degrees of useful information

Targeting Skills Establishing Visual Lead Reading Signs and Interpreting Signals

Driver’s Useful Vision Areas

Gathering Useful Visual Information

Central Vision Area (Inner Fringe)30 to 36 degrees of useful information

Vehicle to Roadway Reference

Viewing Path of Travel

Viewing Line of Sight to Target Area

Driver’s Useful Vision Areas

Gathering Useful Visual Information

Peripheral Vision (Outer Fringe)

175 to 185 degrees of useful information

Motion Changes

Color Changes

Visual Fields in Operation

Path of TravelTarget

Standard Visual Reference for Lane Position 1

When focus vision is on the target at the end of the path of travel, the central or inner fringe vision will allow the driver to see the placement of vehicle in the roadway...

SpeedSpeed Effect on Effect on VisionVision

As you go faster:

central vision decreases and blurs

peripheral vision decreases

sudden changes in steering may cause

exaggerated vehicle movements

VISION FIELDS NARROW

Vision Sightlines/Travel PathsVision Sightlines/Travel Paths

Line of Sight Limitations or Restrictions

When line of sight is restricted or blocked, a speed adjustment is needed until visual lead, target area, and the line of sight are restored...

Speed and Effect on VisionSpeed and Effect on Vision

allows more time to get information;

increases peripheral vision field, giving time for adequate response; and

places more space between other users and your vehicle, so sudden steering changes are held to a minimum.

Looking farther away from your vehicle lengthens or

increases line of sight (LOS) and path of travel (POT)

areas which:

Determining Following IntervalsDetermining Following IntervalsFixed Object or Shadow

One Thousand One

One Thousand Two

One Thousand Three

One Thousand Four

1/2 sec 3/4 sec Total

Vehicle Ft./Sec. Following Interval Steer Brake Brake

Speed Travel 2 Sec. 3 Sec. 4 Sec. Dist. Dist. Dist.

Time, Speed, and DistanceTime, Speed, and Distance Relationships on Dry, Clean SurfacesRelationships on Dry, Clean Surfaces

30 mph 44 f/s 88 ft. 132 ft. 176 ft. 22 ft. 33 ft. 80 ft.

40 mph 58 f/s 116 ft. 174 ft. 232 ft. 29 ft. 44 ft. 125 ft.

50 mph 74 f/s 148 ft. 222 ft. 296 ft. 37 ft. 56 ft. 190 ft.

60 mph 88 f/s 176 ft. 264 ft. 352 ft. 44 ft. 66 ft. 275 ft.

70 mph 104 f/s 208 ft. 312 ft. 416 ft. 52 ft. 78 ft. 385 ft.

Following Intervals

2 Seconds… Permits driver time to steer out of problem areas at all listed speeds on a dry surface and braking out of problems at speeds under 35 mph.

3 Seconds… Permits driver time to steer out of problem areas at all listed speeds on dry surface and braking out of problems at speeds to 45 mph.

4 Seconds… Permits driver to steer out of problems at all listed speeds on dry surface and braking out of problems at speeds to legal limit of 65 mph.

* Factory equipped passenger car tires may not be designed to steer out of problem areas at speeds beyond 75 mph. Speed rated tires are required due to sidewall flexion problems at higher speeds and turning movements.

Importance of Good VisionDistance Vision-Ability to see far down the road 20-30 seconds

Depth Perception Helps you control your following distance and lets you

adjust your position in traffic, change lanes, pass, pull into traffic

To compensate for poor depth perception-Increase following distance

Color Vision Drivers must recognize colors in objects (signs, signals,

etc.) Can color Bind people drive ? (Shape, Shade, or position)

Vision ProblemsContrast Sensitivity- Helps you see details in the driving environment

Night Vision Good night vision requires an ability to see in low and variable light

conditions Reduced visibility at night due to dirty windshield, headlights, rain, etc.

Glare Vision- Ability to see when there is rapid increase in light Headlights Sun Snow Rain

Glare Recovery- Caused by the sudden brightness of oncoming headlights

1.Do not look directly into headlights Reduce speed Be aware on hills and curves

Assessment1. What are the 4 types of Vision? List and Explain.2. If your focus vision is on the target at the end of the path of travel, which vision will allow the driver to see the placement of vehicle in the roadway.3. What three things will occur when you increase your speed?4. Increased line of sight and path of travel will lead to what three things to occur?5.Explain following distance.6.What is considered a safe following distance?7. At what speed (s) do you still have time to steer out of problems if you are following at 2 seconds?8. What is the three factors for having good vision?9. How do color blind drivers determine the color of traffic lights?10. What is Glare Recovery, and how can a driver compensate for this problem? 11. What are the ways items we can identify to help us determine that we have control of our risk?12. What are the three zones that involve time and space, and are important to our path of travel?