Unit: Two Topic: A7 Thru A9
(Please Listen to Narration or read the Paragraphs below )

A7. Vision, night vision.

Night vision refers to your ability to see well in low light levels and is necessary for being able to drive safely at night.

The visual ability of two drivers may be about the same during daylight hours, but be markedly different at night.

Driving safely at night requires seeing well not only under low illumination, but also requires being able to see low contrast objects. A person wearing dark clothing and crossing the street in front of a driver is much harder to detect at night because there is much less contrast at night between the darkly-clothed pedestrian and the dark background.

Poor night vision while driving at night can result (a) in not being able to react to hazards in front of your vehicle in a timely manner, (b) tailgating, (c) failing to steer in the proper direction when necessary to avoid low-contrast road features such as the edges of the roadway and (d) other irregularities in the road surface.

A8. Vision, glare resistance and recovery.

Glare is intense and blinding light. For example, glare caused by the brightness of oncoming headlights can prevent a driver from seeing an approaching vehicle or pedestrian crossing the roadway.

Glare resistance is the extent to which a driver can still see objects and events while facing a steady source of glare such as the setting sun or the light from oncoming headlights.

Glare recovery is the speed with which a driver's vision returns to normal after being exposed to glare.

Glare resistance and recovery are important for being able to drive safely during sunset or at night.

Glare resistance and recovery deteriorate with age; older drivers must drive more cautiously at night.

Poor glare resistance and recovery can result in a driver being blinded by a glare source and (a) missing curves in the road, (b) striking unobserved pedestrians, and (c) crashing into the rear of a slow-moving, stalled, or stopped vehicle.

A9. Vision, color blindness.

Color blindness is the inability to accurately and consistently distinguish between certain colors such as those at traffic lights and on signs, and if severe, may affect your ability to drive safely.