When driving at 60 mph, a driver's field of vision is:
- Two-thirds of what it is when the vehicle is stationary.
- One-fifth of what it is when the vehicle is stationary. ✓
- Three-fifths of what it is when the vehicle is stationary.
- Four-fifths of what it is when the vehicle is stationary.
Answer: B. One-fifth of what it is when the vehicle is stationary.
At 60 mph, a driver's field of vision is about one-fifth of what it is when the vehicle is stationary.
Why this is the answer
The handbook's speed-and-vision chart starts with a stationary field of 180 degrees or more and shows it narrowing as speed rises. At 20 mph it is about two-thirds, at 40 mph about two-fifths, and at 60 mph about one-fifth. That direct chart entry supports choosing the one-fifth description. The larger fractions belong to lower speeds in the same chart, not to 60 mph.
Why the other answers are wrong
- A. Two-thirds of what it is when the vehicle is stationary. — Two-thirds is the handbook's figure for 20 mph, not for 60 mph.
- C. Three-fifths of what it is when the vehicle is stationary. — The chart gives about two-fifths at 40 mph, not three-fifths, and it does not assign three-fifths to 60 mph.
- D. Four-fifths of what it is when the vehicle is stationary. — Four-fifths does not appear in the handbook's speed-and-vision chart; at 60 mph the listed figure is about one-fifth.
Remember it
Picture the fractions falling as speed climbs: two-thirds at 20, two-fifths at 40, one-fifth at 60.