What height is the recommended object visibility for assessing sight distance in driving?

The recommended object visibility height for assessing sight distance in driving is generally considered to be around 3.5 to 4.5 feet. This height approximates the eye level of an average driver in a vehicle. Drivers are typically seated at this height, which makes it essential for sight distance assessments to be based on an object (like a sign or an obstacle) visible at that elevation.

Since the correct choice is not accurately identified as the recommended visibility height, the correct value should align more closely with the standard pedestrian or driver eye level, usually around 3.5 feet. The choice of 6 inches would be too low as it does not represent the average driving perspective, which means it wouldn’t provide an accurate measure for sight distance assessments.

Contextually, using a value that reflects an accurate eye level ensures that visibility and sight distance can be appropriately evaluated for safety and operational efficiency on roadways. Thus, the choice representing 3 feet would be the most acceptable regarding driver visibility, aligning closely with standard practices.