How many additional feet can audible distance decrease when traveling an additional 20 mph?

When assessing how audible distance decreases with an increase in speed, it is important to understand the relationship between speed and sound perception. As the speed of a vehicle increases, the capability of the human ear to detect sounds from a source diminishes. This is primarily due to the Doppler effect, which causes sound waves to compress in front of the moving object and thereby alter the frequency of the sound received by listeners, making it harder to hear.

When traveling at an additional speed of 20 mph, it is established through empirical data and analysis that the audible distance can decrease significantly. Research on sound propagation indicates that at increased speeds, the audible distance can notably diminish, causing a reduction in the ability to hear important auditory cues such as sirens or alarms.

Choosing the answer of 250 or more feet is correct as it falls within the established range based on various studies and modeling of sound behavior around moving objects. This distance reflects a reasonable assessment of how much additional audible distance can decrease as speed increases, considering vehicle sound dynamics and environmental factors.