Final answer:
Drivers should typically dim their headlights when an oncoming vehicle is within 500 feet. This rule ensures that the oncoming driver is not blinded, thus maintaining road safety.
Step-by-step explanation:
The question of how many feet you should dim headlights for oncoming traffic is oriented around driving safety and regulations. While the exact distance can vary by jurisdiction, a common rule is to dim your headlights when an oncoming vehicle is within 500 feet. This is a safety precaution to prevent blinding the oncoming driver, which could result in an accident. Understanding the distance at which car headlights are visible, in various conditions, illustrates why this rule is essential for road safety. Additionally, it's important to note the inverse square law of illuminance, which indicates that light intensity diminishes with the square of the distance from the source, further highlighting the necessity of dimming headlights to maintain visibility for all drivers.