In Illinois, when are headlights required to be turned on?

In Illinois, headlights are required to be turned on from sunset to sunrise, as well as during conditions where visibility is less than 1,000 feet. This regulation ensures that drivers can see and be seen in low-light or poor visibility situations, such as at night or during inclement weather like rain, fog, or snow. Proper use of headlights significantly enhances safety by improving visibility for both the driver and other road users. Keeping headlights on during these times reduces the risk of accidents that can occur due to inadequate visibility.

The other options do not encompass the full range of circumstances under which headlights should be used. For example, only requiring headlights during the day or solely in rainy conditions neglects important visibility factors, while saying they should be on whenever the engine is running doesn't account for the nuances necessary for safe driving during varied lighting conditions.