Final answer:
The distance at which you should dim your highbeam headlights when an oncoming vehicle approaches is within 500 feet.
Step-by-step explanation:
The distance at which you should dim your highbeam headlights when an oncoming vehicle approaches can vary, but a general guideline is within 500 feet. The exact distance may depend on factors such as the brightness of the oncoming vehicle's headlights and road conditions. Dimming your highbeams helps prevent blinding the other driver, ensuring safe and clear visibility for both parties.