Final answer:
You must dip your headlights at least 200 metres before approaching another vehicle at night as a common roadway safety requirement, but local regulations can vary.
Step-by-step explanation:
You are driving towards another vehicle at night, and you must 'dip' your headlights before getting too close to the other vehicle to avoid dazzling the driver. While this question does not directly relate to the physics concepts provided for resolution and diffraction of light, it is a safety regulation that typically dictates headlight usage. Rules may vary by jurisdiction, but a common requirement is to dim your headlights within 200 metres of an oncoming vehicle or when following another vehicle within 200 metres. It is essential to check your local road safety regulations for the most specific rule applicable to your area.