Driver's License Test Prep
Oregon Practice Vehicle Equipment

When Oregon law requires you to dim your high beams, what must you also do with your fog lights or other auxiliary lights?

  1. A.
    Leave them on: fog lights are exempt from the dimming rule.
  2. B.
    Turn them off when required to dim your headlights. Correct
  3. C.
    Leave them on if they are amber-colored fog lights.
  4. D.
    Use them as a substitute for your dimmed high beams.
The Why

The answer is "Turn them off when required to dim your headlights."

When you are required to dim your headlights, other auxiliary lights such as fog lights must also be off. The dimming triggers are oncoming traffic within 500 feet and following another vehicle within 350 feet; whenever either applies, the auxiliary lights come off too. Fog lights and similar extras throw wide, low scatter that creates glare for oncoming drivers, which is exactly what dimming is meant to prevent.

Why the others miss

The traps in the wrong answers

A. Leave them on: fog lights are exempt from the dimming rule.

The manual is explicit that fog lights and other auxiliary lights must be off when you are required to dim. There is no fog-light exemption. Misreading: Treats fog lights as a blanket exception, contradicting the manual's rule that auxiliary lights must be off when dimming.

C. Leave them on if they are amber-colored fog lights.

The rule applies to fog lights and other auxiliary lights regardless of bulb color; nothing in the manual creates a color-based exemption. Misreading: Invents a color-based exemption not in the manual; the off requirement applies to auxiliary lights regardless of their color.

D. Use them as a substitute for your dimmed high beams.

The manual requires auxiliary lights to be off when you dim; they are not a substitute for high beams. Extra lights make it difficult for oncoming drivers to see. Misreading: Reads the rule as permitting fog lights to replace dimmed high beams, when the manual actually requires those auxiliary lights to be off.

The Rule

This question tests your knowledge of Vehicle Equipment in Oregon. Source: Oregon Driver Manual, "Using Lights," p.76..

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