Driver's License Test Prep
Oregon Practice Speed Limits

You're driving 50 mph on an Oregon road posted at 55 mph during a heavy fog. Visibility is only about 200 feet. Which is true?

  1. A.
    You can only be ticketed if you cause a crash.
  2. B.
    You can be cited under the basic rule for driving at a speed unsafe for current conditions. Correct
  3. C.
    You should turn on your high beams to see better and continue at 50 mph.
  4. D.
    You cannot be ticketed because you are below the posted limit.
The Why

The answer is "You can be cited under the basic rule for driving at a speed unsafe for current conditions."

Even when you are below the posted 55 mph limit, you can be cited under the basic rule for driving at a speed unsafe for existing conditions. Heavy fog with 200-foot visibility almost certainly demands slower than 50 mph. The basic rule applies on all roads at all times, regardless of the posted limit. Drivers drawn to D read the posted number as a safe-harbor floor, but the manual makes clear the basic rule still governs at any speed the conditions make unsafe.

Why the others miss

The traps in the wrong answers

A. You can only be ticketed if you cause a crash.

A crash is not required for a basic-rule citation. This answer adds a collision precondition the manual does not impose; the basic rule applies on all roads at all times based on conditions, not on whether a crash occurred.

C. You should turn on your high beams to see better and continue at 50 mph.

Wrong on two counts: high beams reflect off fog and reduce visibility (low beams are required), and the 50 mph speed remains unsafe regardless of headlight choice. This answer inverts the manual's fog-driving guidance, which directs drivers to use headlights on low beam in fog because high-beam light reflects back and makes it harder to see ahead.

D. You cannot be ticketed because you are below the posted limit.

The basic rule allows enforcement even at speeds below the posted limit when conditions are unsafe. This answer treats the posted speed limit as a safe-harbor floor; the manual states the basic rule still applies even when you are slower than the speed limit.

The Rule

This question tests your knowledge of Speed Limits in Oregon. Source: Oregon Driver Manual, "The Basic Rule Law," p.21..

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