The Basic Rule and Variable Speed Signs

Key points

1. The basic rule says drive at a speed reasonable and cautious for existing conditions, on all roads at all times.

   Source: Handbook p. 20

   “The basic rule states you must drive at a speed that is reasonable and cautious for existing conditions. The basic rule applies on all roads at all times.”
   Oregon Driver Manual, Handbook p. 20

2. Driving too fast for conditions breaks the basic rule even below the speed limit.

   Source: Handbook p. 21

   “If you drive at a speed that is unsafe for existing conditions in any area, at any time, even if it is slower than the speed limit, you are violating the basic rule.”
   Oregon Driver Manual, Handbook p. 21

3. The basic rule never lets you drive over the speed limit.

   Source: Handbook p. 21

   “The basic rule does not allow you to drive over the speed limit.”
   Oregon Driver Manual, Handbook p. 21

4. Yellow variable advisory speed signs recommend a speed; they are not limits, but police may enforce them through the basic rule.

   Source: Handbook p. 20

   “These are not speed limits, but police may enforce them through the basic rule law.”
   Oregon Driver Manual, Handbook p. 20

5. Black and white variable speed limit signs change the limit and are enforced like any speed limit sign.

   Source: Handbook p. 20

   “Police may enforce these signs like any other speed limit sign.”
   Oregon Driver Manual, Handbook p. 20

6. If you drive slower than traffic, use the right lane or stay near the right edge unless turning left.

   Source: Handbook p. 21

   “If you drive slower than the normal speed of traffic, you must use the right lane or drive as closely as possible to the right curb or edge of the road”
   Oregon Driver Manual, Handbook p. 21

7. Racing on any road is illegal.

   Source: Handbook p. 21

   “It is illegal to race on any road.”
   Oregon Driver Manual, Handbook p. 21

3 questions from the Oregon practice test

1. 1. What does Oregon's basic rule require when choosing a driving speed?

   1. The speed of the fastest nearby vehicle
   2. The posted maximum in every circumstance
   3. A speed reasonable and cautious for existing conditions
   4. A speed five miles below the sign
   Show answer

   A speed reasonable and cautious for existing conditions. Oregon's basic rule requires a speed that is reasonable and cautious for existing conditions. A posted maximum is not a command to drive that fast when weather, visibility, traffic, pedestrians, or the road surface call for less. Matching the fastest vehicle can create an unsafe pace, and the manual does not establish a universal five-mph reduction. The cue is conditions first: evaluate what is happening around the vehicle, then stay at or below the applicable maximum while choosing a safe speed.

2. 2. What is the legal status of an Oregon variable advisory speed sign?

   1. It recommends a speed based on current conditions
   2. It permanently replaces every posted speed limit
   3. It permits travel above the statutory maximum
   4. It applies only when a police officer is present
   Show answer

   It recommends a speed based on current conditions. A variable advisory speed sign recommends a speed for conditions such as heavy traffic, poor weather, or a slippery road. The manual distinguishes that recommendation from a variable speed limit sign, which changes the legal limit and can be enforced like another speed limit sign. An advisory display does not replace every permanent limit or authorize travel above a maximum. Police may still enforce the basic rule, so the driver should choose a reasonable and cautious speed for the conditions shown.

3. 3. When driving slower than the normal flow of traffic in Oregon, where should you drive?

   1. In the right lane or as close as possible to the right curb or edge
   2. In the left lane to make faster traffic pass on the shoulder
   3. On the center line so both lanes remain visible
   4. In whichever lane has the highest posted limit
   Show answer

   In the right lane or as close as possible to the right curb or edge. A driver traveling slower than normal traffic must use the right lane or drive as close as possible to the right curb or edge, unless preparing for a left turn. The left lane choice interferes with faster traffic and does not authorize shoulder travel. The center line is not a lane for ordinary slow travel, and lane selection is not based on finding a higher posted limit. Watch for congestion building behind you, then pull off at the first safe area when needed to let traffic pass.

Source: the Oregon Driver Manual, Lane Travel: Speed Regulations. This lesson is a plain English summary, not the law itself; where it differs, the manual and the statute govern. Last checked 2026-09-27.