Regulatory Signs
Regulatory Signs are the white rectangular signs with black or red legends that create legal requirements. This domain tests whether you can read the specific rule, identify who and when it applies, and separate a regulation from a warning or guide sign. Oregon speed-limit signs set the maximum lawful speed under current conditions; they do not require you to drive that fast. Stop signs require a full stop at the stop bar or before the crosswalk, and yield signs require you to slow and give way. Lane-use signs such as LEFT TURN ONLY or STRAIGHT OR RIGHT assign movements by lane. Turning signs can prohibit a movement outright or by time and vehicle class, and parking signs control standing, stopping, or parking on a defined curb segment.
Worked example
A sign reads NO LEFT TURN 7-9 AM MON-FRI. You approach at 8:15 AM on Tuesday and want to turn left. The day and time fall inside the restriction, so the turn is prohibited; the sign is not merely advisory. If the sign said NO LEFT TURN with a red circle and slash, the prohibition would apply at all times unless a supplementary plaque says otherwise.
Traps
Do not treat a speed limit as a target or a warning sign as law. Check the entire sign assembly: an arrow, time plate, or EXCEPT plaque changes the rule. NO PARKING and NO STOPPING are different. A right turn on red is generally allowed in Oregon after a full stop unless a sign prohibits it, but you must still yield to pedestrians and traffic.