A 3-minute lesson from the Idaho course. Read the rules and examples, follow the handbook page references, and check your understanding before you move on.
Idaho's traffic laws are the 'Rules of the Road' for stopping, speed, yielding, passing, and parking. Speed comes first: posted limits are maximums for ideal conditions, and the basic rule can make a slower speed the legal one.
Basic rule
Idaho law requires you to drive at a speed that is 'reasonable and prudent' at all times, on every road, even where maximum and minimum limits are set by law or posted.
It is illegal to drive so slowly that you disrupt the normal flow of traffic. You may not stay in the extreme left-hand lane long enough to impede traffic moving at a lawful speed.
The posted limit is 65 mph but the highway is covered in packed snow and you can barely see. Driving 65 would break the basic rule. Slow to a speed that is reasonable and prudent for the ice and visibility.
Check your understanding
Read the question, decide on an answer, then open it to check the explanation. These are Roadwise study questions based on the source handbook.
Idaho's 'basic rule' requires you to drive at a speed that is:
at least 5 mph under the limit
reasonable and prudent
always the posted limit exactly
never below the posted limit
Answer: reasonable and prudent
The basic rule requires reasonable and prudent speed regardless of the posted limit.
