Pavement markings

Key points

1. A dashed yellow line means vehicles in either lane can cross it when safe.

   Source: Handbook p. 58

   “A dashed yellow line means that vehicles in either lane can cross the line if it is safe to do so.”
   Idaho Driver's Handbook, Handbook p. 58

2. Double solid yellow lines mean no passing, but you may cross them to turn left into or out of a driveway.

   Source: Handbook p. 58

   “A driver can cross a double yellow line when turning left into or out of a driveway or entrance to a business. No passing is allowed.”
   Idaho Driver's Handbook, Handbook p. 58

3. With a solid and a dashed yellow line, only vehicles on the dashed side may cross to pass.

   Source: Handbook p. 58

   “One solid yellow line and one dashed yellow line means that only vehicles in the lane with the dashed line (lower lane in this drawing) can cross the lines to pass other vehicles.”
   Idaho Driver's Handbook, Handbook p. 58

4. Shared center lanes are for left turns and permitted U turns from either direction.

   Source: Handbook p. 58

   “Center lanes are reserved for making left turns (or U-turns when they are permitted) from either direction of travel.”
   Idaho Driver's Handbook, Handbook p. 58

5. Avoid changing lanes where a solid white line separates lanes going the same direction.

   Source: Handbook p. 59

   “Avoid changing lanes where a solid white line separates lanes of traffic moving in the same direction.”
   Idaho Driver's Handbook, Handbook p. 59

6. Double solid white lines prohibit lane changes.

   Source: Handbook p. 59

   “Lane changes are prohibited in areas where this type of marking is present.”
   Idaho Driver's Handbook, Handbook p. 59

7. Never straddle dashed white lane lines; cross only when it is safe to change lanes.

   Source: Handbook p. 59

   “Drive within these lines. Never straddle them. Cross over them only when it is safe to change lanes.”
   Idaho Driver's Handbook, Handbook p. 59

8. At dashed bike lane lines, if a bike is already in that area, right turning drivers must yield.

   Source: Handbook p. 60

   “if a bike is already in that area, right turning drivers must yield.”
   Idaho Driver's Handbook, Handbook p. 60

3 questions from the Idaho practice test

1. 1. When a solid yellow line is paired with a dashed yellow line, which traffic may cross to pass?

   1. Traffic in either lane whenever the road is straight
   2. Only traffic in the lane beside the dashed line
   3. Only traffic beside the solid line
   4. Neither lane, except for a legal U-turn
   Show answer

   Only traffic in the lane beside the dashed line. A solid yellow line beside a dashed yellow line divides the passing permissions by lane. Only vehicles traveling in the lane next to the dashed line may cross the markings to pass, and they still must confirm that the maneuver is safe. The lane beside the solid line cannot cross to pass. A straight road does not erase the marking, and the rule is about passing rather than granting a general U-turn exception. Identify which side contains the dashed line before considering any crossing movement.

2. 2. On a two-way Idaho road, what does a pair of solid yellow center lines mean?

   1. The lines mark a center turn lane that may be used for extended travel
   2. Passing is permitted for traffic traveling in both directions
   3. Only vehicles next to the left line may pass slower traffic
   4. Passing is prohibited, although a driver may cross safely to turn into a driveway
   Show answer

   Passing is prohibited, although a driver may cross safely to turn into a driveway. Two solid yellow lines separate opposing traffic where passing is not allowed. The handbook makes a narrow distinction: a driver may cross the lines when it is safe to turn left into or out of a driveway or business entrance. That exception is a turning movement, not permission to overtake. A dashed line would allow a safe crossing for passing, and the shared center lane has a different marking pattern. Treat the double solid lines as a no-passing warning, then wait for a legal, visible opportunity elsewhere.

3. 3. What is the recommended action when a solid white line separates lanes moving in the same direction?

   1. Change lanes across it whenever the adjacent lane is empty
   2. Cross it immediately when traffic behind you is close
   3. Treat it as a centerline between opposing traffic
   4. Avoid changing lanes where a solid white line separates same-direction traffic
   Show answer

   Avoid changing lanes where a solid white line separates same-direction traffic. A solid white lane line separates traffic traveling the same way and signals that a lane change should be avoided at that location. It is not a yellow centerline, so the opposing-direction choice misreads its purpose. Crossing it immediately is the opposite of the handbook’s guidance, and stopping on the paint creates an unnecessary hazard. Continue within your lane until the marking permits a suitable change, then check mirrors and the blind spot before moving. The visual cue is simple: solid white means hold your lane unless another instruction clearly applies.

Source: the Idaho Driver's Handbook, Highway & Vehicle Knowledge. 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.