Driver's License Test Prep
US Road Signs Road Markings

An extra-wide solid white line runs along the right side of the roadway. What does it tell you as a driver?

A single extra-wide solid white line running lengthwise along the lower edge of a dark roadway.
  1. A.
    Keep the line on your left and stay off the shoulder. Correct
  2. B.
    Cross the line to pass slower traffic on the right.
  3. C.
    Stop your vehicle before crossing the line ahead.
  4. D.
    The lane is reserved for bicycles only.
The Why

The answer is "Keep the line on your left and stay off the shoulder."

An extra-wide solid white edge line marks where the travel lane ends on the right, and the driver keeps it on the left while treating the shoulder beyond it as off-limits for normal driving. The tempting wrong choice reads the line as a broken lane divider that a driver may cross to move right, a rule that belongs to dashed white lines between two through lanes, not to an edge line whose whole job is to mark the outer boundary of the lane you are already in.

Why the others miss

The traps in the wrong answers

B. Cross the line to pass slower traffic on the right.

The line marks the outer edge of the travel lane, not a divider between two through lanes, so crossing it puts a vehicle on the shoulder rather than into a lawful passing lane. This answer borrows the rule for passing on a multi-lane highway where broken white lines let a driver change lanes.

C. Stop your vehicle before crossing the line ahead.

The line runs lengthwise along the right side of the roadway in the direction of travel, not across it, and an edge line carries no requirement to stop. This answer reaches for the stop-line rule out of habit whenever a solid white line appears near the roadside.

D. The lane is reserved for bicycles only.

A wide edge line marks the outer boundary of the general travel lane, and a bike-only lane would be identified by a bicycle symbol painted inside the lane itself. This answer takes the extra width of the line as a signal that the lane it borders is set aside for cyclists.

The Rule

This question tests your knowledge of Road Markings on the roads of every US state . Source: Manual on Uniform Traffic Control Devices, marking 3B.06 (Wide Solid White Edge Line)..

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