Why is keeping to the right except when passing common on multilane highways?

• A. It helps maintain smooth traffic flow and reduces weaving.
• B. Reduces fuel efficiency.
• C. It confuses other drivers.
• D. It is illegal in all cases.

Answer: (A)

Keeping to the right except when passing on multilane highways helps traffic move smoothly and predictably. When most drivers stay in the right lanes, speeds stay more consistent and fewer lane changes occur, which cuts down on weaving and the conflicts that happen when drivers continually try to find faster gaps. The left lane is then available for those who need to pass, or for preparing to exit, without interrupting the through traffic in the right lanes. This arrangement reduces sudden braking, bottlenecks, and crashes caused by frequent lane shifts, making the overall flow safer and more efficient.

The other ideas don’t fit. Staying in the right doesn’t reduce fuel efficiency; in fact, steadier speeds with fewer lane changes can save fuel. It doesn’t confuse other drivers, since a consistent pattern helps drivers anticipate what others will do. And it isn’t illegal in all cases—many places permit the left lane to be used for passing, but require keeping the right lanes for regular through traffic unless you’re actively passing.