Historically, a suicide lane has referred to a lane in the center of a highway meant for passing in both directions. Neither direction had right-of-way, and head-on accidents were common. Very few of these setups are left, at least in the United States, though sometimes a similar layout exists, where three lanes are striped with two in one direction and one in the other, but traffic in the direction with one lane is allowed to cross the centerline to pass. However, this is nowhere near as dangerous, because one direction has clear right-of-way.

Nowadays, the term usually refers to a center left-turn lane (for countries which drive on the right), a single lane in the center of the road into which traffic from both directions pulls to make a left turn. It is also used by drivers turning left onto the main road, though this practice is often illegal.

These roads are very common in suburban areas, and rather less common in rural areas.

Oddities

• Ontario Provincial Highway 17 has a railroad on the north side in Sault Ste. Marie, Ontario; the center lane on this corridor is restricted to westbound traffic. A double-yellow solid line separates the eastbound through lanes and the center lane.
• Rand McNally posts many 5-lane arterials in the countryside as divided highways on their maps.