Dedicated left-turn lane (Provided photo — Dave Werner)

Last week’s column dealt with the proper use of a two-way left-turn (TWLT) lane, also often called a center turn lane. Today’s column is about the proper way to use a dedicated left-turn lane, as in the accompanying picture.

A left-turn-only lane is a lane that is dedicated to left-turning vehicles. It is marked with pavement markings and, if at a signalized intersection, a “left turn only” sign, telling drivers that they are only allowed to travel in the direction of the arrow.

Often a dedicated left-turn lane is preceded by a TWLT lane that changes to a left-turn-only lane prior to the intersection for which it is intended. The change is where the yellow lines on the right side of the TWLT lane end, followed by a gap or a dotted white line before it changes to a solid white line. (See picture.) Double arrows on the pavement that mark the TWLT lane change to a single left-turn arrow in the left-turn-only lane, meaning you must turn left from that lane. Often the word “only” supplements the left-turn arrows.

The proper place to enter a left-turn lane is where the gap or dotted white lines are located. Although there is no standard distance for the length of the gap or the left-turn lane, depending on geometrics, expected traffic in the queue, etc., there is always plenty of room to enter the turning lane where the gap is.

Many drivers wrongly enter the TWLT lane before it becomes a left-turn-only lane. If you intend to turn left and there is a left-turn-only lane for your turn, you should not enter it before the gap.

Furthermore, you must signal your lane change at least 100 feet prior to entering the turn lane.

Left-turn lanes are important to safe, efficient traffic movement, but only if utilized correctly.