Missouri Laws 300.215 – Required position and method of turning at intersection
The driver of a vehicle intending to turn at an intersection shall do so as follows:
(1) Right turns: Both the approach for a right turn and a right turn shall be made as close as practicable to the right-hand curb or edge of the roadway, except where multiple turn lanes have been established.
(2) Left turns on two-way roadways: At any intersection where traffic is permitted to move in both directions on each roadway entering the intersection, an approach for a left turn shall be made in that portion of the right half of the roadway nearest the center line thereof and by passing to the right of such center line where it enters the intersection and after entering the intersection the left turn shall be made so as to leave the intersection to the right of the center line of the roadway being entered. Whenever practicable the left turn shall be made in that portion of the intersection to the left of the center of the intersection.
(3) Left turns on other than two-road roadways: At any intersection where traffic is restricted to one direction on one or more of the roadways, the driver of a vehicle intending to turn left at any such intersection shall approach the intersection in the extreme left-hand lane lawfully available to traffic moving in the direction of travel of such vehicle and after entering the intersection the left turn shall be made so as to leave the intersection, as nearly as practicable, in the left-hand lane lawfully available to traffic moving in such direction upon the roadway being entered, except where multiple turn lanes have been established.
(4) Designated two-way left turn lanes: Where a special lane for making left turns by drivers proceeding in opposite directions have been indicated by official traffic control devices:
(a) A left turn shall not be made from any other lane;
(b) A vehicle shall not be driven in the lane except when preparing for or making a left turn from or into the roadway or when preparing for or making a u-turn when otherwise permitted by law;
(c) A vehicle shall not be driven in the lane for a distance more than five hundred feet.