在加州

 (b) Left Turns. The approach for a left turn shall be made as
close as practicable to the left-hand edge of the extreme left-hand
lane or portion of the roadway lawfully available to traffic moving
in the direction of travel of the vehicle and, when turning at an
intersection, the left turn shall not be made before entering the
intersection. After entering the intersection, the left turn shall be
made so as to leave the intersection in a lane lawfully available to
traffic moving in that direction upon the roadway being entered,
except that upon a highway having three marked lanes for traffic
moving in one direction that terminates at an intersecting highway
accommodating traffic in both directions, the driver of a vehicle in
the middle lane may turn left into any lane lawfully available to
traffic moving in that direction upon the roadway being entered.

http://www.leginfo.ca.gov/cgi-bin/displaycode?section=veh&group=22001-23000&file=22100-22113