有关u-turn

小胡同

最近查google map for directions, 经常会看到需要u-turn。印象之中好像在主路上不可以，不管是否有不可u-turn的牌子。平常也看到有人在红绿灯处做u-turn。
请问u-turn到底是不是合法的？
谢谢！

EightBelow

U-turns
# G  Q9 p+ x; D! y" o• Do not make a U-turn unless you can do it safely and without interfering
with other traffic.
: ~, B9 g( J  v% C. s• Outside urban areas U-turns are not permitted on a curve or near the
$ L) N3 w! x! W1 L9 p& b4 F* rcrest of a hill where the driver of another vehicle cannot see your vehicle.
# w: p5 Y$ Y- X. ?U-turns are not permitted in urban areas in the following situations:
• On a roadway between intersections.
6 ]. I6 U. r5 i: P* x' H7 k# n) Z& k• Where a sign prohibits making a U-turn.
; ^3 g1 Z9 g2 [3 g• At an intersection controlled by a traffic-control signal (traffic lights).
  }8 b  s# n. [! d• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。