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？
  Q( V" s) E: _9 n谢谢！

EightBelow

U-turns
• Do not make a U-turn unless you can do it safely and without interfering
5 R6 h( y- [  l1 e2 u( s/ Q; {2 ~+ Z) Ewith other traffic.
  [" o5 [+ V1 t. M• Outside urban areas U-turns are not permitted on a curve or near the
crest of a hill where the driver of another vehicle cannot see your vehicle.
! A6 ]& Z9 v3 u7 wU-turns are not permitted in urban areas in the following situations:
• On a roadway between intersections.
: u! I# q* @9 ]  D2 H2 H• Where a sign prohibits making a U-turn.
/ x8 K& `3 r. y( D8 d' B# C• At an intersection controlled by a traffic-control signal (traffic lights).
. ~# v$ n5 P9 _; K+ W) W• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。