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- d/ G6 X2 [4 u! ]$ B0 Z% q% b- ?• Do not make a U-turn unless you can do it safely and without interfering
2 `+ N1 w/ q2 W5 T% Ewith other traffic.
• Outside urban areas U-turns are not permitted on a curve or near the
  e( N* v8 H  {/ U6 X* R  p, l4 b3 f2 ]crest of a hill where the driver of another vehicle cannot see your vehicle.
U-turns are not permitted in urban areas in the following situations:
• On a roadway between intersections.
+ s+ G3 u6 K! D• Where a sign prohibits making a U-turn.
/ W0 ^0 G/ a) }1 V• At an intersection controlled by a traffic-control signal (traffic lights).
• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。