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？
4 p* i0 G) g2 f  P1 a谢谢！

EightBelow

U-turns
• Do not make a U-turn unless you can do it safely and without interfering
with other traffic.
. v$ O( ^$ k" P( ~' i. h5 W, b6 M) |! H+ n• Outside urban areas U-turns are not permitted on a curve or near the
0 N1 c& ^' N% y3 a) }5 S6 `crest of a hill where the driver of another vehicle cannot see your vehicle.
  L4 S( H* U9 Y4 b: ~U-turns are not permitted in urban areas in the following situations:
• On a roadway between intersections.
0 p- n4 c* q7 [. O, ?• Where a sign prohibits making a U-turn.
• At an intersection controlled by a traffic-control signal (traffic lights).
: \$ P5 M  ?9 K+ x• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。