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
• Do not make a U-turn unless you can do it safely and without interfering
! P- i7 r) |6 h& m2 l# p0 mwith other traffic.
• Outside urban areas U-turns are not permitted on a curve or near the
. C' W6 v% Q+ X* Gcrest of a hill where the driver of another vehicle cannot see your vehicle.
+ g1 t# N3 a7 `U-turns are not permitted in urban areas in the following situations:
. ?' o' q: R/ E  p. l! Z• On a roadway between intersections.
+ e1 L: k9 W4 P; l1 u/ u9 N" y• Where a sign prohibits making a U-turn.
• At an intersection controlled by a traffic-control signal (traffic lights).
2 W. @- d# i1 w• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。