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？
' ^( T9 m" P3 O, k& D& t谢谢！

EightBelow

U-turns
• Do not make a U-turn unless you can do it safely and without interfering
with other traffic.
' ?! g. \9 [- k6 u0 J• Outside urban areas U-turns are not permitted on a curve or near the
6 D4 l( Z  Q  d, }/ a" g( Ocrest of a hill where the driver of another vehicle cannot see your vehicle.
8 F  X6 c% f& l$ @+ d1 _" BU-turns are not permitted in urban areas in the following situations:
• On a roadway between intersections.
) A7 T* d  C7 E, `9 `) f5 E% u• Where a sign prohibits making a U-turn.
• At an intersection controlled by a traffic-control signal (traffic lights).
5 S7 e4 n) V  g- v• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。