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
& F" }; {" ]6 g( `- A• Do not make a U-turn unless you can do it safely and without interfering
6 c) D/ w+ r3 K* f9 lwith other traffic.
2 k* n, J+ K& @' B: m. k' ?• Outside urban areas U-turns are not permitted on a curve or near the
2 r5 ~% C5 [  X4 a8 g1 z, ~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.
) x( o6 k% r0 W) g" m; H• Where a sign prohibits making a U-turn.
• At an intersection controlled by a traffic-control signal (traffic lights).
8 O2 I- a8 e& |- @3 t+ ^" n, o• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。