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？
8 T. o( o4 p4 Z. {) ^+ X0 R7 s5 s谢谢！

EightBelow

U-turns
• Do not make a U-turn unless you can do it safely and without interfering
5 T9 @6 c8 N8 L1 {' T6 n- i7 qwith other traffic.
• Outside urban areas U-turns are not permitted on a curve or near the
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.
6 r( D  c3 m3 t* `& Z! B• Where a sign prohibits making a U-turn.
8 W; d& o( X+ [( \! y( D" 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。