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？
) C2 D" G! R* P% o! r; {  p谢谢！

EightBelow

U-turns
• Do not make a U-turn unless you can do it safely and without interfering
with other traffic.
/ w, r4 p' i6 [' {- I• 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:
0 M) [6 X: o. Q& q• On a roadway between intersections.
) ?; r0 f" W5 j1 e9 a9 z• Where a sign prohibits making a U-turn.
7 }$ x; |2 y. c) k' X5 H• At an intersection controlled by a traffic-control signal (traffic lights).
' j+ l% M; J' i4 j$ l3 ?( T• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。