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？
$ i% C2 P- l4 K7 m谢谢！

EightBelow

U-turns
• Do not make a U-turn unless you can do it safely and without interfering
+ x! W/ q/ e6 O5 Z: j& pwith other traffic.
9 [* e9 n  [1 I• Outside urban areas U-turns are not permitted on a curve or near the
0 R( H. B$ `/ K4 Q; Bcrest 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:
: D, i1 s2 [3 m• On a roadway between intersections.
+ A, D$ h) k8 F" S0 w7 M• Where a sign prohibits making a U-turn.
9 L1 [4 ~5 _3 C. Q• At an intersection controlled by a traffic-control signal (traffic lights).
' x2 R; y  ]9 T• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。