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？
) t) Y5 h8 @: u5 D# w$ m2 s! c* R谢谢！

EightBelow

U-turns
2 p. g, u: l4 K( N2 R7 O• Do not make a U-turn unless you can do it safely and without interfering
( J" |$ l  H' T5 s5 E8 gwith other traffic.
0 J: p2 {! T! e! j1 Y  Q* F' b9 T• Outside urban areas U-turns are not permitted on a curve or near the
: k7 g; @8 p5 f, wcrest 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:
$ g3 z% z  a( H  q) f• On a roadway between intersections.
. n: ~! C( i( u• Where a sign prohibits making a U-turn.
• 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。