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。
6 o, d3 z1 k. j7 y7 {请问u-turn到底是不是合法的？
谢谢！

EightBelow

U-turns
, K0 f4 e" B4 Y( N; w• Do not make a U-turn unless you can do it safely and without interfering
with other traffic.
  s1 B0 o, F; |4 a( L( o. a• 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:
- L7 M$ |, |( X. Y, Y+ [. J6 H" ?• On a roadway between intersections.
9 i7 e( W2 W' `+ |9 r  A# 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。