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？
谢谢！

EightBelow

U-turns
  r. k% P( y, U3 J4 d• Do not make a U-turn unless you can do it safely and without interfering
with other traffic.
% p: Q8 ~4 p  o) P3 P: I0 o• Outside urban areas U-turns are not permitted on a curve or near the
3 h7 @! f; q0 B7 y* U' ecrest 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.
• Where a sign prohibits making a U-turn.
% ]7 u5 {& X8 I7 F; F6 M$ x• At an intersection controlled by a traffic-control signal (traffic lights).
" w' @% i! ]( ?/ S; c! }3 V• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。