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
' P: @7 {2 L1 ?+ P- g" a• Do not make a U-turn unless you can do it safely and without interfering
# f/ D8 p5 n7 ]0 Y0 c# _% Hwith other traffic.
• Outside urban areas U-turns are not permitted on a curve or near the
3 _) M" z5 j/ V; J* Ccrest of a hill where the driver of another vehicle cannot see your vehicle.
% z  Y+ Y  F0 ^: w7 ]7 _U-turns are not permitted in urban areas in the following situations:
• On a roadway between intersections.
6 M# [4 X4 p4 b2 t• Where a sign prohibits making a U-turn.
- U6 t) ?0 {% {9 C5 @2 q+ b" s• At an intersection controlled by a traffic-control signal (traffic lights).
4 G: |" j8 O. [8 X• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。