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？
4 }9 I* c" L; `谢谢！

EightBelow

U-turns
5 L9 S+ G9 i+ O% M5 Q• Do not make a U-turn unless you can do it safely and without interfering
with other traffic.
' }8 c" _7 }+ t, [- F• 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:
0 d1 q' u9 {- t• On a roadway between intersections.
% r! L( [: ]! @% ?• Where a sign prohibits making a U-turn.
5 Q5 s. A! W9 q• At an intersection controlled by a traffic-control signal (traffic lights).
" P% [# D! M8 P( j) {: A0 |• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。