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？
. V( S* l, D3 I谢谢！

EightBelow

U-turns
• Do not make a U-turn unless you can do it safely and without interfering
with other traffic.
• 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.
7 C) P, x6 J* D3 u8 MU-turns are not permitted in urban areas in the following situations:
: t- }' c- V' W' ]5 X$ _5 J' S• On a roadway between intersections.
• Where a sign prohibits making a U-turn.
0 @( ?0 S* M+ Z! I, a% }$ X  g• 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。