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？
: L: y9 H) H. P8 M4 V) ~6 f' o谢谢！

EightBelow

U-turns
• Do not make a U-turn unless you can do it safely and without interfering
- P, U8 R# a2 s$ ~$ T( s) }with other traffic.
- s# b4 v# S, L8 M9 S7 j• 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.
$ O/ l* E0 w- xU-turns are not permitted in urban areas in the following situations:
# W+ z5 L5 n5 e. S0 q3 l4 A- L• On a roadway between intersections.
• Where a sign prohibits making a U-turn.
$ E9 i7 R$ K: j3 L5 t• 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。