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？
" Y' F! a; d, B/ A) f谢谢！

EightBelow

U-turns
7 z! a& X8 a; V1 U+ H7 P• Do not make a U-turn unless you can do it safely and without interfering
5 u" P& e$ U; ^  s+ `with other traffic.
• Outside urban areas U-turns are not permitted on a curve or near the
& x& f# u$ {5 A) j. ccrest of a hill where the driver of another vehicle cannot see your vehicle.
; z7 [8 O8 t( {5 b! [U-turns are not permitted in urban areas in the following situations:
2 T1 n6 X2 I% O# g7 X" F• On a roadway between intersections.
• Where a sign prohibits making a U-turn.
0 j8 W6 X' ^) J8 P• At an intersection controlled by a traffic-control signal (traffic lights).
5 Q: `  S! r8 b# y8 C* m% q• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。