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？
! ^7 x. y9 U. a3 q谢谢！

EightBelow

U-turns
• Do not make a U-turn unless you can do it safely and without interfering
with other traffic.
; E$ t; u& Z+ `1 ]9 ^• Outside urban areas U-turns are not permitted on a curve or near the
/ u9 ^( H4 h! T" vcrest of a hill where the driver of another vehicle cannot see your vehicle.
/ L$ q) N' o9 A; |9 \* yU-turns are not permitted in urban areas in the following situations:
. s. [1 F  P" G• On a roadway between intersections.
• Where a sign prohibits making a U-turn.
" J6 \8 h4 P9 C7 v: n* R! S4 {/ J• 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。