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？
谢谢！

EightBelow

U-turns
• Do not make a U-turn unless you can do it safely and without interfering
with other traffic.
- c" p3 b. r# B$ m• Outside urban areas U-turns are not permitted on a curve or near the
! \, R" t& ?0 t/ `; v. Zcrest of a hill where the driver of another vehicle cannot see your vehicle.
7 ^& ^$ p2 y0 C7 V" M( j1 VU-turns are not permitted in urban areas in the following situations:
+ j- O6 h3 G4 T( ~• On a roadway between intersections.
8 K4 K* @8 k; B$ e; A/ O• Where a sign prohibits making a U-turn.
• At an intersection controlled by a traffic-control signal (traffic lights).
- `4 ~4 X+ }+ s• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。