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
! ~+ x. U5 \; e• Do not make a U-turn unless you can do it safely and without interfering
" r0 A- N, s, @. b  S$ I2 t0 bwith other traffic.
) L1 x) w9 V2 z$ f4 V• 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.
U-turns are not permitted in urban areas in the following situations:
/ R' B' t7 Q) J( q6 r- V- M• On a roadway between intersections.
• Where a sign prohibits making a U-turn.
8 P8 ?, q1 l& Q# @• At an intersection controlled by a traffic-control signal (traffic lights).
2 X7 X6 a: l5 X% {• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。