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。
7 n9 T# ^* w2 {" ?) F+ z9 P0 N  ?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
" ?' q9 ~7 ~1 ?% |4 Mwith other traffic.
• 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:
8 P4 d1 U  e) t1 n• On a roadway between intersections.
# V. {5 }$ `- S. {. ~2 B• Where a sign prohibits making a U-turn.
• At an intersection controlled by a traffic-control signal (traffic lights).
' v* u( y& t% u4 |9 \& p8 e! Y' @• At an alley intersection.

无语

有红绿灯的地方U-Turn是违规的。