这篇解释的很清楚，我个人认为。（ZT）

[both drivers have green arrows pointing in their intended direction
- one is turning right on a right arrow, the other making a U-turn on
a left arrow with no sign prohibiting that practice. They collide.
Whose fault?]

First of all, your premise that the traffic engineers would permit
both a right-arrow (for, say, northbound turning to eastbound) and a
left-arrow (for westbound turning to southbound) to be lit at the same
intersection at the same time _without_a_sign_prohibiting_U-turns_
would be very bad planning. If they are going to permit U-turns
there, they should have the Left-or-U-turn arrow light illuminated at
a DIFFERENT point in the signal sequence than when they have the
_right_ turn arrow illuminated, _because_ of the danger of such
traffic conflict.

But I'm not denying that it may occur in some places, either due to
bad planning or unintentionally if the "No U-turn" sign is missing,
perhaps blown down by a recent storm.

Since the _signals_ for both drivers are "green," that means they are
each entitled to proceed through the intersection _after_ yielding the
right of way to any other traffic in the intersection which has a
superior right of way. A green light or green arrow does NOT mean
"damn the torpedoes, full speed ahead."

Thus, the default rule of right-of-way for conflicting traffic applies
- the one approaching the point of potential collision from the
other's left must yield the right-of-way to the one approaching that
point from his _right_. Here, the guy making the U-turn would be
approaching the right-turning driver from the right-turning driver's
LEFT side, and the U-turning guy would consequently see the right-
turner approaching him from the U-turner's RIGHT side. Thus the U-
turner would have to yield to the right-turner.
--
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Mike Jacobs
LAW OFFICE OF W. MICHAEL JACOBS
10440 Little Patuxent Pkwy #300
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