A yellow diamond-shaped sign with a black arrow is a warning sign that usually indicates a change in the direction of the road ahead – most commonly, a curve or a sharp turn is coming up.
The exact shape of the arrow gives more detail:
If the arrow is a curved arrow, it means the road will curve in that direction (left or right). For example, a sign with a black arrow that curves to the right warns you of a right curve ahead.
If the arrow has a sharp ninety-degree turn (like a right angle), it indicates a sharp turn (not just a gentle curve) in that direction.
Sometimes the arrow is a squiggly line, indicating a series of curves (like an S-curve or winding road ahead).
If the arrow splits (like a main arrow with a branch), it could indicate merging traffic or that you need to stay one side of an obstruction, but those usually have other symbols too. The most straightforward “arrow on yellow diamond” is about road direction.
So, assuming it’s the common scenario: a yellow diamond with one black arrow:
For example, a right-turn arrow (90-degree angle arrow pointing right) means the road ahead makes a sharp right turn – you should slow down and be prepared to turn right with the road.
A curved arrow pointing left means a gentler curve to the left is upcoming – again slow to a safe speed to navigate the curve.
Often, these signs are paired with an advisory speed plaque (an additional smaller sign) beneath them. For instance, below the arrow sign it might say “25 mph”, suggesting that you should take that curve at 25 mph or less for safety.
These warning arrow signs are placed in advance of the curve/turn to give you time to slow down.
In summary, a yellow diamond with a black arrow is telling you the road will change direction in the way the arrow depicts, so prepare to follow the arrow (turn/curve) and adjust your speed accordingly. It’s there to prevent you from being surprised by a bend in the road.
