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Orange horizontal rectangular sign with a black border and black text reading SLOW TRAFFIC AHEAD on two lines.
MUTCD
W23-1
Category
work zone
Color
orange
Shape
rectangle horizontal

Slow Traffic Ahead

Traffic ahead is moving much slower than you are, so start easing off now.

W23-1 is posted where work has backed traffic up or where slow-moving work vehicles are operating in the lane. The danger it addresses is the speed difference: rear-end crashes in work zones happen because a driver arrives at a stopped queue at full highway speed. Cover the brake, check your mirror so the vehicle behind you also has time, and expect the queue to appear sooner than you think.

In the same family

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Horizontal orange rectangle with black border reading END ROAD WORK on two lines in black uppercase letters.
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Orange diamond with a thick black arrow curving up and to the right
Curve Right (Work Zone)
Orange diamond with a thick black zig-zag arrow that bends sharply left then right and points up
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