This sign is on the left side of a two-lane road. What does it tell you?

Correct answer: A no-passing zone begins here; do not pass on the left from this point

Why

No-passing zones are placed where passing is especially dangerous, for example near hills, curves and intersections. In the zone, the pavement usually has a solid yellow line on your side of the center line. The law makes three exceptions: you may go left of that line to turn left into or out of an alley, private road or driveway, to go around an obstruction in your lane, or to pass a bicycle or moped that moves slower than traffic when you can do it safely. In each case, yield to oncoming traffic that is close enough to be a hazard.

Verified against Utah Driver Handbook · Warning signs · p. 58