The driver's left arm and hand extended downward is a standard hand signal meaning the driver plans to stop or is slowing down to a stop.

What this hand signal means

  • Left arm straight out of the window, forearm angled down, palm facing backward indicates the driver intends to stop or slow sharply.
  • Drivers behind should reduce speed and be prepared to stop when they see this signal.

Related basic hand signals

  • Left turn: Left arm extended straight out horizontally from the window.
  • Right turn: Left arm out with elbow bent upward at about a right angle.
  • Slow/stop: Left arm out with elbow bent downward, hand pointing toward the road.

Why this signal matters

  • Hand signals are used if brake lights or turn signals fail, or on certain bikes, motorcycles, and older vehicles.
  • Knowing these signals helps prevent rear‑end collisions and improves road safety for drivers, cyclists, and pedestrians.

Information gathered from public forums or data available on the internet and portrayed here.