Turn signals, horn and headlights

Key points

1. Always signal when you turn, change lanes, slow down or stop.

   Source: Handbook p. 10

   “Always signal when you turn, change lanes, slow down, or stop.”
   California Driver's Handbook, Handbook p. 10

2. Signal at least 100 feet before you turn and at least five seconds before changing lanes on a freeway.

   Source: Handbook p. 11

   “At least 100 feet before you turn. • Before every lane change. • At least five seconds before you change lanes on a freeway.”
   California Driver's Handbook, Handbook p. 11

3. Use your horn on narrow mountain roads where you cannot see at least 200 feet ahead.

   Source: Handbook p. 11

   “Alert oncoming traffic on narrow mountain roads where you cannot see at least 200 feet ahead.”
   California Driver's Handbook, Handbook p. 11

4. Dim high beams within 500 feet of an oncoming vehicle and within 300 feet of a vehicle you are following.

   Source: Handbook p. 11

   “Dim your high-beam headlights to low beams within 500 feet of a vehicle coming toward you or within 300 feet of a vehicle you are following.”
   California Driver's Handbook, Handbook p. 11

5. Turn on headlights when it is too dark to see 1,000 feet, from 30 minutes after sunset until 30 minutes before sunrise.

   Source: Handbook p. 11

   “When it is too dark to see from 1,000 feet away. • Beginning 30 minutes after sunset. • Until 30 minutes before sunrise.”
   California Driver's Handbook, Handbook p. 11

6. If fog, rain or snow makes you use your wipers, you must turn on your low-beam headlights.

   Source: Handbook p. 11

   “If you need to use your windshield wipers due to fog, rain, or snow, you must turn on your low-beam headlights.”
   California Driver's Handbook, Handbook p. 11

7. It is illegal to drive using only parking lights.

   Source: Handbook p. 11

   “It is illegal to drive using only parking lights.”
   California Driver's Handbook, Handbook p. 11

8. It is illegal to wear a headset or earplugs in both ears while driving.

   Source: Handbook p. 9

   “It is illegal to wear a headset or earplugs in both ears while driving.”
   California Driver's Handbook, Handbook p. 9

9. To warn drivers behind you of a hazard, turn on your flashers or tap your brake pedal three or four times.

   Source: Handbook p. 12

   “Turn on your emergency flashers. • Lightly tap your brake pedal three or four times.”
   California Driver's Handbook, Handbook p. 12

Numbers to know

3 questions from the California practice test

1. 1. How soon must you dim high-beam headlights for an oncoming vehicle?

   1. Only after the other driver flashes lights
   2. Within 100 feet of the oncoming vehicle
   3. Within 500 feet of the oncoming vehicle
   4. Within 300 feet when vehicles approach each other
   Show answer

   Within 500 feet of the oncoming vehicle. For an oncoming vehicle, dim high beams to low beams within 500 feet. The 300-foot number applies when you are following another vehicle, so it is not the oncoming-traffic distance. Waiting for the other driver to flash lights risks blinding them first. The cue is headlights approaching in the opposite lane. Switch down early enough that the other driver can keep their view of the road.

2. 2. When rain or snow makes you use windshield wipers, what else must you do?

   1. Drive with parking lights only
   2. Switch to high beams
   3. Turn on low-beam headlights
   4. Turn off all exterior lights
   Show answer

   Turn on low-beam headlights. California requires low-beam headlights when wipers are needed because of fog, rain, or snow. High beams can reflect glare in bad weather, and parking lights alone are illegal for driving. The cue is simple: if the windshield needs wipers to keep visibility, the car needs low beams so others can see it. Do this even in daytime storms or light snow.

3. 3. You are on a narrow mountain road where you cannot see at least 200 feet ahead. What does the handbook say you may do with your horn?

   1. Sound it to alert oncoming traffic you cannot yet see
   2. Save it strictly for emergencies once a collision is unavoidable
   3. Sound it only after an oncoming vehicle appears
   4. Leave it alone, because horns are prohibited on mountain roads
   Show answer

   Sound it to alert oncoming traffic you cannot yet see. Mountain curves hide oncoming traffic until the last moment, so California lists this as one of the situations where a horn genuinely helps: a short sound warns a driver you cannot see that someone is coming around the bend. Waiting until the other vehicle appears defeats the purpose, since by then you both need braking distance you may not have. Horns are not banned on these roads either. Keep it brief and stay right of the center line, because the horn warns other people but does nothing to widen the lane or slow your own vehicle.

Source: the California Driver's Handbook, Section 5: An Introduction to Driving. This lesson is a plain English summary, not the law itself; where it differs, the manual and the statute govern. Last checked 2026-09-27.