5.2 Horn, Headlights, ADAS, Night Driving & Drowsy Driving

Communicating with other road users, and seeing them, are core defensive skills. The Manual's rules on horns, headlights and night driving are short, but they are packed with numbers.

Using Your Horn

Elsewhere the Manual adds two situations where the horn is wrong: never honk at a blind pedestrian (section 6.1), and don't honk near animals (section 12.3).

Headlight Rules

You must use headlights and taillights:

• from one-half hour after sunset until one-half hour before sunrise;
• when you cannot clearly see people or vehicles 500 feet ahead because of poor light or weather;
• whenever you use your windshield wipers. Daytime running lights are not sufficient;
• in rain, snow, fog or other weather that makes it hard to see;
• any time you have trouble seeing other vehicles;
• to alert another driver to turn on their headlights;
• while driving through a tunnel.

Emergency flashers and breakdowns

Use emergency lights and signals when your vehicle breaks down so others can see it. Move it as far to the side as possible and stay off the road. Never change a flat tire in a traffic lane; wait for help. You may also use the flashers to warn drivers behind you about a crash or hazard ahead.

Advanced Driver Assistance Systems (ADAS)

Many vehicles now include ADAS, such as automatic emergency braking, lane departure warning and blind-spot warning. They make driving safer only if used correctly. Read the owner's manual to learn your vehicle's systems, and remember that the driver is still the most important safety feature. The same idea shows up on the road test: specialized features need not be disabled, but the examiner tests your skills without relying only on them (section 3.2).

Night Driving

Night driving is more dangerous than daytime driving because vehicles, pedestrians and obstacles are harder to see.

• Don't drive when tired or drowsy.
• Drive more slowly, especially in unfamiliar areas. Keep a speed that lets you stop within the distance you can see ahead.
• Leave more space, especially near trucks and heavy equipment.
• Set the inside mirror to "night" to cut glare from behind, and keep interior lights off.
• Don't look straight at oncoming headlights. Look toward the lower right side of your lane.
• Keep windows and headlights clean.
• If another driver flashes headlights at you, your lights may be off or your high beams on.

High beams

• Use high beams only in dark areas where you can't see the road surface ahead.
• Dim to low beams within 500 feet of an oncoming vehicle and within 200 feet of a vehicle you are following.
• If an oncoming driver keeps high beams on, you may flick your headlights once as a reminder. If they still don't dim, stay to the right and do not turn on your own high beams.
• Dim for an oncoming bicyclist too (section 6.1). When passing a stopped emergency vehicle at night, dim your high beams (section 14.1).

Drowsy Driving

Drowsy driving can be deadly: the Manual reports 633 deaths in 2020 from drowsy-driving crashes (NHTSA). These crashes most often:

• happen between midnight and 6 a.m., or in the late afternoon;
• involve a single driver with no passengers running off the road at high speed;
• happen on rural roads and highways.

The only true protection is enough sleep and not driving when tired. Coffee and a nap in a safe place help only briefly. If you must drive between midnight and 6 a.m., watch for warning signs such as drifting across lines or hitting rumble strips. Alcohol increases drowsiness, and many prescription and over-the-counter medicines list drowsiness as a side effect.

On long highway trips the Manual also advises stopping to stretch every two hours or 100 miles and leaving the highway if "highway hypnosis" sets in (section 11.1).

Planning the Night Lesson

• Schedule at least one dusk or night lesson so students practice dimming, glare control and speed-to-sight-distance judgment with an instructor.
• Practice the 500/200 rule out loud. Have the student call "oncoming, dim" and "closing on the car ahead, dim" before acting.
• Link drowsiness to the JOL night restriction. The 12:30–5:00 a.m. window overlaps the Manual's peak drowsy-crash hours.