Bad weather, stopping distance and night driving

Key points

1. On dry or wet pavement, keep at least a 3 to 4 second following distance.

   Source: Handbook p. 64

   “A 3- to 4-second following distance is required.”
   What Every Driver Must Know, Handbook p. 64

2. At higher speeds or in bad conditions, increase your following distance to 6 seconds or more.

   Source: Handbook p. 64

   “When speeds are increased, or during adverse driving conditions, increase your following distance up to 6 seconds or more if necessary.”
   What Every Driver Must Know, Handbook p. 64

3. In rain, slow down and allow at least twice the normal following distance.

   Source: Handbook p. 62

   “Slow down and allow at least twice the normal following distance.”
   What Every Driver Must Know, Handbook p. 62

4. Never drive around barricades blocking a flooded road.

   Source: Handbook p. 63

   “If a flooded road is blocked off by safety barricades, do not drive around them.”
   What Every Driver Must Know, Handbook p. 63

5. If fog is so thick you cannot see, pull off, turn on your flashers and wait.

   Source: Handbook p. 63

   “If fog becomes so thick that you cannot see at all, pull off the road. Turn on the four-way emergency flashers and wait for the fog to lift.”
   What Every Driver Must Know, Handbook p. 63

6. Most skids happen when a driver turns too quickly or stops suddenly on slippery pavement.

   Source: Handbook p. 63

   “Most skids happen when a driver tries to turn too quickly or stops suddenly on slippery pavement.”
   What Every Driver Must Know, Handbook p. 63

7. With anti lock brakes, press hard and firmly from the start and hold it until you stop.

   Source: Handbook p. 63

   “With anti-lock brakes, apply the brake with hard, firm pressure from the start and maintain this pressure until you have stopped.”
   What Every Driver Must Know, Handbook p. 63

8. Headlights must be on whenever there is not enough daylight to see people and vehicles clearly at 500 feet.

   Source: Handbook p. 64

   “Headlights must be on any time there is not enough daylight to see people and vehicles clearly at 500 feet.”
   What Every Driver Must Know, Handbook p. 64

9. It is illegal to use or flash high beams within 500 feet of an oncoming vehicle.

   Source: Handbook p. 64

   “It is illegal to use or even flash high-beam headlights within 500 feet of an oncoming vehicle.”
   What Every Driver Must Know, Handbook p. 64

10. Look 20 to 30 seconds down the road to spot hazards early.

    Source: Handbook p. 64

    “Look down the road 20-30 seconds. This rule means always look ahead of the vehicle to spot potential hazards and avoid last-second reactions.”
    What Every Driver Must Know, Handbook p. 64

Numbers to know

3 questions from the Michigan practice test

1. 1. What following interval should a Michigan driver use as a general rule on dry or wet pavement?

   1. Three to four seconds
   2. Exactly ten car lengths
   3. A half second when traffic is light
   4. One second at every speed
   Show answer

   Three to four seconds. Michigan’s general timing method uses a three to four second gap. Pick a fixed roadside point, such as a sign, and count from when the vehicle ahead passes it until your vehicle reaches the same point. The choice of one second is too short for normal driving, while car lengths change with vehicle size and speed, so ten lengths is not a dependable rule. A half second leaves almost no time to react. Increase the interval when speed rises, visibility worsens, or the pavement becomes slippery. The practical cue is to begin counting only after the vehicle ahead passes a stationary object, then lengthen the count when conditions demand it.

2. 2. How should following space change when rain makes the pavement wet?

   1. Increase it because wet pavement requires more stopping time and space
   2. Reduce it because rain cools the brakes
   3. Keep exactly one car length at every speed
   4. Follow more closely so spray cannot enter the gap
   Show answer

   Increase it because wet pavement requires more stopping time and space. Wet pavement needs more stopping time and space, so the driver should increase the following interval. Reducing the gap or following closely makes it harder to react to sudden braking, spray, standing water, or a loss of traction. One car length is not a reliable measurement at every speed because the distance covered changes with speed. Rain may change braking and visibility conditions, but it does not justify keeping the same short space. Slow as needed, look farther ahead, and add room before the vehicle ahead begins braking. Extra space is especially important during the first part of rainfall, when the road can be slick.

3. 3. When must Michigan headlights be on because daylight is insufficient?

   1. Only after midnight
   2. Only when another driver flashes headlights
   3. Whenever there is not enough daylight to see people and vehicles clearly at 500 feet
   4. Only when the vehicle is parked on a shoulder
   Show answer

   Whenever there is not enough daylight to see people and vehicles clearly at 500 feet. Michigan requires headlights whenever available daylight is insufficient to see people and vehicles clearly at 500 feet. The rule is based on visibility, not the clock, so midnight is not the only trigger and a signal from another driver is not required. Parking on a shoulder is unrelated to the visibility requirement. Do not substitute parking lights when headlights are required. As daylight fades or weather limits contrast, turn on the headlights early enough for other road users to see the vehicle and for the driver to see hazards. Use the 500-foot visibility standard as the practical test rather than guessing by time of day.

Source: the What Every Driver Must Know, Chapter 7: Emergencies and Special Situations. 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.