Following distance, weather and staying alert

Key points

1. A rule of thumb is 1 car length, about 20 feet, of following distance for every 10 mph of speed.

   Source: Handbook p. 94

   “the rule of thumb most often used is to keep one car length back (about 20 feet) for each 10 miles per hour of speed.”
   New Jersey Driver Manual, Handbook p. 94

2. Three seconds plus rule: pick a fixed object, and if it takes at least 3 seconds to reach it after the car ahead passes it, you have room for a sudden stop.

   Source: Handbook p. 95

   “If it takes at least three seconds before your vehicle passes the object, a motorist should have enough distance for a sudden stop.”
   New Jersey Driver Manual, Handbook p. 95

3. On wet roads, stretch the three seconds plus rule to 4 or more seconds.

   Source: Handbook p. 97

   “The three-seconds-plus rule should be increased to four or more seconds.”
   New Jersey Driver Manual, Handbook p. 97

4. On snow covered roads, keep a following distance of 6 seconds or more.

   Source: Handbook p. 99

   “A good rule on snow-covered roads is to maintain a following distance of six seconds or more.”
   New Jersey Driver Manual, Handbook p. 99

5. Tires can start to hydroplane at about 35 mph, and after 55 mph they may leave the road surface completely.

   Source: Handbook p. 97

   “starting at about 35 mph, which could cause a motorist to lose control of his/her vehicle. Chances of hydroplaning increase as speeds increase. After 55 mph, tires may totally leave the road surface.”
   New Jersey Driver Manual, Handbook p. 97

6. To avoid hydroplaning, do not drive on bald tires and slow down in heavy rain, standing water or slush.

   Source: Handbook p. 97

   “To avoid hydroplaning, do not drive on bald or badly worn tires, and slow down when heavy rain, standing water, or slush is present.”
   New Jersey Driver Manual, Handbook p. 97

7. In a skid, turn in the direction the rear of the car is skidding, without oversteering.

   Source: Handbook p. 104

   “To avoid a spin, the motorist should turn in the direction the rear of the vehicle is skidding, without over steering.”
   New Jersey Driver Manual, Handbook p. 104

8. Look at least 12 seconds ahead as you drive.

   Source: Handbook p. 101

   “A motorist should look at least 12 seconds ahead.”
   New Jersey Driver Manual, Handbook p. 101

9. On long drives, avoid highway hypnosis and rest every 2 hours or share the driving.

   Source: Handbook p. 93

   “It is also recommended that a motorist rest every two hours and/or share the driving with another licensed motorist.”
   New Jersey Driver Manual, Handbook p. 93

10. If you are angry or excited, take time to cool off before you drive on.

    Source: Handbook p. 90

    “If a motorist is angry or excited, he/she should take time to cool off.”
    New Jersey Driver Manual, Handbook p. 90

Numbers to know

3 questions from the New Jersey practice test

1. 1. What following distance rule of thumb does the manual describe?

   1. About one car length, or 20 feet, for each 10 miles per hour
   2. One car length for every 25 miles per hour
   3. Ten feet for every 20 miles per hour
   4. A fixed five-second distance in all conditions
   Show answer

   About one car length, or 20 feet, for each 10 miles per hour. The manual's rule of thumb is about one car length, or 20 feet, for each 10 miles per hour of speed. It also says there is no perfect following-distance rule and that space should increase at high speeds or in bad weather. The choices using 25 mph, 10 feet, or one fixed five-second distance change the stated figures or ignore conditions. Use the guideline as a starting point, then add room when rain, snow, fog, traffic, or stopping conditions reduce the time available to react.

2. 2. Why does the three-seconds-plus rule help a driver following another vehicle?

   1. It guarantees exactly three seconds of braking
   2. It replaces watching traffic ahead
   3. It permits a shorter gap on wet roads
   4. It helps judge enough space for a sudden stop
   Show answer

   It helps judge enough space for a sudden stop. The method uses a fixed object to estimate whether the following gap can accommodate an unexpected stop. It is not a promise of a three-second braking time and never replaces scanning the road. Wet conditions require four or more seconds, not less. Choose a tree or sign, begin counting after the vehicle ahead passes it, and seek at least three seconds in favorable conditions.

3. 3. When should a New Jersey driver slow down to help avoid hydroplaning?

   1. Only after the tires leave the road surface
   2. Only when driving on a dry center lane
   3. When heavy rain, standing water, or slush is present
   4. After accelerating above 55 mph
   Show answer

   When heavy rain, standing water, or slush is present. The manual specifically advises slowing down when heavy rain, standing water, or slush is present because those conditions increase the chance of hydroplaning. Waiting until the tires leave the surface is dangerously late, and accelerating increases the loss of control risk. A dry center lane can be useful during a heavy rainstorm on a multilane highway, but it does not remove the need to reduce speed. The practical cue is water on or across the roadway, especially when visibility and traction are deteriorating.

Source: the New Jersey Driver Manual, Chapter 5: Defensive 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.