Roadwise States Louisiana Driving lessons Following distance: the 3- and 4-second rules Louisiana driving lesson · Space, Speed & Stopping
Following distance: the 3- and 4-second rules A 3-minute lesson from the Louisiana course. Read the rules and examples, follow the handbook page references, and check your understanding before you move on.
Read time 3 minutes
Course unit Space, Speed & Stopping
Checkpoint questions 6
Source pages 70, 71 Most people can't judge distance in feet, so count seconds instead. The 3-second rule works at any speed in good conditions, and many situations call for four seconds or more.
Using the 3-second rule: Choose an object ahead of the car in front of you: a sign, pole or tree When that car passes it, count 'one-one-thousand, two-one-thousand, three-one-thousand' If you reach the object before you finish, you're following too closely Drop back and recount until you're no closer than three seconds Handbook p. 70 ↗ Know the rule
If another vehicle moves into the space ahead of you, drop back to a safe following distance again.
Handbook p. 71 ↗ Know the rule
Increase to four seconds in bad weather or on wet pavement.
Handbook p. 71 ↗ Use a 4-second (or longer) following distance when: Roads are slippery The driver behind you wants to pass: slow down so the pass finishes sooner Following a motorcycle, which may fall on wet or icy roads, gravel or metal surfaces Following trucks, buses, vans or vehicles towing campers that can't see you Pulling a trailer Visibility is low from darkness or bad weather Following police cars, ambulances or fire trucks Behind vehicles that must stop at railroad crossings Stopped on a hill, where the car ahead may roll back Handbook p. 71 ↗ Vehicles that stop at railroad crossings: Transit buses School buses Vehicles carrying hazardous materials Handbook p. 71 ↗ Know the rule
If you're being followed closely, pull to the right and let the vehicle pass.
Handbook p. 71 ↗ Know the rule
Large vehicles block your view of the road ahead; falling back gives you more room to see.
Handbook p. 71 ↗ Put it into practice
It starts raining on your commute. You were three seconds behind the car ahead; drop back to at least four seconds, and more if the road turns slick.
A useful reminder 3 seconds normally; 4 seconds in bad weather, behind motorcycles, and behind vehicles that can't see you.
Check your understanding Read the question, decide on an answer, then open it to check the explanation. These are Roadwise study questions based on the source handbook.
Under the 3-second rule, what does it mean if your car passes a fixed checkpoint less than 3 seconds after the vehicle ahead? You are following too closely You have the ideal following distance You are following too far back You are safe, but only on dry roads Answer: You are following too closely
Reaching the checkpoint in under 3 seconds means you need to drop back to a safer following distance.
Handbook p. 70 ↗ When should you increase your following distance to a 4-second rule instead of 3? Only on a straight, flat highway During bad weather or on wet pavement Only on interstate highways When traffic is light Answer: During bad weather or on wet pavement
Wet or poor-weather conditions call for the longer 4-second following distance.
Handbook p. 71 ↗ Why should you increase your following distance when behind a motorcycle? Motorcycles always stop faster than cars Motorcycle brake lights are hard to see Riders can fall, and you need room to avoid them Motorcycles have longer stopping distances than cars Answer: Riders can fall, and you need room to avoid them
A fallen motorcyclist needs extra space to avoid a collision, so a 4-second gap is recommended.
Handbook p. 71 ↗ Why should you leave extra following distance behind large trucks and buses? They stop faster than cars can They accelerate faster than cars They must drive below the limit They can't see you and they block your view Answer: They can't see you and they block your view
Extra distance behind large vehicles improves visibility and gives the driver a chance to see you.
Handbook p. 71 ↗ How do you measure the 3-second following rule? Estimate the number of car lengths between vehicles Count seconds past a fixed object Use your speedometer reading alone Watch the vehicle's brake lights only Answer: Count seconds past a fixed object
The 3-second rule uses a time count from a fixed roadside object, since drivers judge distance poorly.
Handbook p. 70 ↗ You are approaching a railroad crossing behind another vehicle. What following distance guidance applies? Keep your normal 3-second gap Close up so you clear the tracks together Leave extra room only behind trucks Leave extra room; some vehicles must stop there Answer: Leave extra room; some vehicles must stop there
Some vehicles (school buses, hazmat carriers) must stop at railroad crossings, so extra following distance is recommended.
Handbook p. 71 ↗ Previous lesson Stopping distance & speed Next lesson Speed limits & the general speed law More in Space, Speed & Stopping About the source Roadwise’s Louisiana course uses the driver handbook edition supplied with this study pack. This lesson cites source pages 70, 71. The linked PDF is a third-party mirror of the handbook, rather than a government-hosted page.
Open the handbook source PDF · View the source edition
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