Key points
Look 20 to 30 seconds ahead so you have time to prepare for traffic conditions.
Source: Handbook p. 61
“Looking 20 to 30 seconds ahead will allow time to prepare for traffic conditions.”
Louisiana Class D and E Driver's Guide, Handbook p. 61At 60 mph, if you cannot see at least 400 feet ahead, you are driving too fast for your visibility.
Source: Handbook p. 62
“At 60 mph, if you cannot see at least 400 feet ahead, you are driving too fast for your visibility. At 30 mph, if you cannot see at least 150 feet ahead”
Louisiana Class D and E Driver's Guide, Handbook p. 62If stopped at an intersection, look left, right and left again before entering.
Source: Handbook p. 62
“If stopped, look left, right and left again before entering the intersection.”
Louisiana Class D and E Driver's Guide, Handbook p. 62Before changing lanes, identify a 4 to 5 second gap, signal and look again.
Source: Handbook p. 63
“Identify a 4 to 5 second gap in traffic, signal and look again in the direction of the lane change.”
Louisiana Class D and E Driver's Guide, Handbook p. 63At 50 mph on dry pavement with good brakes, braking alone can take about 158 feet.
Source: Handbook p. 64
“At 50 mph on dry pavement with good brakes, it can take about 158 feet.”
Louisiana Class D and E Driver's Guide, Handbook p. 64From the moment you see a hazard until you stop, at 50 mph you travel at least 268 feet.
Source: Handbook p. 65
“until you can bring your vehicle to a complete stop. At 50 mph, your vehicle will travel a minimum of 268 feet.”
Louisiana Class D and E Driver's Guide, Handbook p. 65Doubling speed from 20 to 40 mph makes the impact and braking distance 4 times greater.
Source: Handbook p. 65
“When you double your speed from 20 to 40 mph the impact is 4 times greater. The braking distance is also 4 times longer.”
Louisiana Class D and E Driver's Guide, Handbook p. 65Use the 3 second rule. If you pass the checkpoint in less than three seconds, you are too close.
Source: Handbook p. 65
“If it takes less than three (3) seconds for your car to pass the checkpoint, you are following too closely.”
Louisiana Class D and E Driver's Guide, Handbook p. 65Increase to four seconds in bad weather or on wet pavement.
Source: Handbook p. 66
“Increase the following rule (above) to four (4) seconds during bad weather or when driving on wet pavement.”
Louisiana Class D and E Driver's Guide, Handbook p. 66
Numbers to know
| Number | What it means | Manual |
|---|---|---|
| 20 to 30 seconds | how far ahead to look | Handbook p. 61 |
| 60 mph: 400 feet; 30 mph: 150 feet | minimum visibility needed at these speeds | Handbook p. 62 |
| 4 to 5 seconds | gap to find before changing lanes | Handbook p. 63 |
| 50 mph: 158 feet braking | braking distance on dry pavement | Handbook p. 64 |
| 50 mph: 268 feet total | minimum total stopping distance | Handbook p. 65 |
| 20 to 40 mph: 4 times | impact and braking distance when speed doubles | Handbook p. 65 |
| 4 seconds | following distance in bad weather or on wet pavement | Handbook p. 66 |
| 3 seconds | minimum following distance | Handbook p. 65 |
3 questions from the Louisiana practice test
1. How far ahead must a Louisiana driver be able to see at 60 mph to be driving safely for visibility?
- At least 400 feet, and 150 feet at 30 mph
- At least 100 feet
- At least one mile
- At least 50 feet
Show answer
At least 400 feet, and 150 feet at 30 mph. At 60 mph, if you cannot see at least 400 feet ahead you are driving too fast for your visibility, and at 30 mph you need to see at least 150 feet. At 30 mph it takes about 2 to 3 seconds or 123 feet to react and stop, and total stopping distance at 50 mph is a minimum of 268 feet. Slow down whenever fog, rain or darkness shortens your view.
2. What total stopping distance does the Louisiana guide give at 50 mph?
- About 100 feet
- A minimum of 268 feet, including perception, reaction and braking
- About 50 feet
- About 1,000 feet
Show answer
A minimum of 268 feet, including perception, reaction and braking. Total stopping distance is the minimum distance traveled in ideal conditions including perception distance, reaction distance and braking distance, and at 50 mph your vehicle will travel a minimum of 268 feet before it stops; braking alone takes about 158 feet on dry pavement with good brakes. It takes much longer and farther to stop than most drivers realize, which is why following distance matters.
3. When should a driver increase the normal three second following gap to four seconds?
- Only when traveling below 15 mph
- During bad weather or when driving on wet pavement
- Whenever the road is dry and empty
- Only after the vehicle ahead changes lanes
Show answer
During bad weather or when driving on wet pavement. Wet pavement and bad weather increase the distance needed to stop, so the manual directs drivers to expand the ordinary three second rule to four seconds. The added time creates room for reduced traction, limited visibility, and a slower response from the vehicle ahead. It is not reserved for low speed travel, and dry pavement does not create the same specific need. Begin with a fixed roadside object, count after the lead vehicle passes, and drop farther back whenever conditions make stopping harder.
Practice this topic
Lock it in with safe driving questions from the free Louisiana practice test. Every answer comes with a plain English explanation.
Source: the Louisiana Class D and E Driver's Guide, Chapter 5: Safe Driving Habits. 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.