Should You Be Following the 3-Second Rule While Driving?

by Staff | June 27th, 2024

Driving a car presents many possible risks; 42,154 people were killed in motor vehicle accidents in the US in 2022. Most of these accidents were caused by driver error.

This means that by following a few rules while driving, you can decrease your risk of harming yourself and others. One rule that’s simple to follow and helps reduce your chances of rear-ending someone else’s vehicle is the 3-second rule.


Many crashes are caused by drivers following the vehicle in front of them too closely. Without sufficient space between vehicles, drivers cannot stop in time if the car in front brakes suddenly.

The 3-second rule advises you to keep a distance of three car lengths between you and the car in front. This has also been described as the distance you could travel in three seconds at an average speed. Maintaining this space between cars is a simple and proven way to avoid rear-end collisions.


The National Safety Council’s Two-Second Plus Rule for safe following distance, introduced in the 1960s, proved inadequate by the 1990s due to vehicle size variations and actual stopping distances. With modern driving distractions like cell phones and music playlists increasing drivers’ reaction times, the recommended following distance has been extended to three seconds, providing a safer buffer for today’s driving conditions.

The three-second rule is based on perception distance, reaction distance, and braking distance. It extends the original 2.5-second guideline used by highway designers to account for increased driver distractions. This rule allocates 1.75 seconds for perception of a hazard, 0.75 seconds for reaction, and adds a 0.5-second safety buffer, providing more time to avoid collisions when vehicles ahead stop suddenly.


Calculating the distance you need between the car in front and your vehicle is relatively easy. Pick a stationary object by the road, such as a tree or traffic sign; once the car in front of you reaches that object, begin counting and note how long it takes you to pass the same object. If you reach the object before you have slowly counted to three, you are too close to the vehicle ahead of you, and likely won’t have enough time to safely emergency brake if needed and avoid a rear-end collision.

This method will give you an idea of a safe following distance and leaves plenty of time to stop if the car in front suddenly brakes.

Driving too close to another vehicle is dangerous and causes many avoidable accidents. It is known as tailgating and is considered an aggressive type of driving that puts both vehicles’ occupants at much greater risk of a rear-end crash.


The 3-second rule adequately deals with daylight and good weather conditions. However, at night or when the weather conditions deteriorate, greater distances between vehicles will be necessary.

Inclement weather like rain or snow leads to worse visibility and slippery road conditions. These factors increase the risk of accidents, making it prudent to double the 3-second rule to a 6-second following distance.

Fog makes driving conditions hazardous because it is challenging to see what is in front of you. When you encounter heavy fog, it is appropriate to triple the time between you and the vehicle ahead to 9 seconds. This allows plenty of room for stopping despite the lack of visibility.


Weather and road conditions aren’t the only reason why you might consider doubling your following distance. The California Driver Handbook advises drivers to increase their following distances and give more space to drivers who present greater potential danger. These drivers and people include:

  • Drivers whose view of you is obstructed
  • Drivers who may be forced into your lane to avoid an obstruction, such as a pedestrian or bicyclist on the shoulder
  • Drivers who are backing out into your lane
  • Distracted people like delivery drivers, construction workers, or drivers talking on their phones
  • Drivers who slow down for no apparent reason (for example, they may be distracted by searching for a house number)


When conditions are bad, or visibility is poor, you should drive slowly and use low beams or fog lights. You need to ensure other drivers can see you and you have plenty of room to stop.

If the visibility gets too bad, you should stop in a well-lit area and wait for conditions to improve.

If you are towing a trailer or driving an RV, your required stopping distance may be greater due to the vehicle’s weight. Adjust the space between you and the vehicle ahead accordingly.


The 3-second rule does not apply where the car in front is stationary due to being stopped at a stop sign or traffic light. There is no reason to leave large spaces between vehicles in these situations.

In stop-and-go traffic in town, it is difficult to judge a 3-second space. However, it is always wise to leave a big enough gap between the vehicles so that you can stop if the car in front brakes suddenly.


If you have been rear-ended by a driver not following the 3-second rule or tailgating, speak to the auto accident attorneys at Berg Injury Lawyers today. Our California car accident lawyers offer a free case consultation and can help you get the compensation you deserve.

We believe everyone deserves effective legal representation when injured in an accident caused by another party’s negligence. That is why we offer a No Fee Guarantee, meaning we only get paid if you recover damages. Start your case now by contacting our team of injury lawyers today.

Originally published December 13, 2021.