Maintain a Safe Following Distance (The 3 Second Rule)

Maintain a Safe Following Distance (The 3 Second Rule)

Good Weather - During daylight with good, dry roads and low traffic volume, you can ensure you're a safe distance from the car ahead of you by following the "three-second rule." The distance changes at different speeds.

To determine the right following distance, first select a fixed object on the road ahead such as a sign, tree or overpass. When the vehicle ahead of you passes the object, slowly count "one one thousand, two one thousand, three one thousand." If you reach the object before completing the count, you're following too closely. Making sure there are three seconds between you and the car ahead gives you time and distance to respond to problems in the lane ahead of you.

Inclement Weather, Heavy Traffic, or Night-Time Driving - In heavy traffic, at night, or when weather conditions are not ideal (eg. light rain, light fog, light snow), double the three second rule to six seconds, for added safety.

Poor Weather - If the weather conditions are very poor, eg. heavy rain, heavy fog, or heavy snow, start by tripling the three second rule to nine seconds to determine a safe following distance.

Tailgating - Following a vehicle too closely is called 'tailgating'. Tailgating is an agressive driving behaviour that is easily mistaken for road rage. Use the three-second rule to avoid tailgating. Most rear end collisions are caused by the vehicle in back following too closely. If someone is tailgating you, move to another lane or turn off the road as soon as possible and allow the tailgating vehicle to pass.

Three-Second Rule Safe Interval Should Be > 3 seconds 6 seconds
Speed Distance Traveled For These Conditions > Good Marginal
25 m.p.h. 37 ft. per second 111 ft. 222 ft.
35 m.p.h. 52 ft. per second 166 ft. 312 ft.
45 m.p.h. 66 ft. per second 198 ft. 396 ft.
55 m.p.h. 81 ft. per second 243ft.

486 ft.

65 m.p.h. 96 ft. per second 288 ft. 576 ft.
75 m.p.h. 111 ft. per second 333 ft. 666 ft.
  Safe Following Distance in Feet


Do You Tailgate Dangerously? - Dr Driving (aka Leon James Ph.D.)

Those that drive family & economy cars tailgate less than those who drive sportscars and SUVs by a ratio of 2 to 1.
The results for the 10 states in this sample for which I had enough respondents to make statistical comparisons, show the worst five States with a mean of 21% dangerous tailgating: Colorado (25%), Georgia (20%), Pennsylvania (20%), Michigan (19%), Texas (19%). The lowest tailgating States are: Illinois (8%), New York (10%), Florida (14%), Ohio (15%), California (18%).

There are as you might expect, age differences as well as gender differences. Among young drivers, 19% admit to tailgating dangerously, which is about one in five. This is more than middle aged drivers (15%) and senior drivers (6%). This age pattern recurs in many aggressive driving behaviors: as we get older, we drive less aggressively. Women admit to as much tailgating as men (15%), in general, but once again there are significant influences attributable to the type of car they drive, as show in this table:

Tailgating Type Of Vehicle
Sex Of Driver Family / Economy Cars Sports Cars SUVs
Male 13% 23% 18%
Female 13% 20% 25%

You can see that those drive the "soft" cars (family and economy) tailgate less than those who drive the "hard" cars (sports and SUV) with a ratio of two to one. This holds true for both men and women. However, with SUV drivers we see a reversal between the genders: more female SUV drivers tailgate dangerously, by their own admission, than male drivers of SUVs.

As you browsed 'Maintain a Safe Following Distance (The 3 Second Rule)' you may find interest in following articles . . .


Today's highway drivers simply don't like being behind someone so they drive faster to get around "slower" traffic. No matter how much over the limit you drive, you will have a line behind you bucking to pass.

Typically, you can drive on any Interstate at 10 -15 over the posted limit and still be in the way of a majority of those behind you. Everybody wants to be in a NASCAR race and getting around the fastest driver is the recipe for disaster.

The closer they get, the more I wash my windshield and hose the car behind me. They usually get the message after the second washing.

I have only been driving for 5 weeks and i find the pressure to speed "to keep up with everyone".
I live on a mountain ravine and have not often used the pass to go down the mountain - so i take it slow, its full of dangerous bends, and i value my life, im not trying to hold anyone up, but im not going to put myself at risk so i can get down the mountain 2 minutes faster. When i am confident and have been driving for a while, i will speed up, but i wish people would remember that they were learner drivers once.

Most people think only about themselves and feel a need to challenge themselves to improve their driving skills and perhaps unwittingly at the risk of others. I pull over when a pull off shoulder appears. Sometimes I get a toot of gratitude. Just remember that there are many drivers out there who are good people so don't get discouraged . Keep your tire evened out. 2 psi down on one tire can spoil your confidence. The vehicle should feel as good on left turns as on right turns. No wabbles, confidence will build as you identify the feel for the vehicle.

To the lady that I inadvertently cutoff this evening: I'm sorry. I'm sure that you'll never read this but even as I type it, my conscience is clear. For the record, as I turned right into an empty lane with no oncoming traffic, I couldn't help but notice how you suddenly accelerated through the intersection, a full two cars behind me, trying to close the gap so that nobody could merge in front of you. That coffee can muffler that Daddy must have bought for you was the clue, I could hear it clear as day. As my lane merged with yours, I had both reached the prevailing speed of our shared onramp and signaled my merge. In a word, properly executed. This apparently upset you, though. I guess you were upset that you hadn't accelerated quickly enough to cut me off, but that's neither here-nor-there. As we merged onto the freeway, I moved left one lane. You followed, of course, you were far too close for most people's comfort and your high beams were a bit irritating, but as you no doubt noticed, I never stomped on the brakes to scare you. Instead, I slowed in an attempt to entice you to pass. You however persisted and remained behind me. Really, following me that close when I'm doing 55 MPH should have been an indication that I hadn't acted out of malice. Once we merged to the next freeway, I had a brief opportunity to flash you with my headlights. Again, I'm sorry, but this was my one and only opportunity to voice my disapproval. You now saw fit to take off like a bat out of hell, swerving in and out of traffic. That's fine. But when we share an exit -- because we both live in the same bedroom community -- it doesn't indicate that I'm following you. Instead, it's karma. It's no different than when passing someone and then getting stuck with them at the same red light. Also, I didn't appreciate your call to the highway patrol. I had contemplated making the call before you, however, I again thought better of it and endured your anger. Please. Speak to daddy. Have him buy you either some driving lessons or anger management lessons.

I feel irritated by both aggressive drivers and the too cautious drivers. My basic rule is if you need to press your brake often when it is clearly not a heavy traffic nor there is any road hazard nor steep down hill, then you are not driving properly. Either you are tailgating too closely or you are too cautious. Driving like that waste your gas, wear your car, and make the cars behind you unable to predict the real situation in front. When the cars behind you follow your unnecessary brakes, the traffic jam will be created. If they instead get used to your brakes and ignore, accident can occur if you ever slam your brake to avoid the real danger. So please drive properly so that you can save money, save environment, and save life. Aggressive cars please slow down and create more space in front of you. Cautious drivers, you don't really need to maintain the same buffer distance all the time. The buffer is there for you so that you can sometime get closer the car in front safely.

Secondly, please allow your fellow friends on the road to get into your lane when they politely signal. When people get stuck in the slow lane, nobody wants to go to the slow lane. When everybody maintains a reasonable buffer between cars, it is always possible to let other cars into your lane. If you are cautious drivers at around speed limit, please consider going to the slow lane when possible.

Thirdly, when there are enough traffic on the road, the passing lane is no longer a passing lane. If you don't accept that, aggressive drivers, you will just create traffic jam or accidents the way you drive. Aggressively cutting queues causes other cars to brake and slow down the traffic, and that would in turn annoy more fast drivers behind who would join your bad behaviors. You may be the winner for this round, but you may be the victim of others who drive like you in the traffic ahead. Also, you just need to realize that you would probably save only 5% of your time on the trip if you are lucky. But more likely you will be stuck in the same traffic because of people like you everywhere.

Fourthly, if you just enjoy driving aggressively for fun, go to hell.

Your three second rule seems to defy reality - at this spacing - the Santa Monica Freeway - one of the busiest in the world would have a capacity of about 20 cars per lane mile at 65 mph - so the entire 4 lane freeway (one direction) would have 20 *15 * 4 = 1200 cars on it (from the beach to downtown LA) since the traffic is moving at 65 mph, or 4 + sets of cars/hour - the capacity of the freeway would be 5000 vehicles/hour.

At 30 mph you would have 40*15*2 = the same capacity!!???

I don't doubt that this rule of thumb is safe - but I don't believe it is reality. Can you please show me the traffic counts and speed surveys that support it .

There are signs all up & down the interstates that read "Slower Traffic Keep Right". If someone comes up behind you and you are in the left lane then they are going faster than you are. Obey the law and get to the right. It doesn't matter that the person may be doing 80 or 85 in a 70 mph zone. They may be breaking the law by speeding, but you are breaking it by not moving over. Like someone wrote earlier, it's as simple as just getting over and letting them pass. Look at it this way, if you are traveling 70 and come up on someone who is only going 50 or 55 in a 70 mph zone, you would want them to get over as well.

I have a 20 year old daughter who, I've recently learned, tailgates every time she drives. She drives too fast and when driving at speeds as high as 65 mph, she only leaves 5 to 10 feet between her and the vehicle in front of her. She scares me to death. She is an adult who lives on her own and has bought her own vehicle. No amount of preaching, praying, begging, pleading, or arguing has changed her driving habit. I'm at a loss of how to correct this. I'm afraid she is going to be killed or injured, as well as, kill or injure another motorist. I'm now tempted to contact local police and ask they intervene by pulling her over and siting her.

Many years ago Driver's Education class taught me that if you have a tailgater just add his 3 second following distance to your 3 second following distance. If you have to stop you can do it gently enough so he does not rearend you. Usually the opening in front of you is so tempting he will pass you and the problem is solved. Slowing down below the speed limit about 5 mph also usualy gets rid of them pretty fast. It is all about keeping yourself safe.

Post new comment