The 2-second following distance rule...WHY does it work?

Question

-How can experts be sure this is true and works?

-isn't 2 seconds a measure of time, instead of distance?

-would 2 seconds be safe on the interstate highway?

THANKS!

Answer 1

You need some numbers. At 60 mph your car is travelling at 88 ft per second and 2 seconds will give you 176 ft of stopping space. Most cars can stop from 60 mph in close to or less than that. It works for 30mph too 44 ft per second equals 88 ft . The only problem with that is reaction time taken to recognize the need for stopping.

Answer 2

Actually, 2 seconds doesn't work, 3 is safer.  The theory is that, the faster you go, the greater distance is left if you have a 2-second gap between vehicles.  The problem is, if you have a 2.5 second reaction time from the following driver, and the car in front has better tires, there will be a collision.   3 seconds is safer, and gives a much better chance of avoiding accident and injury.  People that leave 2 seconds operate on the theory of "I haven't had an accident yet, so it must be safe".  In practice, 2 seconds is only adequate if all drivers have good reaction time, good tires, good brakes, and nobody talks on the cell phone, or changes radio stations, or even blinks.  It also assumes the weather and road conditions are perfect.  Chain reaction accidents, while rare, are painful evidence that the 2-second rule doesn't work.

Answer 3

Its more of a measure of distance. Time just makes it easier than saying 5 car lengths. It works because of the time it takes you to react to a situation

Answer 4

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Do not take any notice of UCANTCME, his advice on this question is DANGEROUS!!

He/She is quoting under a second gap.

For every 10mph = 14.66 f/sec approx. Therefore, 2 seconds at 50mph = 147 feet approx.

So, UCANTCME's 5 car lengths (average car length 13 feet) = 65feet

2 second rule = 147 feet @ 50mph

UCANTCME = 65 feet @ 50mph??? Sounds bloody dangerous to me.

To your question = Yes, it should, if you are alert, your driving skills are honed, you are on a decent road surface and the weather and condition and type of your vehicle is good. Increase your distance if any of the above criteria are in doubt.

This link is very informative.

http://www.csgnetwork.com/stopdistinfo.h...

Good to see someone trying to be a proficient driver.

Answer 5

Use this instead, it will work better.

If you are driving less than 20 mph it will work but the faster you are driving it will not work, try using the 10 mph rule because it is better.

Example: if you are driving at 50 mph, then stay back 5 car lengths, one car length for ever 10 mph.

Answer 6

Velocity (feet/second) * time equals distance.

Giving you a set distance won't work since you need more distance at higher speeds.  The time works out well since the distance you're allowing will change based on the speed you're travelling.

It works based on the assumption that the car ahead of you can't stop much faster than you can.  You're going to have at least 0.2 seconds reaction time before you even start to put on the brakes.  Unless you're driving a semi and the person in front of you is driving a yugo, it shouldn't take 1.8 more seconds for you to come to a stop than the person in front of you.

The exception?  The person in front you comes to an abrupt stop because they hit a stopped car in front of them.  The 2 second rule might not help you in this case.  This is how those chain reaction accidents happen on the highway.  One driver wasn't paying attention or was following too close and now the timing for everyone behind him is fouled up as well.

Fred C:  If a person's reaction time is greater than 2 seconds, then they must be drunk - or else not paying attention, which certainly is a realistic assessment nowadays.  Still, talking on your cell phone, reading a map, doing your make-up, trying to find the lit ash that fell off of your cigarette, turning around and yelling at the kids in the backseat, looking for a new CD .... all while driving ..... are dangerous behaviors in themselves.  If a driver is paying attention, their reaction time should be less than half a second.

Try this reaction test:  http://getyourwebsitehere.com/jswb/rttes...

Try it while trying to get the best possible reaction time.  Try it while dialing your cell phone.  Try it while locating and putting a CD in your computer.  Etc.

Answer 7

It's a rough guideline. The faster you go, the more ground you cover in 2 seconds. So when you are going 60mph you end up much farther behind the car then you do when going 30mph.

Answer 8

Basically, you should always manage your time and distance when you are in any traffic situation in a vehicle.

Without going into details about mathematical calculations, simply allow yourself time and distance to -

Scan around your vehicle,

Identify any hazards or potential trouble,

Predict what might happen,

Decide on what to do about it ,

Execute your decision....

That's the S.I.P.D.E. method of pro-active driving.....if you are always vigilant and remember that anything can happen at any time, and you are always on task, you should develop habits to keep you safe on any roadway.....

So-

Check your mirrors often and when braking.

Scan intersections before you arrive.

Make your lane changes as straight as possible without oversteering.

Look well ahead, especially on high speed roads......