RE: Safest distance between vehicles.?

Question

I"ve read 6 excellent answers to my ? and 1 stupid one. However, my question still hasn"t really been answered. I asked "What is the safest MATHEMATICALLY distance between 2 vehicles traveling at 55 m.p.h.?". The 3 sec. rule, or the car-length rule? Assume both vehicles are similarly equipped.

Answer 1

Three seconds.

Answer 2

Driver's Manual recommends a minimum 3-second following distance between your vehicle and the vehicle ahead of you.

This rule applies to passenger cars and light trucks traveling in ideal conditions.

When conditions are less than ideal, you must increase the amount of distance between you and the vehicle ahead of you.

Answer 3

I was taught in driver's ed. in high school........ 1 car length per 10 mph.  example 70mph. 7 car lengths.

Answer 4

Three second rules works for all speeds.  As the vehicle in front passes a mark, count.  If you get to 3 or better before you pass the mark, you are okay.  If not, increase the distance.  Also when stopped behind another vehicle, make sure you can see both rear tires which will tell you that you're far enough back to avoid hitting them should you be hit.

Answer 5

definately the 3 second rule. No matter how fast either car is going or the performance of the car.  If you keep a 3 second cushion between you and the car ahead you will be much safer.   3 second rule-- When the car ahead of you passes a stationary object start counting seconds.  When you pass that same stationary object stop counting and you will know how many seconds behind you are.

Answer 6

your are traveling at 10.9 feet per second = one hundred and nine feet

Answer 7

Much safer at 4 seconds.  Even at 3, if the reaction time of the driver ahead is faster than you, and the tread depth is a little better than yours, you have a chance of rear-ending him in an emergency stop.  One car length per 10 mph is going to be pretty close to the 3.5 second mark, but it is hard for the average person to guage car lengths.  The car length rule was also established when full -size cars were a lot larger.  10 lengths of a 1958 Chevrolet is a lot different from 10 lengths of a 2001 Camry.  The 2-second rule touted in some manuals really only is safe if you and the driver in front are both graduates of a performance driving school, no matter what anybody else says.  Why?  the AVERAGE reaction time is just over 2 seconds.  Remember, to get that average, some have a 1.5 second reaction, but some have a time closer to 4 seconds.  If that person is you, or the person behind you, guess who is going to be in an accident?

Answer 8

It's 2 sec rule in day time and 4 sec in the night time.

Answer 9

60 mph is 88 feet per second, so you travel 264 feet in 3 seconds if you're going 60 mph.  A car length is about 16 feet, so 264 feet is almost 17 car lengths -- a lot more than a car length for every 10 mph.  A nice way to look at it is to decide how much time you want to give yourself to respond to something immediately ahead.  I use the 2-second rule in clear, dry conditions.  If someone is following me too closely, I leave more room in front, to reduce the chance that I might have to make a sudden maneuver.

Answer 10

The 3 second rule gives you more room.

1 car length per 10mph would be about 15' X 6 (60mph) = 90'

60mph = 88' per second.  3 seconds of distance gives you

triple the time to react.  55mph X 5280' / 3600secs = 80.6 fps

80.6 X 3sec = 242 feet for the 3 sec rule

15' X 5.5 = 82.5feet for the car-length rule (and many cars are

not even 15' long).  The SAFEST distance is obviously the

greater distance.  In order for 82 feet at 55mph to be safe,

you would have to be paying full attention ALL of the time.

If your reaction time exceeded 1.02 seconds, you would

collide with the car in front of you.  If you're paying attention,

your reaction time would be about 0.6 seconds....less than

a half-second margin for error.

Answer 11

I'd go with 3 seconds = 3seconds is always 3 seconds a car length can vary quite a bit

Answer 12

The 2-3 second rule is the best in my opinion. The reason is that the distance is directly tied to the speed the vehicles are traveling.  The higher the speed, the greater the distance. When in doubt, add a couple seconds and increase your reaction time.  In bad weather, add another couple seconds. I drive semi trucks for a living, and generally use a 6 second rule on good roads.

Answer 13

There are 2 unwritten rules regarding this matter, both of them can be found in the NYS Driver's Manual, but neither of them is actually printed into law.

The 2 rules are: either 1) 2-second rule (determine a fixed object and see if you can count to 2 while following another vehicle - if you do you're too close) and 2) 1 car length for every 10miles per hour on that roadways speed sign (in NYC highest speed is 50 mph - so 5 car lengths).

Both of these "theorems" should be expanded in the event of bad weather or operating a motorcycle or truck/tractor-trailer.

Unfortunately, neither of these explanations is used in the NYS Vehicle & Traffic Law pertaining to Following too Closely (tailgating).

Answer 14

The car length rule, and I don't have time to do the math, I have to go to church. GOD BLESS ....:0)