Gaps between cars
Discussion
After a post earlier today and something that has been niggling me for a while...
I try (though I don't always manage) to keep a 2 second gap between cars, roughly. However, compared to almost every other car out there (sunday am/other quiet times aside) the gap in front me me seems to be several times larger than EVERY other car out there.
Am I going insane? Is my math subject to an old-age brain-fade moment? Am I leaving too big a gap? @70 it will be around 60 meters: Based 1mph = 0.44 meters/s and two second intervals between fixed landscape points.
I'd say the average gap between others front/rear bumpers is closer to 10m-15m on average (Possibly slightly more as it can be hard to judge accurately but it is FAR less than my own.
Another poster here suggested the 2 secs is for a dry motorway@70, to which I didn't realise and on checking, the HW code merely states "faster-moving", which is a bit ambiguous. I must admit since distance is relative to time & velocity I assumed 2 secs was the universal rule since even at slower speeds, it allows you closer.
Perhaps my experiences are somewhat uncommon, I don't know.
I try (though I don't always manage) to keep a 2 second gap between cars, roughly. However, compared to almost every other car out there (sunday am/other quiet times aside) the gap in front me me seems to be several times larger than EVERY other car out there.
Am I going insane? Is my math subject to an old-age brain-fade moment? Am I leaving too big a gap? @70 it will be around 60 meters: Based 1mph = 0.44 meters/s and two second intervals between fixed landscape points.
I'd say the average gap between others front/rear bumpers is closer to 10m-15m on average (Possibly slightly more as it can be hard to judge accurately but it is FAR less than my own.
Another poster here suggested the 2 secs is for a dry motorway@70, to which I didn't realise and on checking, the HW code merely states "faster-moving", which is a bit ambiguous. I must admit since distance is relative to time & velocity I assumed 2 secs was the universal rule since even at slower speeds, it allows you closer.
Perhaps my experiences are somewhat uncommon, I don't know.
I also try to keep a 2 second gap (around town, on motorways, anywhere but the track!), and I agree that the majority of people appear to keep a gap of around a second or even less. I'm not sure exactly what the highway code says, (maybe I should check!) but sometimes 2 seconds seems big, usually after driving on the motorway for some time and I guess it's just becoming accustomed to the speed. Around town, 2 seconds can be quite close to the car in front and I sometimes adjust for more to allow for unforseen circumstances.
All in all, I don't think it's age-related brain fade but more likely people feeling a little too safe in their metal boxes!
Sorry for waffling!
All in all, I don't think it's age-related brain fade but more likely people feeling a little too safe in their metal boxes!
Sorry for waffling!
Can you honestly say you see most drivers observing anything LIKE that distance though? I'd say honestly that half that is about the upper limit to what I see.
I'll fully concede it may be distorted by driving position/moving etc and everyone is far enough away, but I will be surprised if that is indeed the case.
I'll fully concede it may be distorted by driving position/moving etc and everyone is far enough away, but I will be surprised if that is indeed the case.
Top Gear proved that those old stopping times are well out of date unless you happen to have an old Ford Pop
Reaction times from seeing to brake pedal application do vary a lot
A 20 year old can react much quicker than me at age 50+
As a 50+ driver I SHOULD have the experience over that 20 year old which SHOULD allow me to see any potential incident before they do an therefore be on the brake pedal sooner than they are
Reaction times from seeing to brake pedal application do vary a lot
A 20 year old can react much quicker than me at age 50+
As a 50+ driver I SHOULD have the experience over that 20 year old which SHOULD allow me to see any potential incident before they do an therefore be on the brake pedal sooner than they are
bulldog5046 said:
I've always believe its simply because the Highway code was written in the 50's and never updated.
from 60mph i expect a modern car could stop in 30meters, thinking distance is apparently 18meters but i have my doubts over that aswell.
What modern cars are capable of and what the average motorist is capable of are not the same thing. I believe crash investigators (any reading this please feel free to correct) will add 1.5 seconds worth of reaction time when calculating speed after a smash. That's about double the HWC thinking distance at 70mph. Now consider the average motorist being prepared to slam the anchors on at 70/80. It probably won't happen and even if they do, many will back off the brakes when it starts to judder (yes after 30 years or so many drivers don't have a clue about ABS). Suddenly a 2-second gap doesn't sound too excessive. After all even the most alert driving god can't stop the vehicle coming up behind.from 60mph i expect a modern car could stop in 30meters, thinking distance is apparently 18meters but i have my doubts over that aswell.
7mike said:
After all even the most alert driving god can't stop the vehicle coming up behind.
So true and is why part of advanced driving is to allow for the numpty behind when considering what gap to leave in frontThe using of lane lines is useful for that
With each being 10 mph then driving at 50 with 5 lines in front but only 3 behind means that the front needs to be increased by 3 lane lines to 8 lines
sounds daft but it does work as a general easy way of keeping to the minimum
Of course there is no accounting for the non concentrating driver behind whatever the situation!!
What I have observed is that, in free flowing traffic, most drivers leave the same gap, whatever the speed limit.
What is adequate, although often not enough at 30 mph, is nowhere near enough at 70 mph or more.
Contolling the gap to the front and behind is your primary means of safety, related to your observation of course. Relating that position to those in other lanes on multi lane roads is harder but should be attempted.
"Safety bubble", is the expression often used.
It does means yielding to those who fill that gap though.
Most times, on most busy roads, it'll not make much difference to journey times.
Don't get hung up on stopping distances, it's thinking distance that counts.
Space = thinking time, because there might be an "escape" route for you.
What is adequate, although often not enough at 30 mph, is nowhere near enough at 70 mph or more.
Contolling the gap to the front and behind is your primary means of safety, related to your observation of course. Relating that position to those in other lanes on multi lane roads is harder but should be attempted.
"Safety bubble", is the expression often used.
It does means yielding to those who fill that gap though.
Most times, on most busy roads, it'll not make much difference to journey times.
Don't get hung up on stopping distances, it's thinking distance that counts.
Space = thinking time, because there might be an "escape" route for you.
james_gt3rs said:
R0G said:
A 20 year old can react much quicker than me at age 50+
Is there really much difference then?Then, reaction in a 20 year old will not have the experience and learning of a 50+ year old.
Then, why the fixation on reaction time for public road driving?
Competition driving, it might matter.
However, if anyone is driving on public roads based upon their reaction time, they should not have a licence.
The problem with most people's perception of an adequate gap is that they are not expecting the vehicle in front to come to an abrupt halt. At the very worst, they are thinking (subconciously in most cases) that if the car in front slams on its brakes, they will be able to do the same. However, if there is a multiple accident, such that the car in front slams into the back of the queue and comes to a dead halt, then there is no way that you will stop if your gap was only a second or so.
This was brought home to me a year or so ago when following other traffic in lane 3 on the M4. Suddenly and without any prior warning, there was a car stopped in the central barrier but sticking out into the lane and with people getting out. The experience of driving in a perfectly 'normal' way at around 70mph to having to a) register that there was a problem, b) react, and c) take action to check mirror / steer left / take account of the traffic in front braking hard, all reinforced that thre is no substitute for leaving a good large gap! 70mph suddenly felt like a very fast closing speed.
If people all left a proper 2 second gap, I'm convinced that 90% of motorway accidents would never happen. Trouble is, there's no denying that it's really hard to leave such a gap when traffic is heavy and cars keep on moving into your space, leaving you with the feeling you're going backwards.
Anyway, got to head out around the M25 now to pick up my daughter from Gatwick. Wish me luck with my space management!
This was brought home to me a year or so ago when following other traffic in lane 3 on the M4. Suddenly and without any prior warning, there was a car stopped in the central barrier but sticking out into the lane and with people getting out. The experience of driving in a perfectly 'normal' way at around 70mph to having to a) register that there was a problem, b) react, and c) take action to check mirror / steer left / take account of the traffic in front braking hard, all reinforced that thre is no substitute for leaving a good large gap! 70mph suddenly felt like a very fast closing speed.
If people all left a proper 2 second gap, I'm convinced that 90% of motorway accidents would never happen. Trouble is, there's no denying that it's really hard to leave such a gap when traffic is heavy and cars keep on moving into your space, leaving you with the feeling you're going backwards.
Anyway, got to head out around the M25 now to pick up my daughter from Gatwick. Wish me luck with my space management!
gdaybruce said:
Trouble is, there's no denying that it's really hard to leave such a gap when traffic is heavy and cars keep on moving into your space, leaving you with the feeling you're going backwards.
That's then about "Mind Driving".Take the rational, not "feeling" approach.
The "feeling" approach is why you see so many who are "digital" on the accelerator and brakes.
roachcoach said:
...I must admit since distance is relative to time & velocity I assumed 2 secs was the universal rule since even at slower speeds, it allows you closer.
The thinking distance element will be directly proportional to speed, but the braking distance part of it is more complex. The brakes have to dissipate the kinetic energy of the vehicle, which increases with the square of the speed.The Two Second Rule can only ever be an approximate guide, but in most circumstances it works pretty well.
WhoseGeneration said:
gdaybruce said:
Trouble is, there's no denying that it's really hard to leave such a gap when traffic is heavy and cars keep on moving into your space, leaving you with the feeling you're going backwards.
That's then about "Mind Driving".Take the rational, not "feeling" approach.
The "feeling" approach is why you see so many who are "digital" on the accelerator and brakes.
I am easing off for safety
- surprising what a good psychological effect that has
2 secs rule as much as possible.
Not only avoids accidents but also allows for better overatking (usually more view around the vehicle in front) and smoother, more economical (inc less wear and tear on brakes etc) driving due to being able to just slightly adjust throttle instead being on and off throttle and brakes.
And if every other bugger did it, it'd be a lot easier to get past the queue of sheep following the slow 'un by picking them off in ones and twos
Not only avoids accidents but also allows for better overatking (usually more view around the vehicle in front) and smoother, more economical (inc less wear and tear on brakes etc) driving due to being able to just slightly adjust throttle instead being on and off throttle and brakes.
And if every other bugger did it, it'd be a lot easier to get past the queue of sheep following the slow 'un by picking them off in ones and twos
defblade said:
2 secs rule as much as possible.
Not only avoids accidents but also allows for better overatking (usually more view around the vehicle in front) and smoother, more economical (inc less wear and tear on brakes etc) driving due to being able to just slightly adjust throttle instead being on and off throttle and brakes.
And if every other bugger did it, it'd be a lot easier to get past the queue of sheep following the slow 'un by picking them off in ones and twos
Absolutely, I'm continually shocked at how people in front (I know this is mentioned many times on PH) apply the brakes because they are too close to the car in front which either gently applied the brakes or simply is going round a slight bend.Not only avoids accidents but also allows for better overatking (usually more view around the vehicle in front) and smoother, more economical (inc less wear and tear on brakes etc) driving due to being able to just slightly adjust throttle instead being on and off throttle and brakes.
And if every other bugger did it, it'd be a lot easier to get past the queue of sheep following the slow 'un by picking them off in ones and twos
Basically I don't need to do this as if I leave a safe gap, two seconds is a good rule of thumb for this, you can see that he is applying the brakes for no reason other than he is simply too close to the car in front, and cannot see beyond that. I simply lift off the throttle and put my foot close to the brake just in case. This much more efficient as you correctly stated.
This is especially prevalent in roads such as the A14 to and from Cambridge, where tail-gaiting is a massive issue as has been discussed on PH and country roads such as the A47.
If people kept a safe distance (and stay in the correct lane!) then there would be no issues. But as we all know this is not the case.
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