Undertaking on the motorway.
Discussion
dcb said:True, but a 5 lane carriageway should allow enough space for the numpties to use lanes 4 and 5 "because I always drive there", lane 1 for lorries and other limited vehicles, lane 2 for us (and frequently elephant racers) and most importantly lane 3, empty at all times!
Against this, building wider roads won't really help. There will still be a queue in the right most lane.
I don't think it's as black and white as you put it dcb.
If I'm in lane three going slower than I want, held up my the car in front, keeping a sensible separation, and lane three is consistently faster than lane two, and the gaps are lane two are only long enough for me to stay in that lane for a couple of seconds at my current speed before being bauled, why on earth would I move into lane two? It just guarantees that I will be boxed in to the line of slower traffic.
In that situation, it is possible for the car behind me to take a run up, dive into lane two, charge right up to the far end of the gap and trust that he's past me and able to pull out before he runs into the back of the next car in lane two. The reason this is possible is that I'm maintaining a safe separation and he isn't. The only way to absolutely prevent undertaking is to close right up on the car in front so it is not possible for the undertaker to pull out. Which is clearly stupid and dangerous. Just because it is possible to undertake somebody, doesn't mean it is safe or reasonable to do so, and doesn't mean they are in the wrong.
If I'm in lane three going slower than I want, held up my the car in front, keeping a sensible separation, and lane three is consistently faster than lane two, and the gaps are lane two are only long enough for me to stay in that lane for a couple of seconds at my current speed before being bauled, why on earth would I move into lane two? It just guarantees that I will be boxed in to the line of slower traffic.
In that situation, it is possible for the car behind me to take a run up, dive into lane two, charge right up to the far end of the gap and trust that he's past me and able to pull out before he runs into the back of the next car in lane two. The reason this is possible is that I'm maintaining a safe separation and he isn't. The only way to absolutely prevent undertaking is to close right up on the car in front so it is not possible for the undertaker to pull out. Which is clearly stupid and dangerous. Just because it is possible to undertake somebody, doesn't mean it is safe or reasonable to do so, and doesn't mean they are in the wrong.
I believe the issue here is weaving, not undertaking. Someone overtaking while leaving too little space is just as dangerous as someone undertaking with too little space.
Weaving is indeed dangerous, and most times pointless as well, since the weaver will most times only end up a few cars further ahead in the line. Granted, I'll do it on occasion when the usual New Jersey-licenses minivan in hogging the left lane and there's a line of traffic in the right, but I don't make it a habit.
Undertaking, on the other hand, I will do on a regular basis in the daytime. I don't know how it is in the UK, but here in the US if you are just completing a pass while in the left lane, the only way to get a left lane hog into the right lane is to come right up on their tail, which isn't the safest thing to do. Usually easier to underpass at speed and getting past them before they know what happened. At night it's significantly easier, as I just turn on my high beams while behind a left lane vigilante and keep them on until the asshole merges right. I've never had someone not let me pass at night...
But as far as the whole issue of speed differential is concerned, I've dealt with more than enough stupid drivers to know that the less time spent next to the person, the better. Self-righteous idiots do funny things when they realize a vehicle is about to pass them. Sometimes, especially with New Jersey and minivan drivers, they are in awe of seeing a shiny vehicle next to theirs, and their steering abilities suddenly fail as they begin to swerve over into my vehicle. Either that, or they feel they must race you, since hell, they were going 70 in a 65 and how dare anyone want to go faster! It's easier just to eliminate the wonder/decision and blow past 40mph faster. It's also much more fuel efficient to maintain a speed than to constantly slow down and speed up for such drivers. I've found it can mean a difference of 30mpg compared to 20mpg when constantly starting and stopping.
Weaving is indeed dangerous, and most times pointless as well, since the weaver will most times only end up a few cars further ahead in the line. Granted, I'll do it on occasion when the usual New Jersey-licenses minivan in hogging the left lane and there's a line of traffic in the right, but I don't make it a habit.
Undertaking, on the other hand, I will do on a regular basis in the daytime. I don't know how it is in the UK, but here in the US if you are just completing a pass while in the left lane, the only way to get a left lane hog into the right lane is to come right up on their tail, which isn't the safest thing to do. Usually easier to underpass at speed and getting past them before they know what happened. At night it's significantly easier, as I just turn on my high beams while behind a left lane vigilante and keep them on until the asshole merges right. I've never had someone not let me pass at night...
But as far as the whole issue of speed differential is concerned, I've dealt with more than enough stupid drivers to know that the less time spent next to the person, the better. Self-righteous idiots do funny things when they realize a vehicle is about to pass them. Sometimes, especially with New Jersey and minivan drivers, they are in awe of seeing a shiny vehicle next to theirs, and their steering abilities suddenly fail as they begin to swerve over into my vehicle. Either that, or they feel they must race you, since hell, they were going 70 in a 65 and how dare anyone want to go faster! It's easier just to eliminate the wonder/decision and blow past 40mph faster. It's also much more fuel efficient to maintain a speed than to constantly slow down and speed up for such drivers. I've found it can mean a difference of 30mpg compared to 20mpg when constantly starting and stopping.
RUSSELLM said:
I've no doubt there's motorists out there who think that distance should be 315 feet (legal), 200, 100 (like your self), 50 & a cars length (nutters) & there lies the problem.
We have a percentage of people, even on this small thread who think the highway code is wrong.
How can we ever expect everybody to drive the same ?
I thought that 315feet is the minimum stopping distance not the gap you should leave between yourself and the next vehicle....
jesusbuiltmycar said:
I thought that 315feet is the minimum stopping distance not the gap you should leave between yourself and the next vehicle....
315 feet is the distance quoted in the highway code for stopping distance from 70 mph to zero in dry conditions with good tyres and an alert driver.
For those of us not still living in 1965 with drum brakes and crossply tyres, the real distance in practice can be considerably shorter.
Many car magazines try this test on various cars, and produce much smaller numbers.
On the other hand, how often in practice do you need to drop all the way from 70 mph to a dead stop ?
Most of the time, you only need to drop to 50 mph or so to tuck in behind some slow moving traffic.
Isn't it about time [ 40 years] that the numbers were updated to reflect modern reality ?
And possibly a second set of figures for what happens in the rain.
dcb said:
Isn't it about time [ 40 years] that the numbers were updated to reflect modern reality ?
And possibly a second set of figures for what happens in the rain.
Dont be daft.
That would be educating the public and thats against current gov policy of "Keep em dumb and we can fine them for anything".
jesusbuiltmycar said:
I thought that 315feet is the minimum stopping distance not the gap you should leave between yourself and the next vehicle....
Should these two figures not be the same then ?
I must have missed this bit in the highway code when I took my test.
Pray, tell, what is the minumum gap between myself & the vehicle in front, whilst travveling at 70 mph ?
RUSSELLM said:
I thought that 315feet is the minimum stopping distance not the gap you should leave between yourself and the next vehicle....
Should these two figures not be the same then ?
I must have missed this bit in the highway code when I took my test.
Pray, tell, what is the minumum gap between myself & the vehicle in front, whilst travveling at 70 mph ?
Of course they shouldn't be the same. The car in front has to slow as well. It is not goiing to stop dead, no matter how good it's breaks are. This distance between your car and the one in front should allow you enough "thinking distance" (included in the 315 feet) to react + some margin of error.
If you drive on the continent sometimes they have chevrons marked on the road, with a sign showing that you should have a stopping distance with 2 chevrons visible between your car and the one in front. This distance is about 100-150 ft.
If your reactions are poor or your observation is poor then maybe you need 315ft.
Please stop causing tailbacks and apply some lane discipline.
Remember there is no "slow lane" on the motorway. The additional lanes over a single carraigeway are for overtaking only.
jesusbuiltmycar said:
Pray, tell, what is the minumum gap between myself & the vehicle in front, whilst travveling at 70 mph ?
If you try to apply 2 seconds gap in the dry nad 4 seconds in the wet then you won't go far wrong.
As said before the problem is caused by the general inability of drivers to establish safe following distances. How often does one observe that EVERY SINGLE vehicle is too close to the one in front, except oneself.
Personally I apply a rule that if I think I can drive in the lane to my left for longer than 20 seconds then I should be considering a move left. If definitely longer than 40 seconds then I'm in the wrong lane.
Flat in Fifth said:
Pray, tell, what is the minumum gap between myself & the vehicle in front, whilst travveling at 70 mph ?
If you try to apply 2 seconds gap in the dry nad 4 seconds in the wet then you won't go far wrong.
As said before the problem is caused by the general inability of drivers to establish safe following distances. How often does one observe that EVERY SINGLE vehicle is too close to the one in front, except oneself.
Personally I apply a rule that if I think I can drive in the lane to my left for longer than 20 seconds then I should be considering a move left. If definitely longer than 40 seconds then I'm in the wrong lane.
The same rules I try and abide byRUSSELLM said:
Pray, tell, what is the minumum gap between myself & the vehicle in front, whilst travveling at 70 mph ?
The necessary separation gap between you and the vehicle in front is NOT related to stopping distance. It is the safety margin you should allow to give time to react - the general rule is two seconds separation (minimum) in good conditions and three seconds or more in poor visibility.
Thus 180ft at 60mph is an adequate separation in good conditions.
The rule for setting a safe speed (my adaptation of Paul Smith's rule quoted on Safe Speed), which ties in with stopping distance, is "always be able to stop comfortably, on your own side of the road, in the distance ahead that you know to be clear and can reasonably expect will remain clear". At maximum braking effort, you should lose speed at approx. 20mph per second. Therefore, stopping distance at 60mph with emergency braking is 3 sec (average 30mph) equals approx. 130ft. So with comfortable braking (say half maximum effort), you should be looking for the road to be clear 260ft ahead at 60mph.
That may seem to contradict the two seconds rule but the way it ties in with separation distance is the qualification "and can reasonably expect will remain clear". If you're following a vehicle at 60mph and the road ahead of him is clear, you can be reasonably certain that it will not stop instantly (his shortest stopping distance is 130ft so the actual stopping distance you can reasonably expect to be available to you is 310ft). Thus the two seconds separation simply provides the time to react.
If you continuously review that rule, then as soon as something happens which means that you cannot reasonably expect the road to be clear, you will increase separation and/or reduce speed.
Flat in Fifth said:
If you try to apply 2 seconds gap in the dry nad 4 seconds in the wet then you won't go far wrong.
I agree with the principle of increasing separation in the wet but suggest that it is NOT on account of increased stopping distance, because that will apply equally to you and the vehicle in front.
However, a wet road is likely to be accompanied by reduced visibility because of rain or spray and increased risk of something unexpected such as car ahead skidding or taking evasive action. Those are the reasons why a longer separation is advisable and why longer separation is also sensible when visibility is reduced by mist or fog.
When on the highway, for following distance I also take into account what's to my left or right... In construction areas where there are concrete barriers on both sides, I'll leave a 3 or 4 second gap, but then where there is a grassy median and/or hard shoulder, I'll follow closer because I'll have somewhere to go if I need to stop suddenly...
SJobson said:
The car in front might stop dead if it hit something, however.
Well it all comes down to observation and prior planning on your part.
If you are of the numpty type of driver who only looks at the rear lights of the car in front then you will have no idea of what is happening on the road up ahead.
However, if you are a competent type of driver, you will be looking through the car in front, as well as maybe even 4-5 car further ahead, to observe possible hazzards in front and to anticipate when you will need to slow down or take some other form of avoiding action.
Which type of driver are you?
It's hardly suprising there's so much grief on the road, between the lot of us there's no agreement on how far to travel from the vehicle in front at 70 mph.
For what it's worth, the two second rule equates to 205 feet at 70 mph.
Try leaving two hundred feet gap on the motorway & see what happens
edited to add, Even more worrying is that there are people on the roads that think that it is physically impossible for a vehicle in front of them to come to an instant halt.
>> Edited by RUSSELLM on Wednesday 6th July 15:20
For what it's worth, the two second rule equates to 205 feet at 70 mph.
Try leaving two hundred feet gap on the motorway & see what happens
edited to add, Even more worrying is that there are people on the roads that think that it is physically impossible for a vehicle in front of them to come to an instant halt.
>> Edited by RUSSELLM on Wednesday 6th July 15:20
RUSSELLM said:
Try leaving two hundred feet gap on the motorway & see what happens
I do and nothing much happens. If the car ahead (or the car several places ahead) brakes, I usually have to do no more than ease off a bit. If it brakes firmly, I have plenty of time to react including (if I'm not already aware) assess whether the car behind me is at a safe distance and would be able to stop without hitting me.
Occasionally, a car may undertake and slot in ahead. If so, no big deal - I simply re-establish the two seconds gap. That may happen once a week or so, and I drive M25 every day J16-11.
dcb said:
NO NO NO !
If some car behind you has enough room to undertake you by using lane 2, then surely you should have been in lane 2 yourself ?
I can't abide those folks who form long queues in lane 3 when lane 2 is empty.
We drive on the Left in the UK, independent of what's in front of you.
More bluntly, if there's 200 meters of empty tarmac on your left, then you are in the wrong lane.
Sorry I dont understand the logic behind this. If I am travelling at 70 mph and on the road ahead there is for example lorry in lane 1, overtaking car in lane 2 (say at 60mph) and 2 cars in lane 3 overtaking lane 2 car at 65mph, I should then wait in lane 2 until the distance between me and the car I will ultimately overtake is less than 200m? Only then should I pull out to carry out my manouver? Why?
I think the fundamental problem with this proposition is that the next guy (who doesnt know your rules) driving at 68mph then rolls up along side me (and I am now doing 65mph to match the overtakers in lane 3) and proceeds to overtake me and block me in.
The way I do it (rightly or wrongly) is to watch what is happening behind me. If I am held up occasionally I will stay in lane 2 if I am already there and then merge with lane 3 as and when it is appropriate. At other times I will `queue` in lane 3 with the other traffic. However once clear of the obstacle if I see the car behind me wants to make more rapid progress I will let them pass as soon as I can (NOT when I have reached my cruising speed).
As I see it a large part of the problem is caused by people who want to cruise at say 80mph and they simply will not move over and let a faster vehicle pass if it means that it delays them getting to their target speed for even one second. So what happens is that they see a constantly approaching horizon of slower moving vehicles in lane 2 and refuse to pull over
to let other vehicles past as they dont see a gap big enough allow them to do it without modulating their speed. The situation is exacerbated when this is done by slowly accelerating vehicles who then take an age to get to their desired terminal velocity
RUSSELLM said:
Even more worrying is that there are people on the roads that think that it is physically impossible for a vehicle in front of them to come to an instant halt.
It is highly unlikely to happen without some warning (e.g. bunching or brake lights going on further ahead), in which case the "can reasonably expect will rmain clear" part of the safe speed rule comes into play. What circumstances can you describe where it could happen without any prior indication? An oncoming vehicle suddenly swerving and crashing head on? You can't make allowance for that sort of event.
Observer2 said:
An oncoming vehicle suddenly swerving and crashing head on? You can't make allowance for that sort of event.
Can't you ?
So what are the minimum stopping distances for in the highway code ?
Was it just to fill a page ?
Sorry for my ignorance, I'm confused
>> Edited by RUSSELLM on Wednesday 6th July 16:36
Gassing Station | Speed, Plod & the Law | Top of Page | What's New | My Stuff