why is undertaking illegal?

[joko]

genuine question and just curious... it seems it is really just the manouvre of an overtake, but on the other side... so why is it so bad?

i know it is illegal so i dont need the legalities, just the actual reason why it was made illegal - why is it dangerous or bad etc?


been on the motorway a lot last few days and witnessed a few people do them, and couldnt really see a problem... they got round the person they wanted to easily enough, and perhaps its better than a bit of intimidating road rage tailgating?

or am i missing something?

thanks

[ChuckFickens]

Undertaking equates to weaving through traffic, which is highly dangerous. Passing on the inside is allowed however.

[joko]

yes but so is overtaking then isnt it?
isnt it really just changing lanes a few times? as you would with overtaking?

i know some believe undertaking is simply going faster than the person to their right, but thats just lane speeds... the speed limit is the same for all lanes.

[ummmm]

Because you'd have people over taking on either side.

They'd be loads more crashes if it wasn't a road rule.

[ummmm]

These rules are for a normal flowing motorway.

'Passing' as you might do in slower moving traffic are not taken into consideration.

We have no control over the speed of the other lanes.

[joko]

why would people crash more?
i assume they would execute the same level of care as when overtaking etc, people are either careful or theyre not regardless of the manouvre they are doing ...so why would they crash more?

the manouvre of undertaking really involves 2 actions - changing lanes to the right, then changing lanes to the left - well we do those two actions all the time - in overtaking and in simple basic lane changing - except in a different order...

so i honestly dont understand why its dangerous if you change lane to the left first, then the right... the only thing that is different is the order you do them in...isnt it?

[B00]

i can think of two reasons, possibly both incorrect (I don't drive) but I'll throw them out there anyway.

1- one is the one ummm suggested, if undertaking was allowed on both sides, it could get nasty!

2- Perhaps a chance, albeit slim, of mounting pavements and mowing down pedestrians?

[joko]

ummm, im not talking about the speed of other lanes, or passing...just the actual manouvre of undertaking

[jackthehat]

Any driver of a vehicle has the expectation that the 'faster' traffic will be to their RHS.
If I am travelling in the middle-lane of the M6, I am aware of any vehicles I have passed in the Slow-lane; I can 'clear' that lane by a glance to my left/wing mirror/r-v mirror before I move over.
To start the manoeuvre only to find out that I had been under-taken by an impatient driver and instead of moving into an empty lane, I have either a narrowing gap of a vehicle precisely where I intended to place my car will lead to me taking instinctive evasive action which, in turn will confuse anyone else behind or alongside me.

[LazyGun]

I had always thought that it was as simple as the fact that to have a vehicle passing you on your offside would be unexpected, given that the rules of the road state that you should only overtake on the right.

Given that it might, for many motorists, be an unexpected maneuvre, it seems likely that you might see a greater number of accidents.

On the other hand, I dont know when the rules of the road were first thought up, but years of motorway driving mean that almost everyone at some time or another has "undertaken" - it is an almost inevitable consequence of motorways and the traffic flow.Perhaps the rules should be updated to better reflect modern practice and road use.

[joko]

how do you mean 'nasty' boo? i think it gets nastier when people start getting aggressive and trying to get people out of their way.

you are allowed to undertake when the car in front is turning right - if the danger of mounting the kerb was an issue this would be not be allowed surely

anymore than the danger of an overtaker straying into the opposite lane is an issue... i think people generally can control their cars enough not to mount the kerb...

it seems that the actions involved in the manouvre are allowed in other circumstances - so they cannot be that dangerous - just not when it is labelled an undertake...

if going around a vehicle was so dangerous, it would not be allowed on eiher side would it?

[ladybirder]

It's not illegal.

http://en.wikipedia.o...Undertaking_(driving)

[Zeuhl]

There should be no space for undertaking anyway

Because traffic in front of you should be keeping to the left unless turning right

It's simple if all the rules are complied with

[heathfield]

Undertaking is permitted on one-way systems. "Drivers on a oneway system should be aware of traffic overtaking on their left" used to be a warning in the Highway Code. Since each carriageway on a dual carriageway or motorway is a oneway system, undertaking is not strictly illegal. it is simply discouraged. And, as I heard a Chief Constable say in a radio interview on undertaking, "In the event of an accident, this would be taken into consideration."

[joko]

jack the hat - there is no 'slow lane'... it is only a slow lane if there is a slow moving vehicle ion it... if not the speed limit is the same

also the scenario you state, could that not apply to an overtake too? you plan to move across and a car overtakes - same thing isnt it?

isnt that person just changing lanes to the left, same as you?

i realise how the law stands now, people may 'expect' things - but you really shouldnt expect anything on the road, and excercise uptmost care...
but they only expect things because the law says its not allowed - if it was legal, people would learn to expect it...same as you do the other way round...

i would never just change lanes becasue i 'expected' it to be ok...people do still undertake all the time, legal or not

[Zeuhl]

people do still undertake all the time, legal or not

Really?

Other than on motorways i think it is very rare except in congestion on multi lane carriageways which is not 'overtaking' or 'undertaking' anyway

[joko]

lazy gun - but cars pass on the eft all the time.. thats not undertaking...thats just a faster moving lane, so you should always expect cars on your left

it is only an 'unexpected' because its illegal - if it was legal it would be expected, right?
so where the danger of the actual manouvre?

also what constitutes an undertake? whats the differnce, technically between simply 2 lane changes in close succession, and an undertake?

is there a kind of distance or time limit it must be before it becomes two separate manouvres?

[jackthehat]

The motorway lanes, historically, have always been; Slow-lane, Fast-lane and Overtaking Lane. The speed limit is the same for all 3, but that is *not* the speed at which all vehicles should be travelling in those lanes, but the maximum permissible in ALL of them.

As I said, convention dictates that passing is completed 'on the right'....that is what Learner Drivers are taught when they set out to drive and has been everthus since the advent of motor-driving.

There is precious little 'proper' reason for undertaking on a motorway.

[jackthehat]

You didn't learn terribly much on your 'Drivers Awareness' course, did you, doc?

[joko]

yes zeuhl people do do it ...i myself was 'agressively' undertaken about 3 times in about the space of 5 days...did a lot of driving around and on every occasion was doing the maximum speed limit - hence me asking the question