Speeding

[alastairq]

although being more economical is of course a nice plus.

 

a side-effect that, although minimal in itself, does contribute to an overall improvement.

 

To simplify the matter, with a car, it's all about using the minimum steering lock [amount one turns the steering wheel] to achieve an objective....and to start straightening up as soon as available road width allows... gentle, even steering reduces tyre wear, reduces steering wear, reduces the risk of a loss of control through abrupt steering, makes things smooth .....and is appreciated by passengers...especially of the in-law variety, whilst at the same time, allowing, if wished, maintenance of higher speeds through the bends.....

 

So many drivers don't even think about that.....relying instead on hugely wide [and unnecessary] tyres, fancy suspension, and hyperactive sales bumph.

[Debs.]

All this chatter about 'physics', 'speed', 'control' and 'skill' seems to have a feint-whiff of bravado and complacency............it`d (surely) all seem so very different if the fireman were cutting you (and those dear) free from the wreckage that was once your car, or you were watching somebody being placed in a body-bag: directly because of your actions.

 

So many years ago: my actions resulted in the death a dog (when I was 17).....I was riding a motorbike, going too fast for the urban-road situation, but at the 30 mph speed limit........children teasing dog on pavement.......dog bolted into road........millisecond to react......insufficient time/distance.......dog horribly killed........my responsibility; never forgotten!

 

...........I don`t speed; and yes I do often drive (well) below the posted limit where there is proximal-danger `twixt vehicles and lives.........if that annoys and frustrates you, then I truly-hope you never cause the death of another.

[DDolfelin]

Well said, Debs.

There are many places where to drive at 30mph is downright dangerous.

Parked cars obscuring one's vision of anyone under 4 feet is a case in point.

 

Many single track rural lanes here with the obvious dangers of totally blind bends further obscured by hedges etc.,.

The scarcity of traffic increases the danger.

What is coming around the bend towards the speed merchant?

Horses, tractors, milk lorries, oil tankers, ramblers - or some other speeding idiot perched in their 4x4?

[beast66606]

Which bit? the physics of two relatively equal masses colliding is extremely well known and has even been demonstrated on TV.

<snip>

 

Weight and mass aren't the same thing for a start and mass X velocity = momentum (or kinetic energy) not force, force was always mass x acceleration when I did applied maths / physics.

 

The chances of two identical, in every way (including fuel, passengers and luggage, engine mounting bolts etc. etc.), cars meeting in an exactly square collision (to ensure no deflection) is about as likely as anyone trying to justify speeding on some ridiculous notion and succeeding.

 

So one of the cars will come off worse, how worse will depend on lots of factors.

 

But we are wandering from the basic premise that the speed limits are there for everyone to obey, like them or not.

[Tony_S]

I was thinking something similar to Debs that all this stuff about racing lines and perfectly elastic collisions etc was detracting from the point about safe driving. I used to hear all the racing stuff from the headteacher at a school I worked at. He used to drive past me (and everyone else) in the morning. He would after all his aggressive driving usually just be opening his car door as I entered the staff car park.

Sometimes motoring incidents do leave an impression on those who survive. Some friends were returning from a shopping trip along a single carriage A road. From the traffic opposite, a motorcycle pulled out and accelerated towards them. Due to the road all my friend could do was brake as much as possible when it was clear the biker had no intention of returning to his side of the road. My friend was in no way to blame but when someone uses your vehicle as their suicide it still left all those "what if I ..." questions.

 

My father used to always make us aware of places where he saw possible "dangers" on the road. I think he was trying to make us into considerate road users. It turned out later that he had killed a child years before. This thread has at times veered towards there are no accidents and everything is avoidable with technique. Sometimes the unexpected doesn't have to be as odd as a tank falling off a Chinook.

[cutting42]

Weight and mass aren't the same thing for a start and mass X velocity = momentum (or kinetic energy) not force, force was always mass x acceleration when I did applied maths / physics.

 

The chances of two identical, in every way (including fuel, passengers and luggage, engine mounting bolts etc. etc.), cars meeting in an exactly square collision (to ensure no deflection) is about as likely as anyone trying to justify speeding on some ridiculous notion and succeeding.

 

So one of the cars will come off worse, how worse will depend on lots of factors.

 

But we are wandering from the basic premise that the speed limits are there for everyone to obey, like them or not.

 

I am aware that Mass and weight are different but for this example they are effectively the same. Knew I shouldn't try to quote sums late at night, the quote I used was slightly off in its terminology but the principle is the same. The impact on both cars would be shared between them in a ratio of how different the masses are. Car vs truck and the car will be much worse off as the track has more mass, car vs car and the damage would be more equally shared. The impact angle, deflections, engine bolts? or avoiding actions would only affect the total energy released, not how it is shared.

 

Also in no way was I trying to use the above to say speeding was OK. It was just a footnote to the "closing speed" comment as it is one of those urban myths that I thought might be interesting to any who had not realised it as I found it fascinating when I had it explained to me originally.

 

I agree we have drifted from the main premise of the OP but I found it interesting.

[Talltim]

One thing to remember is that exact speed limits are arbitrary. For example if we had gone metric our limits would all be in whole numbers of kph

Not advocating breaking the law, just pointing that out

[cutting42]

One thing to remember is that exact speed limits are arbitrary. For example if we had gone metric our limits would all be in whole numbers of kph

Not advocating breaking the law, just pointing that out

 

Spot on and well pointed out. This is why driving to the conditions and not the limit is important. Where the discussion is at its most interesting is when the conditions allow higher limits than are legally permitted.

 

*** Just to make sure no one get the wrong end of the stick here, the rest is just a discussion not an advocation of rule breaking ***

 

It can be argued that the limit should be your ability (and the vehicles) to slow or avoid any potential hazards in view at any time (there is an official phrase that goes along the lines of not causing another vehicle to hit, swerve or change direction). Theoretically if you can see 1/4 mile in all directions you would be safe travelling at any speed that would allow you to stop within that area. However you need to account for other vehicles also travelling under the same assumption. If someone was travelling towards you at 60 mph then you would both have 15 seconds to see each other, avoid or stop in plenty of time. As you drive faster, say 120mph (to keep the sums simple) you reduce this time to 7.5 seconds but of course the car takes longer to stop and you may be at a point, depending on your and the cars capabilities to not be able to stop or avoid in time.

 

The balancing of these factors is a skill that can be learnt through experience and education. There are many real world influences like for the most part we have separate lanes and most people drive in those lanes but we should drive as if around the next corner someone will be in the wrong lane. Clearly we cannot assume everyone has these skills and self control to judge the conditions correctly so we have speed limits which is as it should be.

 

I believe that all roads go through an official assessment to determine the limit and there are many case studies and prior analysis that help them do this but they are clearly set for the lowest common denominator - in fact they kind of have to be. This lowest common denominator is probably a learner or novice driver but could also be an elderly person or just the truly incompetent. The result is a speed limit that is conservative, also it is a number and it can be easily measured and thus has become the key headline factor in many campaigns. It is much harder to measure "skill" or ability behind the wheel and certainly a camera cannot judge although an experienced traffic cop or similar can spot a good driver in seconds.

 

Once we (as a nation) start issuing "limits" we inherently take some responsibility away from the driver and as a whole, people assume that as they are within the speed limit they are "safe". My point is and has been for many years that speed regulation is but one part of safe driving and not even the most important part IMO.

 

It is encouraging to read many on this thread talking about their own careful habits, clearly you are a very atypical section of the driving public as evidenced by what I see every day.

 

alistairq quote - To simplify the matter, with a car, it's all about using the minimum steering lock [amount one turns the steering wheel] to achieve an objective....and to start straightening up as soon as available road width allows... gentle, even steering reduces tyre wear, reduces steering wear, reduces the risk of a loss of control through abrupt steering, makes things smooth .....and is appreciated by passengers...especially of the in-law variety, whilst at the same time, allowing, if wished, maintenance of higher speeds through the bends.....

 

Loved this, absolutely spot on and exactly what I try to do all the time, nice description. In addition it is what is taught by many racing schools as it is invariably the quickest way around a race track. Jackie Stewart the racing driver used to have a driving school where they had a car with a large bowl fitted to the bonnet. Into the bowl they would put a bowling ball and the student would then try to match the time around the track that Jackie Stewart set without the ball rolling out of the bowl.