Optimal speed for economical m'way driving?

shown73

This is a discusion without end. The head bangers and "experts," will never be convinced, but for what it's worth, I found out long ago that the most important thing is average speed on a journey, not how fast you can go in bursts. This was reinforced sometime later by an article I read written by Stirling Moss, who was writing about competing in the Mille Miglia. In effect he said exactly the same thing, he was more concerned about his average speed than outright speed, and a skilled driver in a slower car could still win. Its actually more difficult to do this than simply flooring it whenever you get the chance. Any idiot can do that. Good fun, perhaps, but this is a money saving site, isn't it?

tomstickland

As with all money saving, it's about putting a value on various things and deciding what you want. If you want to use the least fuel possible, then the basic physics says that low speeds are best. However, it is necessary to consider the risk from faster traffic and that a good figure can be obtained at a certain speed. You might decide that you don't mind spending a few percent more on fuel and save some time.

greenman7

Useful information from the Institute of Advanced Motorists website:

Obey the speed limits . Try to "feather" the throttle as you reach your cruising speed. Doing 56mph uses 25 per cent less fuel than 70mph and a smoother driving style can bring significant fuel saving. But never coast to save fuel; vehicle control must not be compromised.
Develop a sensible driving plan and endeavour to avoid a very tight driving schedule, with business and domestic commitments. Try to avoid driving under pressure or stress. Do not take a chance at the red lights, exceed speed limits, or cut corners. Allow an extra five minutes for each journey.

Chance of driver being involved in an accident
For every 1 mph reduction in a driver’s speed, the chances of being involved in a crash decrease by 5%. (source: Transport Research Laboratory)

Pew_Pew_Pew_Lasers!

greenman7 wrote: »

Chance of driver being involved in an accident
For every 1 mph reduction in a driver’s speed, the chances of being involved in a crash decrease by 5%. (source: Transport Research Laboratory)

So if I do 50mph rather than 70mph then I have no chance whatsoever of being in an accident on the motorway? Great!

:rotfl:

greenman7

I was a also bit confused by Chance of driver being involved in an accident
posting on the Institute of Advanced Motorists website.

I was also abit confused by the posting Obey the speed limits etc. As an Institute member you have already told us, quotes:
Balls to the speed limit. Its a number on a stick, nothing more. It tells you nothing about safety.
Speed limits are lowest common denominator safety enforcement - and achieve little, if nothing.
What has your accident got to do with speed limits? I'll go as fast as I feel is appropriate thanks.
Speed limits are there for a reason - mostly political. Obeying a number on a stick does not guarantee safe driving, it simply turns people into sheep.

So I am equally confused about both quotes - maybe it is time to contact the IAM for clarification?

The_Undercover_ADI

In many years of driver training (IAM, RoSPA, Cardington, DSA, Fleet, ORDIT, LANTRA, MSA experience), I have had chance to observe thousands of drivers, hundreds of response and advanced drivers 10's of racing and rally drivers and my conclusions are:

1. The ones who suggest that the speed limit is a number on a stick are the ones who neither understand the reason behind the number, nor are capable of ignoring it in a safe manner. The finest drivers I have ever met have taken great care in noticing and understanding the speed limit system, never ignoring it and only breaking the law when necessary and with all of the caution needed to do this safely. I have only met 3 drivers who I feel do this well - 2 police pursuit trainers, and a special forces close protection officer.
2. Individuals who regularly break the limit for their own reasons invariably drive with less consideration for other road users - either intentionally or simply because the increased speed means less time for observation and anticipation.

If you are in that much of a rush then you need to sort your life out - risking other people's lives and peace of mind simply because you can't organise your journey properly goes against the first rule of advanced driving - Plan Ahead.

cyclonebri1

The_Undercover_ADI wrote: »

In many years of driver training (IAM, RoSPA, Cardington, DSA, Fleet, ORDIT, LANTRA, MSA experience), I have had chance to observe thousands of drivers, hundreds of response and advanced drivers 10's of racing and rally drivers and my conclusions are:

1. The ones who suggest that the speed limit is a number on a stick are the ones who neither understand the reason behind the number, nor are capable of ignoring it in a safe manner. The finest drivers I have ever met have taken great care in noticing and understanding the speed limit system, never ignoring it and only breaking the law when necessary and with all of the caution needed to do this safely. I have only met 3 drivers who I feel do this well - 2 police pursuit trainers, and a special forces close protection officer.
2. Individuals who regularly break the limit for their own reasons invariably drive with less consideration for other road users - either intentionally or simply because the increased speed means less time for observation and anticipation.

If you are in that much of a rush then you need to sort your life out - risking other people's lives and peace of mind simply because you can't organise your journey properly goes against the first rule of advanced driving - Plan Ahead.

:T :T :T :T

tomstickland

The ones who suggest that the speed limit is a number on a stick are the ones who neither understand the reason behind the number,

So, how much more dangerous is 80mph vs 70mph on an empty motorway?
Personally I always know what the limit is for a section of road, I carefully consider why it might be there and also routinely choose to exceed limits.
Suggesting that in doing so I don't understand why the limit is there is incorrect.
For example, there's a new 40 limit on an A road near me and it's there because there's a T junction. However, the 40 limit then continues on for about 1 mile along perfectly straight A road. If there are no pedestrians on the pavement or bikes etc then I do feel any guilt over travelling at 50 indicated along there.

cyclonebri1

tomstickland wrote: »

So, how much more dangerous is 80mph vs70mph on an empty motorway?

Its probably no more dangerous or minutely more on an empty motorway.

But it's the numpties that don't know the difference between a dry empty motorway and a congested wet typical Friday afternoon that cause the problems.

I don't think you can give folks the choice given the number of ****** about

tomstickland

greenman7 wrote: »

Chance of driver being involved in an accident
For every 1 mph reduction in a driver’s speed, the chances of being involved in a crash decrease by 5%. (source: Transport Research Laboratory)

I'd have to see the report in more detail. It's very easy to mix up cause and effect and we know how governments like playing with statistics. I don't see if I were to drive along a totally empty motorway and suddenly decreased my speed by 1mph I'd be instantly 5% safer.