Always amazed me why our speed limits are so high in general. USA/Canada have lower limits, and they don't have the same congestion or high fuel prices, many European countries are lower too. Our limits were set when not so many vehicles on road and cars weren't so fast so 70 seemed almost impossible to drive at. We need to lower the limits, folk need to stop speeding, it is against the law, penalties need to be more severe. Constantly driving about and some idiots is speeding ahead thinking he/she will get somewhere quicker only to find I arrive same place about 2 seconds later. Speed does not mean efficient or safe driving it means IDIOT.
And this shows such incredible ignorance about driving it is scary...
do you really think that USA congestion is to do with speed limits?
USA = 9.834 million km2 / 318.9 million people (ish)
UK = 242,495 km2 / 64.1 million people (ish)
So the USA is 40 * the UK in size and c. 5 times the people - so 8 times as empty on average!
and how on earth does anyone think there is a correlation between fuel prices and speed limits - really?!
70mph was set at a time when manufacturers were using the newly opened M1 to test their cars at high speed in december 1965
and have you actually read what you have written?!
:
Speed does not mean efficient or safe driving it means IDIOT.
I hate to break the news to you, but if a car is moving you have speed 
come back when you have some logic and empirical evidence - this attitude is what is so so wrong with our society - based on fear, mistrust and inaccurate information...
in 2011 the IAM analysed the data released by the government spanning 700,000 accidents across the 2005-2009 period
it raised some very interesting points...
only 13.9% of fatal accidents involved speed above the speed limit
15.9% involved the driver not being able to handle a hazard (e.g. bend) even though under the speed limit
biggest issue at 65%+ of accidents - driver error inc:
- not looking properly (20.5%
- loss of control (34%)
- poor turn / manoeuvre (12%)
- failing to judge another road user's path / speed (11.6%)
second biggest issue - injudicious accident - i.e. not an error of handling - but an error of judgement
- getting hazards wrong / speed into hazards (15.9%)
- exceeded speed limit (13.9%)
- down to failing to observe a give-way or stop sign (2.1%)
third issue - behaviour or experience (28%) inc:
- careless / reckless / in a hurry (17%)
- aggressive driving (8.3%)
- learner / inexperienced (5.3%)
fourth issue - impairment or distraction (19.6%) inc:
- alcohol (9.6%)
- distraction in vehicle (2.6%)
even more interesting - 18%+ involve pedestrians only of which 10% was the pedestrian failing to look properly
so, yes, speed is a factor in a % of fatalities (but breaking the speed limit is only 13.9%) and the over-riding message is that it is driver error not just speed - bearing in mind that 86.1% of fatalities involve the car being below the speed limit...
the focus needs to be on driver training and improvement - not just worrying about a figure on a speedo out of context