This week a consultation was announced to the increase the speed limit on motorways to 80 mph.
Phillip Hammond, Transport Secretary 
Brake, the road safety charity, called the proposal “shameful” 
Professor Stephen Glaister, director of the RAC Foundation, said:
“There are good reasons for making 80 the new 70, and good reasons not to. Drivers travelling that 10mph quicker might reach their destination sooner but will use about 20% more fuel and emit 20% more CO2. There is also likely to be a slight increase in road casualties. And what about enforcement? If police follow existing guidelines, many people could do 90mph before action is taken.” 
Energy prices have increased in recent times, and that has been when the world economy has been struggling. If growth begins again, that will increase the price of oil and gas. We also know that oil supplies are dwindling, and this allied with the rapid modernisation of many of the world’s poorer countries will only push the demand and price upwards.
A modern car achieves a maximum efficiency at around 55 – 60 mph. Driving at 70 mph reduces fuel efficiency by 17%. At 80 mph this reduces by 28%. Given that driving at 80 mph would certainly involve a lot of rapid acceleration, sharp braking and more acceleration to avoid accidents, this loss of efficiency is probably conservative.
At a time when we need to reduce the emission of CO2 gases and the demand for oil, an 80 mph would be a retrograde step.
ACPO recommend that speed limits are enforced with an allowance of 10% + 2 mph. That would mean that in effect a 80 mph speed limit would be in effect be a 90 mph speed limit.
At 80 mph, a car travels 35 metres every second. At 90 mph this goes up to 40 metres. Any motorway veteran will tell you that cars often travel in the fast lane only a few car lengths apart. The consequences of travelling at 80 or 90 mph will be more devastating accidents with multiple fatalities and serous delays as whole stretches of motorway are closed while emergency services deal with the carnage.
Cars have got stronger and safer, brakes are better than ever before and can easily beat our speed limits.
However, there is no evidence that drivers have got better. They sit in their cars surrounded by an increasing array of gadgets and gizmos, all distracting the driver. Drivers still over-estimate their own driving ability.
The only conclusion I can come to regarding this proposed increase is that it will be polluting, cost more lives and should be resisted.