Higher speeds produce disproportionately more CO2 emissions. Large reductions can be made by relatively small adjustments to our driving behaviour. This can be done very easily and quickly with a quantifiable result which would be just one of the many steps humanity must take to halt climate change and progress towards carbon subzero. Doing this would also negate the perceived need for replacing single carriageway A roads by huge “expressway”dual roads. We could then cancel the whole £27+ billion RS2014 road building plan cancelling still further emissions of the construction and embedded carbon in the construction materials. As many of those materials derive from fossil fuels, mainly crude oil, cancelling their production instantly reduces the need for numbers of oil and gas well extractions or exploration. From their cancellation investment would naturally shift to renewable energy innovations and into environment repair carbon sequestration projects and ecosystem renewal. Repair of environmental damage would increase biodiversity which in turn would benefit the health and well being of the whole of humanity. Then spreading to other countries the chain reaction of one small behavioural change will have a massive positive effect on the most important issue of our day - Global Climate Change.