A Christmas present given to me in my youth was a set of encyclopaedias. I read about Piltdown man the missing link and an article on the formation of the canals on Mars which included a map naming the canals. Of course those perceived gems of wisdom were later found to be fraudulent but they illustrate that myths perpetuate and too few of us are willing to question the great and the good. I stumbled upon a modern example yesterday when I typed in “Traffic calming and environmental effects” into my favourite internet search engine. The first three pages of search results were mainly postings from authorities claiming how their measures cut pollution. Let us dwell on this a moment.
All piston engines generate a high pressure in their cylinders when producing power. When the engine is being used to destroy energy, say, when a car is slowing for a traffic calming measure then a partial vacuum is produced within itself. Since vehicles use oil for lubrication and nature abhors a vacuum, the oil obliges nature by squeezing its way past piston rings, valve and bearing seals and gets into the cylinder and exhaust pipe. There it lurks until the driver accelerates once more. Lubricating oil is not primarily designed to burn cleanly and eventually disappears in a puff of blue smoke. Usually this is diluted by exhaust gases and we never notice it. Some oil gets trapped in the exhaust system where it puffs out the next time the engine roars in anger. We cannot stop it – it will get out somehow. You need not be a rocket scientist to realise that slowing vehicles are not good for air quality.
Worse still is the carbon dioxide generated as vehicles accelerate out of the traffic calming devices. You can measure this if you have a car fitted with a digital fuel consumption meter. The read-out is usually on a dashboard display and normally shows the time. ‘Anorak’ types know how to set this to display average speed and fuel consumption. I used my device to illustrate the argument that needless slowing will cause pollution.
When driving at a steady 60 mph in 6th gear along an empty road I recorded 60 mpg. I then simulated a series of road humps by repeatedly slowing to 10 mph and accelerating again. Average speed dropped to 15mph and consumption was a low 20 mpg. I had taken four times longer going along that road and used three times more fuel. Since the carbon atoms in the fuel were not created or destroyed when the fuel was consumed, my carbon emissions at the lower speed had increased THREE HUNDRED PERCENT!
Believe me, animals which travel great distances on little resources do not dawdle. Swifts, for example, do an annual return journey halfway round the World and produce only a few grams of carbon dioxide. They would run out of fuel if they had to keep stopping. They travel quite fast – in fact, if you could excuse the pun, they travel quite swiftly. If cars could be given roads which allowed swift travel then carbon emissions would drop.
This little experiment proves that traffic calming measures ADD to pollution. Authorities claiming otherwise are living on another planet – Mars, perhaps?
More information can be found at , the anti speed hump page.