What’s Your Effective Speed

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What's Your Effective Speed
What's Your Effective Speed

Dirk von Schneidemesser wrote a thought-provoking article earlier this month in Urbanist Magazine in which he discussed the difference between average speed and effective speed.

We are used to working out distance covered in a given time period, (distance divided by time taken) which results in a value in miles or km per hour. The Berlin Senate has provided an estimate of 24.9 km/hour as the average speed in Berlin for motorists, which seems substantially higher than the estimate of 12.3 km/hour as the average speed of cyclists.

Von Schneidemesser then poses an interesting question: what happens if we add in other factors related to our mobility, such as time taken to clear the windscreen of ice in the winter, pump up tyres on a bike, and in particular the time spent at work to afford the monthly finance instalment on our vehicle, whether it has 2 or 4 wheels.

This builds on the original thought of Henry David Thoreau in his 1854 book “Walden” in which he claimed he would be able to walk faster around the world than a friend who set out to do the same journey, if you take into account the time the friend would need to take to earn the wages to pay for his train tickets. The concept of “effective speed” was born and von Schneidemesser has revisited it.

He explains that he cycles at about 17km/hr and earns about €15 per hour and spends some €300 a year on his bike. The German car club ADAC has provided estimates of annual running costs of different cars and von Schneidemesser took two examples: the Renault Twingo and the Mercedes S500 at €4392 and €24,792 respectively. He freely admits that if you earn more than him, your effective speed becomes faster. If he owned one of these car models and drove the same distance that he cycles, his effective speed in a Twingo would be 8.1 km/hr or just 2km/hr in the Mercedes S500.

Some very detailed calculations of effective speed have been carried out by Paul Tranter, an Associate Professor at the University of New South Wales in Canberra, Australia, who has calculated that the money saved by owning a bicycle instead of a car would allow city dwellers to retire 10 to 15 years earlier. Tranter develops his thesis in great depth, comparing also effective speed to social speed, which he defines as effective speed plus external costs which includes the cost for streets to be built and maintained, noise control and damage, and the cost of greenhouse gas emissions.

Tranter calculates that a cyclist’s effective speed in Canberra would need to be 21.5 km/hr to be faster than a motorist, but this is the extreme end of the bell curve. In Melbourne, Tokyo or Los Angeles, the same cyclist would only have to average an effective speed of some 14 km/hr, which falls to 12 km/hr in Hamburg, and as low as 8 km/hr in London or Delhi.

Von Schneidemesser urges us to have a think before we leave work to climb in to our car, on to ourbike, or lace up our walking shoes, about how fast we’re really going. Is the last hour of work worth it, in order to ride home in a car? Or could you leave earlier – like 10 to 15 years earlier!

There are other great articles by von Schneidemesser at Urbanist Magazine.

 

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