A rather clever way of capturing energy as vehicles slow down is to store the energy you'd use in braking as gravitational energy. This way of storing energy is used on a number of central London underground stations by constructing the stations at the top of a small hill in the track. Once built, the hump-back-station design has the handy effect of naturally slowing trains down as they approach a station and naturally accelerating them as they leave a station. Apparently, on London's Victoria line this saves 5% in energy and helps the trains run 9% faster.

You're not always going to be able to put a slope just where you need to slow down, unfortunately. However, it makes a ton of sense for pedestrian crossings where raising the crossing to the level of the payment means pedestrians don't have kerbs to negotiate and cars are naturally encouraged to slow down.

Victoria line data from Sustainable Energy without the Hot Air, by the late David JC MacKay

Hump-back stations

An average car, sat idling, can produce exhaust emissions to fill 150 balloons. That's a lot of balloons to imagine puffing away out of the cars idling outside a school for a pickup, say. Other tests have found (pdf) that for any time over 10s fuel use and emissions are always greater when idling than turning off the engine and restarting. Spread the word.

Of course, if you have an electric car this won't apply.

I did draw 150 balloons, but a few of them didn't fit on the page.

Idling

I think it would be interesting if we could see the real shape of your favourite crossing marked on the road. It’d probably help more people cross and traffic get stopped less. And, hopefully, no casualties.

Our senses are built to take in information at human pace

The real shape of a crossing

It took me many years to figure out that if you stand diagonally you brace yourself better for both front-back jolts and side-to-side jostles.

Stand diagonally on transport

A micromort is a one in one million chance of sudden death during the activity. You get a day of regular living for one micromort (though clearly that probably depends on what your average day is). Turns out you get a lot further per micromort by car, and that motorways are by far the safest form of road. You’ll experience 7 micromorts from running a marathon and 39,427 from climbing Everest.

Introduced by Stanford Professor, Ronald Howard.

Micromort: The unit of death

Best travel choices in London

Sure the big city is worse than the country. But the reality is back streets in a big city are significantly better than the busy streets in a big city, and air pollution changes massively even for small children down at the height of exhausts versus adults standing higher.

So if you’re not about to move to the country you could help yourself a lot nonetheless by taking the back streets (I read this premise in Focus magazine, but can’t find an online link to reference).

Pollution is highly localized: take the back streets

I believe I first heard this on a Radiolab episode, but I can’t remember for sure. Since hearing it, I’ve reflected on it many times and can’t help but think there’s some truth in it.

For me it’s kind of why we’re just not that good at processing the scenery whizzing by from a car or train, and why cycling and walking are just about the best ways of getting around.

Alain de Botton, in The Art of Travel, has some great observations about why trains are so great for thinking, which I think has a lot to do with this - we have time to think, with a helpful intermission of the semi-connected landscape and houses passing by that we can only process for so long before we turn back to our thoughts. I love trains.

Because there’s only one way out and it’s a long walk and wait for the lift otherwise.

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Category: transport