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Everyone enjoys roads, they provide valuable play areas
for the world's children and put 10m of Asphalt between
the idiots at No. 24 and me. However, when people are
driving about on roads, they sometimes feel the need to
be on a different, often perpendicular, road. This has
forced the ugly
compromise that is the intersection, with
cars stopping and starting all over the place in a
orgy of wasted kinetic energy.
Now, should the road slowly rise on approach to the
intersection... cars would be forced to trade kinetic
for potential energy. The structure in question would be
on the entry-to-the-intersection side of the road and
similar to a long gentle speed bump, maximum height
about 10cm. So, if the cars were slowing to a stop, then
portion of the kinetic energy would be converted to
potential energy. Assuming the car is to resume
movement, this potential energy will be regained as the
car descends the small downhill section. If the car
through the intersection without stopping, then the
energy will be lost and regained pretty seamlessly.
Some considerations: the rise and fall cannot be too
sudden... otherwise the benefit will be lost, heating the
Side benefit: when stationary at the intersection, you
be 10cm higher than normal. This is a useful aid to
Numbers: The kinetic energy of a 2000kg car at about
5mph is about 5kJ.
Raising that same car 10cm uses about 2/5ths of that.
Meaning that about 2kJ is saved per car per
There's about 1.3x10*8 J in a gallon of petrol. which is
probably used at about 25% efficiency. Which means 1
gallon is saved for every 16250 car-junctions. Of course
won't work for more than say... the first 2-3 cars in a
queue. So don't get all carried away with thoughts of
elevated stop lights
WhiteWiz, Mar 26 2004 plus an illustration by [bris]. Doesn't get more halfbaked than that! [pocmloc, Nov 23 2012]
my own horn, etc.
for highways. [FlyingToaster, Nov 23 2012]
William Heath Robinson
Inspired. Definite Halfbakery material. [8th of 7, Nov 23 2012]
||I'll bun it, but good luck getting the motoring public to
understand how it works. They already have enough
trouble with things like turn indicators, stop signs, and the
definition of 'yield'.
||There are some raised intersections where I live and they have about one wreck a day because one person is turning left on green without being able to see down the hill, meanwhile the car coming the other way decides to add kinetic energy with their V8 instead of trading it for potential and slams into the other car at 50mph.
||Your text is nicer but you can't argue with prior art. <link>
||OK, so I should clarify: the whole intersection is not
raised. Only one lane on the approach... so the Left
in UK/India/Japan/Australia or the Right in
Djibouti/Gabon/Vanuatu. Also, there is no angle.
The raised section has a flat top, the gradient will be
a couple of car lengths back. There's a couple of
reasons for this: 1. doing a hill start is a pain. 2. the
angle will ruin visibility and also, headlights will be
pointing all over the place.
||William Heath Robinson might have been a worthy competitor ...