Make the speed-control ramps (oldies -- read 'sleeping policeman') out of a very thick BUT HOLLOW semi-rigid rubber. There is a hole in the rubber to the hollow bit (filled with air) - so the speed ramp normally holds its shape though its bendible rigidity (if that makes sense - Imagine if you crush a plastic bottle slightly and then let go .. it reinflates back to its original shape).

The hole is precisely machined so that if a car passes over it at 30mph or less -- the air can fly out of the whole ramp-- so the speed ramp under the weight of the car simple collapses to flat and the law-abiding citizen doesn't suffer a bumpy ride. Naturally it re-inflates itself once the car is past like your slightly squashed plastic bottle reinflates itself when you let go.

A car goes speeding past at an illegal 50mph -- the air doesn't escape quick enough -- the car suffers the speedramp in full effect.

Law abiding citizens no longer have to suffer the grief of lumpy speedramps - speeders still slow down for them! This could work for different speed zones, with different sized 'air holes'.
-- britboy, Mar 16 2007

Custard Filled Speed Bumps Custard-Filled_20Speed_20Bumps
in the same category and an HB classic. Covering roughly the same territory. [calum, Mar 16 2007]

put them to work, I say. road-hump_20wine_20press
[po, Mar 17 2007]

Just so long as it deflates sensibly, and doesn't wiggle or anything. Or you'll have a queue of cyclists and motorcyclists at your door to beat you up.

You'd also need to solve the problem of different wheel-loading on different vehicles. A Smart Car might not deflate it properly, but a bus might burst it?
-- Defiler, Mar 16 2007


Nice concept.
-- david_scothern, Mar 16 2007


Good idea, though air is no substitute for custard.

One request. Does anyone know the name for those whistles which have a spinning thing in them, so that when you blow them they rise in pitch a bit like a tiny buzzy engine revving? Whatever they are called, I want them fitted on this thing's blowhole.
-- MaxwellBuchanan, Mar 16 2007



random, halfbakery