Mind the hump

Speed fiends in Israel are in for a rough ride. Defence researchers have
“improved” a traffic-calming road hump. Conventional humps are made of concrete
or asphalt, and make a car bounce even if it’s travelling within the speed
limit. The new hump is made of rubber, with a sealed air chamber connected to
the atmosphere by two valved vents (GB 2 336 867). Both valves let air in, but
only one lets it out. The weight of a car forces air out of the one-way valve.
If the car is driving slowly, the hump has time to collapse into…