More info here http://www.edeva.se/en/#actibump
The purpose of a traffic-calming installation is
to cause road traffic to reduce speed and in
this way reduce the risks for other road users.
The speed of a vehicle approaching the
Actibump is recorded with the aid of radar
measurement. No action is taken if the vehicle
speed is within the legal limit, but if it is
approaching faster than is permitted, a part
of the roadway pivots downwards, creating
an edge.