Vehicle detector, comprising: a vehicle sensor arranged for sensing disturbances caused by a vehicle; a digitizer connected to said vehicle sensor and arranged for encoding a signal from said vehicle sensor into a digital representation; a memory (18, 24) connected to said digitizer and arranged for storing said digital representation; an antenna; a transmitter connected to said memory (18, 24) and said antenna for transmitting signals, comprising requests for operation instructions, to a traffic surveillance node by use of radio signals; a receiver connected to said antenna for receiving signals, comprising operation instructions, from said traffic, surveillance node; a controller arranged for controlling operation of said vehicle sensor, said digitizer, said memory (18, 24), said receiver and said transmitter; a battery powering said vehicle sensor, said transmitter and said receiver; and a housing enclosing said vehicle sensor, said digitizer, said memory (18, 24), said transmitter, said receiver and said controller; said housing providing protection against mechanical damage and moisture for said vehicle sensor, said digitizer, said memory (18, 24), said transmitter, said receiver and said controller, thereby enabling said housing to be placed under ground; said antenna is provided outside said housing and at a distance from said housing for enabling placement of said antenna within a roadway surface coating; and said controller is arranged for turning off said transmitter, said receiver, and said vehicle sensor during a predetermined inactivity period and for activating said transmitter and said receiver and transmitting a request for further operation instructions when said inactivity period is ended. a vehicle sensor arranged for sensing disturbances caused by a vehicle; a digitizer connected to said vehicle sensor and arranged for encoding a signal from said vehicle sensor into a digital representation; a memory (18, 24) connected to said digitizer and arranged for storing said digital representation; an antenna; a transmitter connected to said memory (18, 24) and said antenna for transmitting signals, comprising requests for operation instructions, to a traffic surveillance node by use of radio signals; a receiver connected to said antenna for receiving signals, comprising operation instructions, from said traffic, surveillance node; a controller arranged for controlling operation of said vehicle sensor, said digitizer, said memory (18, 24), said receiver and said transmitter; a battery powering said vehicle sensor, said transmitter and said receiver; and a housing enclosing said vehicle sensor, said digitizer, said memory (18, 24), said transmitter, said receiver and said controller; said housing providing protection against mechanical damage and moisture for said vehicle sensor, said digitizer, said memory (18, 24), said transmitter, said receiver and said controller, thereby enabling said housing to be placed under ground; said antenna is provided outside said housing and at a distance from said housing for enabling placement of said antenna within a roadway surface coating; and said controller is arranged for turning off said transmitter, said receiver, and said vehicle sensor during a predetermined inactivity period and for activating said transmitter and said receiver and transmitting a request for further operation instructions when said inactivity period is ended.