The officer was conducting speed tests on Nicklin Way on the Sunshine Coast about 3pm today when a car that was approaching him did not stop.
The car swerved around the officer and the officer threw his speed radar gun at the window of the passing car.
The P-plater continued to drive along the road.
The incident occurred in a school zone where the speed limit was 40km/h.
Queensland Police said the officer was acting in self-defence and alleged the driver has a number of traffic infringements against his name.
Police have launched an investigation into the incident.