Question

radar devices are used by law enforcement to be sure that individuals are driving safely. they tell the officer how fast the vehicle is traveling at that specific moment in time. the radar device determines the vehicle's instantaneous speed. acceleration. maximum velocity. average speed.

Answer 1

The radar device determines the vehicle's instantaneous speed.

I would argue that the purpose of the device is not to determine
whether individuals are driving safely.  They only determine whether
individuals are driving within legal speed limits.  There's much more
to 'safe' driving than that, but the radar gun can't detect it.