In my 8 yrs of flying Police here in the UK (previously lived QLD) I believe a helicopter makes all the difference in making a pursuit safer, criminals are well aware that they have limited time till the helicopter arrives overhead and many a pursuit has ceased as soon as soon as the helicopter is overhead, but the greatest help it offers is allowing the pursuing police vehicles to back of and take the pressure of the criminal while still keeping the vehicle and criminal in view. Video camera's, Thermal Imaging and video downlink all ensure the criminal has little chance of escape.