flashing lights (actually, they dont flas, only dim) is easier on the bulbs and the generators -> less fuel use and longer lamp life.
most of that type of lights are Xenon tubes, which need a lot of voltage (15000V) to operate, when you cut the current, the gas keeps glowing for a while, and they switch it on after a set time... is easier on th power converter
As someone that lives in the land of televised high speed chases I can tell you the tv choppers were propably a good ways off. The lenses they have on the camers are incredible these days.