[DamonD]

Is it possible to change it so that police bars glow and shit during the day?

[DanishHaq]

It only doesn't do that with one specific weather, or one specific time I think, try and use a different weather and time combination and replace it with the one that you've got. I've been on servers with sirens blaring and lights flashing in broad daylight.

[DamonD]

But is this a scriptable action? Can I just script something, to make it work

[DanishHaq]

Not yet, it's the same on single player too as far as I know. Unless you use the siren object if the weather and time is X and X.

[Ayumi]

Have it so your gamemode automatically sets it to weather 2.

However it is possible to script it in so that they have to press a button/turn them on via a command in order to make the glow appear.

Check the filterscrips section, there is a few like stated above available there.