Lens Flair

As my most common subject is the scene of various emergencies, I encounter many lighting difficulties from low light to no light. Increasingly common are bright LED emergency lights on vehicles replacing the older strobe lights. These often fill the frame with a red ghost layer, or unsightly lens flares.

Any tips to help prevent these flares?

I mostly have the issue with my Nikon f/4 16-35.

Try and avoid shooting along the same plain where the light will be focused directly. Shoot at angles facing away from the leds.

Your lens hood might help, but not for lights that are in the scene. If you have a filter on your lens for protection, try taking it off. The extra glass can make things worse.

Yup it is probably the Filter, it happens with the sun too, I often have to take the UV filter off when I am shooting into the sun

I don't use filters

Veiling flare is almost inevitable when light from a strong enough source hits the front lens-element directly. If a lens hood doesn't stop it, and you can't change your location to prevent it, then you'll either have to live with the flaring or learn to correct for it in post' as best you can.

Using a Levels Adjustment Layer and/a Contrast Adjustment Layer can help but it's not always a 100% solution.