I like the image, but the lights are dark. It is necessary to lighten it. We have previously saved a mask for the headlights, which we will use. After the Merge node (overlay) we are going to add a ColorCorrect node (hotkey C or Color> ColorCorrect). If we select Merge, and we add a ColorCorrect node, it immediately connects in after it; if not, then just drag the arrow from Merge to the Viewer or from the Viewer to Merge. Set the following setting for the ColorCorrect node (Fig.30).

Fig.30
This had made the whole scene change in gamma, but we only need lights. Connect our headlight mask with the ColorCorrect node. Drag the triangle on the right to our mask pass; it is considered for mask channels. The effect is 0. We must set the ColorCorrect node from where it will take the mask. In the settings window of the ColorCorrect node, go to the Ranges tab and in the mask line choose rgba.red. This will mean that the mask will be taken from the red channel (Fig.31).

Fig.31
I want to add a bit of a glow effect to the lights. Everything is done as with the ColorCorrect node and the settings can be seen in Fig.32.

Fig.32
All that remains is to add a DOF effect, aberration, noise, vignetting, and do some final color correcting. We could do this in Photoshop via plugins, but we're going to do it in Nuke instead. For the DOF effect, we have a ZDepth pass. We need to add the ZDepth pass as an additional channel. Do this with a ShuffleCopy node. Connect input 2 with Glow, and input 1 with our ZDepth pass. In the parameters dialog box of the ShuffleCopy node, from the list, choose "new" (Fig.33).

Fig.33