Anyone ever do these in your renderings? What's the best and easiest way? I'm looking to do some night shots renderings to experiment with.

and another....thanks to anyone who can help me out! :not worth

Those look like night shots with the actual render inserted.

Create a long red/white line on a new layer of appropriate scale to that of the closest location of the taillight. Use the filter gausian blur and play with the settings until it is what you desire. Then you can also use edit/transform perspective or skew to adjust the thickness and perspective to match your rendering, or rotate as required. You can see the attached image of the example. Took about 10 minutes to do so I could post it. I would be interested in hearing if there is a way to do it in sketchup. That would be sweet.

Anyone ever do these in your renderings? What's the best and easiest way? I'm looking to do some night shots renderings to experiment with.
the easiest way is photoshop, as drichards suggested.

draw lines in white with 10px of width, motion blur it, gaussian blur it, copy it, apply layer effect on the copy (colour overlay in red, outer glow in red, etc.).
Then you can begin stretching it: with transform first (Ctrl-T) and with liquify if you need to... then copy the layer and transform it agin to keep perspective correct...
You can add layers of other colours to give more depth (yellows, greens, etc.)

Thanks for the instuctions! I'll give it a shot and see what I come out with. Thanks again. :)