Photography - Light Trails

On a nice warm night in February we joined some photographers to do a night shoot (light trails). The intention is to get some nice light trails from cars lights by using long exposure times. Required equipment for this (besides the obvious camera) is a tripod and a polariser filter for your lens(ideally neutral density filter, but polariser works as a low level neutral density filter as well). Also good to have with you is a remote (or cable) shutter to absolutely minimise the chances of vibration during the exposure of the shots.

Finally a good location (an overpass over the freeway) and some patience :-).

Here is what the view looks like with a not to long exposure (2 seconds) while it was still pretty light (maybe 20 minutes before sunset). What do you think of the train? :-) and a shot taken 20 minutes later this time with an exposure time of 20 seconds (and the sun already getting near the horizon):





Of course the darker it becomes the longer the exposure time needs to be OR the aperture needs to be adjusted (wider). Obviousle I have taken a fair few shots that night. I think these four were the best (with some post processing of course :-)). These 4 shots were taken between 7:24 and 7:53 PM. The exposure times vary (from 1st till 4th) from 13 to 25 seconds and some variations in aperture.

I'd love to hear which one you'd find the best (and why)...: