One key is to make sure the tail-lights paint a nice graphic line through the frame such as an s-curve. This can be a little tough on a flat prairie!
Although there was a fair amount of light pollution, some of the stars popped through nicely. With a wide lens like my 16mm lens, you can usually leave the shutter open for about 30 seconds before the stars start to blur. The general rule is to divide your focal length (in full frame camera terms) into 500. Here, 500/16 = 31 seconds of expsoure to keep sharp stars.
Night-time streak of car taillights on Blackland Prairie at Clymer Meadow Preserve, Texas Nature Conservancy, Greenville, Texas, USA.
Canon 1Ds Mark III. 16mm lens. ISO 800. f/5.6 @ 30 seconds
Night Photography Resources
Lightstalking provides an excellent resource titled How to Master Night Sky Photography with lots of helpful tips and links.
Night Photography Workshops
Several of my photo workshops feature night photography. Contact me if you are interested and I can provide more information.
Night Photography Posts
Check out some of my other blog posts about photographing at night.