Light trails and Zoom Technique

Images of light trails can be made quite easily by photographing the headlights and tail lights of any moving vehicles including cars, trucks, motorbikes, etc.

This subject does not include 'star trails' or those with lighted sparklers or 'fireworks' but can include a zoomed image of heavy vehicles at a busy intersection. I will explain more about that later.
To photograph vehicle light trails, it is best done with a camera that is capable of being set manually on the "B" (bulb) or "T" setting and after sunset obviously, but particularly before the sky becomes black, so that there is still enough light in the sky to allow surroundings to be seen in the image. This is important, as it eliminates blacked out areas and negative space around the image.
The light trails themselves should be of reasonable length, of a minimum of 5 seconds, but exposures of up to 10 seconds may be needed, depending on the distance you are from the light source, or how long it takes for the vehicle/s to travel from one point to the other.
Bridges, buildings, hilltops, or any high vantage point should be suitable for getting a fair result.
Suggested sites might include traffic lit intersections, from bridges over motorways, speedway meetings, or night motor cross events, or any place where there is a lot of activity with moving vehicle lights.

For best results, your equipment should include:
A sturdy tripod, or some device for stabilizing your camera through lengthy exposures.
A camera that is capable of taking exposures of 5-10 seconds or more, with a zoom lens in the range 18-200mm to cover most situations.
A remote shutter release would be an asset, but not essential.
DSLR users could set their ISO ratings at 200 or 400, as an example.
A small torch and extra batteries would also be handy.

The zooming technique:
This is best done with the camera fully stabilized at a location where there are a lot of lights of various colours. Like for instance, a major traffic lit intersection that has a heavy flow of traffic. A high vantage point would help.
In contrast to photographing light trails, this is best done when the sky and outer surrounds are black.This will accentuate the light's colours as they are zoomed out across the image.
Using the 'B' (bulb) or "T'' setting with a small aperture (large number). 

Aim the camera at the centre of attraction with the lens at its shortest focal length (closed) and work on an exposure of about 5 seconds and as soon as you release the shutter, taking great care not to move the camera too much, zoom the lens out for that 5 second period, then immediately close the shutter. 
There is no need to use a stopwatch for this, it is not critical, but that time is merely set to give you an idea. After a bit of practice you will soon get the hang of it and develop your own way of doing it and you can produce some pretty unique results too. "Good Luck!"