You can use long exposure for a variety of effects. A couple of posts ago I showed an image of Brighton’s West Pier. In that example, long exposure was used to flatten to water and to give the sky a dreamy feeling.
In today’s image the long exposure was used to give a feeling of speed and danger. The image was taken from the passenger seat of the car using a 30 second exposure. The movement of the car's brake lights was captured along with the headlights which have passed by on the other side.
The overall feeling of danger was helped by the low ambient lighting.
I hope you like the picture, which reminds me of the back of the original batmobile (see what you think compared to this image by Paul Ward at fineartamerica.com)?
Photographing London, Surrey and beyond. From the top of the Shard to the end of the garden. . .