Those interested in buying a used car have been urged to consider how quickly their chosen vehicle's value may depreciate. According to the HPI, the credit crunch is likely to take its toll on new car registrations as people look instead to the used car markets. However, Martin Keighley, used car valuations expert at the HPI, said buyers, who may include car loans customers, needed to "think carefully about their next purchase". "It is really important that consumers think about a car's potential to depreciate before parting with their cash," Mr Keighley advised. Vehicles that are "small and economical" and produce low carbon dioxide emissions are likely to be the best value for money, he added. The expert predicted that large petrol engines will become increasingly undesirable as motorists choose cheaper alternatives. HPI claims to have been providing vehicle checks for used cars since 1938. ...