I currently drive a BMW 3 Series ('99), but due to a new job am considering buying a diesel (2004 1.7CDTI Vauxhall Astra) - mainly due to the difference in cost betwen petrol and diesel. I currently do approximately 30-35 miles per gallon combined and would hope to double that with a diesel? I have about a 20 mile round trip commute, but often have to go out during the day a number of times. Some daytime journeys can be as short as 2-3 miles but normally in the 10-20 mile region - will these daytime journey's be long enough not to clog the diesel particulate filter?