[Closed] Diesel fuel economy on shortish heavy traffic trips?

The anecdotal evidence is that my fiance's 1.4 TDI Polo is much more economical that her 1.2 16V clio on a 14mile stop-start commute.

15 miles is quite a long time in heavy traffic, so the warmup factor is less of an issue.

I wouldn't say that diesels are particularly bad in heavy traffic as long as they are warm.

ONLY heavy slow traffic and no higher speed driving is a bad idea though, due to coking issues.

Incidentally, this morning's commute was 11 miles, involving a couple of traffic lights, some 70/50mph dual carriageway and the M3. It took about 8 miles and 12 minutes before the coolant got to the normal 90 degrees ie most of the journey.